What is zinc as a therapeutic supplement?

Overview

Zinc is an important element that is found in every cell in the body. More than three hundred enzymes in the body need zinc in order to function properly. Although the amount of zinc needed in the daily diet is tiny, it is very important that individuals get it. However, the evidence suggests that many people do not get enough. Mild zinc deficiency seems to be fairly common, and for this reason, taking a zinc supplement at nutritional doses may be a good idea.

However, taking too much zinc is not a good idea—it can cause toxicity. This article discusses the possible uses of zinc at various doses.

Requirements and Sources

The official U.S. recommendations (in milligrams, or mg) for daily intake of zinc are as follows:

Infants aged 0 to 6 months (2 mg) and 7 to 12 months (3 mg); children aged 1 to 3 years (3 mg) and 4 to 8 years (5 mg); boys aged 9 to 13 years (8 mg); males aged 14 years and older (11 mg); females aged 9 to 13 years (8 mg) and 14 to 18 years (9 mg); women (8 mg); pregnant girls (13 mg) and pregnant women (11 mg); and nursing girls (14 mg) and nursing women (12 mg).

The average diet in the developed world may provide insufficient zinc, especially in women, adolescents, infants, and the elderly. Thus, it might be a good idea to increase one’s intake of zinc.

Various drugs may tend to reduce zinc levels in the body by inhibiting its
absorption or increasing its excretion. These include captopril and possibly other
angiotensin-converting enzyme (ACE) inhibitors, oral
contraceptives, thiazide diuretics, and drugs that reduce stomach acid,
including H2 blockers and proton pump inhibitors. Certain
nutrients may also inhibit zinc absorption, including calcium, soy, manganese,
copper, and iron. Contrary to previous reports, folate is not likely to have this
effect.

Oysters have a very high zinc content; one oyster provides
at least the full daily dose of zinc—about 8 to 15 mg. Besides oysters, other
types of shellfish, along with poultry and meat (especially organ meats), are high
in zinc, providing 1 to 8 mg of zinc per serving. Whole grains, nuts, and seeds
provide smaller amounts of zinc, ranging from 0.2 to about 3 mg per serving, and
the zinc from them is not as absorbable. Breakfast cereals and nutrition bars are
often fortified with substantial amounts of zinc.

Zinc can also be taken as a nutritional supplement in one of many forms. Zinc citrate, zinc acetate, or zinc picolinate may be the best absorbed, although zinc sulfate is less expensive. People who purchase a supplement should be aware of the difference between the milligrams of actual zinc that the product contains (so-called elemental zinc) and the total milligrams of the zinc product, which includes the weight of the sulfate, picolinate, and so forth. All dosages given in this article refer to elemental zinc (unless otherwise stated).

Therapeutic Dosages

For most purposes, zinc should simply be taken at the recommended daily requirements of 8 to 15 mg. Some evidence suggests that 30 mg of zinc daily may be helpful for acne. This is a safe dose for most people. However, in most studies of zinc for acne, a much higher dose was used: 90 mg daily or more. Doses this high should be used only under physician supervision. Potentially dangerous doses of zinc have also been recommended for sickle cell anemia, macular degeneration, and rheumatoid arthritis.

For best absorption, zinc supplements should not be taken at the same time as
high-fiber foods. However, many high-fiber foods provide zinc in
themselves.

Zinc gluconate may be slightly better absorbed than zinc oxide.

When taking zinc for a long time, it is advisable to also take 1 to 3 mg of
copper daily because zinc supplements can cause copper
deficiency. Zinc may also interfere with magnesium and iron absorption.

Zinc is used topically in lozenge or nasal gel form for the treatment of colds. When using zinc this way, the purpose is not to increase zinc levels in the body but to interfere with the action of viruses in the back of the throat or in the nose. It appears that of the common forms of zinc, only zinc gluconate and zinc acetate have the required antiviral properties. Certain sweeteners and flavorings used in lozenges can block zinc’s antiviral action. Dextrose, sucrose, mannitol, and sorbitol appear to be fine, but citric acid and tartaric acid are not. The information on glycine as a flavoring agent is a bit equivocal.

When using zinc nasal gel products, users should not deeply inhale, as this may cause severe pain. Rather, they should simply squeeze the gel into the nose, according to the directions.

Therapeutic Uses

Use of zinc nasal spray or zinc lozenges at the beginning of a cold may reduce the duration and severity of symptoms, but study results are somewhat inconsistent. These treatments are thought to work by directly interfering with viruses in the nose and throat, and they involve relatively high doses of zinc used for a short time.

Zinc can also be taken long term at nutritional doses orally to improve overall immunity and reduce risk of infection. However, this approach probably works only if individuals are deficient in zinc to begin with.

A significant body of evidence suggests that oral zinc can reduce symptoms of acne. However, in most studies, potentially toxic doses were used, and in any case, the benefits appear to be rather slight.

Growing evidence suggests that oral zinc, especially in combination with
antioxidants, can help slow the progression of
macular
degeneration. Oral zinc has also shown promise for sickle
cell anemia, attention deficit disorder (ADD), and stomach ulcers. Zinc has also
been shown to be beneficial for acute diarrhea in children, the most convincing
evidence coming from studies done in developing countries. This suggests that zinc
is most useful for this condition in the presence of a nutritional deficiency.
Topical zinc may be helpful for cold sores.

Zinc has shown some promise for treating dysgeusia (impaired taste sensation). In a study of fifty people with idiopathic dysgeusia (impaired taste sensation of no known cause), use of zinc at a rather high dose of 140 mg daily improved taste ability. Another study enrolled seniors with dysgeusia and gave them either placebo or 30 mg of zinc daily; the results were inconclusive. Dysgeusia can also be caused by radiation therapy in the vicinity of the mouth, but overall, the evidence regarding the use of zinc for this purpose is more negative than positive. Kidney dialysis also impairs taste sensation, but once again zinc supplements failed to prove effective. (The use of any mineral supplement by people undergoing kidney dialysis is potentially dangerous.)

In one study, use of zinc appeared to modestly decrease inflammation of the mucous membranes and skin caused by radiation therapy. Weak, contradictory results have been seen in studies of zinc for anorexia nervosa, depression, rheumatoid arthritis, enhancing sexual function in men on kidney dialysis, tinnitus, and warts.

Some studies have found that persons with human immunodeficiency virus
(HIV) infection tend to be deficient in zinc, with levels
dropping lower in more severe disease. Higher zinc levels have been linked to
better immune function and higher CD4+ cell counts, whereas zinc deficiency has
been linked to increased risk of dying from HIV. One preliminary study among
people taking azidothymidine (AZT) found that thirty days of zinc supplementation
led to decreased rates of opportunistic infection over the following two years.
However, other research has linked higher zinc intake to more rapid development of
acquired immunodeficiency syndrome (AIDS). Another study failed to find that zinc
supplementation reduces diarrhea associated with HIV. People who have HIV should
consult their physicians before supplementing with zinc.

Although the evidence that zinc works is not meaningful, the supplement is sometimes recommended for the following conditions: Alzheimer’s disease and minor memory loss in seniors, benign prostatic hyperplasia, bladder infection, cataracts, diabetes, Down syndrome, infertility in men, inflammatory bowel disease (ulcerative colitis and Crohn’s disease), osteoporosis, periodontal disease, prostatitis, psoriasis, and wound and burn healing. An eight-week, double-blind trial of zinc at 67 mg daily failed to find any benefit for eczema symptoms.

Scientific Evidence

Common cold. Lozenges containing zinc gluconate or zinc acetate
have shown somewhat inconsistent but generally positive results for reducing the
severity and duration of the common cold. For example, in a
double-blind trial, one hundred people who were experiencing the early symptoms of
a cold were given a lozenge that contained either 13.3 mg of zinc from zinc
gluconate or a placebo. Participants took the lozenges several times daily until
their cold symptoms subsided. The results were impressive. Coughing disappeared
within 2.2 days in the treated group versus 4 days in the placebo group. Sore
throat disappeared after 1 day versus 3 days in the placebo group, nasal drainage
in 4 days (versus 7 days), and headache in 2 days (versus 3 days). Positive
results have also been seen in double-blind studies of zinc acetate. While not all
studies have been supportive, on balance results appear to favor the effectiveness
of zinc lozenges for treating symptoms of the common cold.

It has been suggested that the exact formulation of the zinc lozenge plays a significant role in its effectiveness. According to this view, certain flavoring agents, such as citric acid and tartaric acid, might prevent zinc from inhibiting viruses. In addition, chemical forms of zinc other than zinc gluconate or zinc acetate might be ineffective. Zinc sulfate in particular might not work. Along the same lines, sweeteners, such as sorbitol, sucrose, dextrose, and mannitol, are said to be fine, while glycine has been discussed in an equivocal manner.

Use of zinc in the nose is somewhat more controversial. In addition to showing inconsistent results in studies, use of zinc nasal gel can cause pain and possibly loss of sense of smell.

For example, in a double-blind, placebo-controlled trial of a widely available zinc nasal gel product, 213 people with a newly starting cold used one squirt of zinc gluconate gel or placebo gel in each nostril every four hours while awake. The results were significant: Treated participants stayed sick an average of 2.3 days, while those receiving placebo were sick for an average of 9 days, a 75 percent reduction in the duration of symptoms. Somewhat more modest, but still significant, relative benefits were seen with zinc nasal gel in a double-blind, placebo-controlled study of eighty people with colds. However, another study, this one involving seventy-seven people, failed to find benefit even with near constant saturation of the nasal passages with zinc gluconate nasal spray. Furthermore, a study of ninety-one people using the standard commercially available nasal spray failed to find benefit. Another double-blind, placebo-controlled trial, this one enrolling 185 persons, failed to find benefit with zinc nasal spray. However, this study used a much lower amount of zinc (fifty times lower) per squirt of spray than was used in the studies just described.

Apart from their direct effect on viruses during an infection, zinc supplements (not lozenges) may play a role in reducing the risk of coming down with a cold in the first place. In a review of two randomized trials, which included 394 healthy children, researchers found that the groups who took zinc had fewer colds, school absences, and prescriptions for antibiotics.

Chronic zinc deficiency is known to weaken the immune system. Although low levels
of zinc are uncommon in healthy children and adults living in developed countries,
deficiencies may be found among the elderly and are widespread among populations
in developing countries. A one-year, double-blind study of fifty nursing home
residents found that zinc supplements reduced rates of infection compared with
placebo. Additionally, in a two-year study of nursing home residents, participants
given zinc and selenium developed illnesses less frequently than those
given placebo.

Numerous studies in developing countries have also found benefit. For example, a six-month, double-blind, placebo-controlled study of 609 preschool children in India found that zinc supplements reduced the rate of respiratory infections by 45 percent. In addition, more than ten other studies performed in developing countries found that zinc supplements were helpful for preventing respiratory and other infections in children, and that zinc might reduce symptom severity.

Cold sores. Cold sores are infections caused by the
herpes virus. One study suggests that topical zinc may be helpful. In this trial,
forty-six individuals with cold sores were treated with a zinc oxide cream or
placebo every two hours until cold sores were resolved. The results showed that
individuals using the cream experienced a reduction in severity of symptoms and a
shorter time to full recovery.

Zinc is thought to interfere with the ability of the herpes virus to reproduce itself. As with colds, the formulation of zinc must be properly designed to release active zinc ions. This study used a special zinc oxide and glycine formulation. Some participants in this study experienced burning and inflammation caused by the zinc itself, but this seldom caused a serious problem.

Macular degeneration. Macular degeneration is one of the most common causes of vision loss in the elderly. A double-blind, placebo-controlled trial evaluated the effects of zinc with or without antioxidants on the progression of macular degeneration in 3,640 individuals in the early stage of the disease. Participants were randomly assigned to receive one of the following: antioxidants (vitamin C 500 mg, vitamin E 400 international units, and beta-carotene 15 mg), or zinc (80 mg) and copper (2 mg), antioxidants plus zinc, or placebo. Copper was administered along with zinc to prevent zinc-induced copper deficiency. The results suggest that zinc alone, or, even better, with antioxidants, significantly slowed the progression of the disease. Previous studies of zinc for macular degeneration found mixed results, but they were much smaller.

There is also some evidence that individuals who make sure to get their dietary requirements of zinc on a daily basis over many years might reduce their risk of developing macular degeneration later in life. Keep in mind that the dosages of zinc used in most of these studies are rather high and should be used only under a physician’s supervision.

Attention deficit disorder. Zinc has shown some promise for
treatment of attention deficit disorder (ADD). In a large (approximately
four-hundred-participant), double-blind, placebo-controlled study, use of zinc at
a dose of 40 mg daily produced statistically significant benefits compared with
placebo among children not using any other treatment. This dose of zinc, while
higher than nutritional needs, should be safe. However, the benefits seen were
quite modest: About 28 percent of the participants given zinc showed improvement
compared with 20 percent in the placebo group.

Another, much smaller double-blind, placebo-controlled study evaluated whether zinc at 15 mg per day could enhance the effect of Ritalin. Again, modest benefits were seen. Finally, extremely weak evidence hints that zinc might enhance the effectiveness of evening primrose oil for ADD.

Acne. Studies suggest that people with acne have lower-than-normal levels of zinc in their bodies. This fact alone does not prove that taking zinc supplements will help acne, but several small double-blind studies involving a total of more than three hundred people have found generally positive results.

In one of these studies, fifty-four people were given either placebo or 135 mg of zinc (as zinc sulfate) daily. Zinc produced slight, but measurable, benefits. Similar results have been seen in other studies using 90 to 135 mg of zinc daily. Some evidence suggests that a lower and safer dose, 30 mg daily, may offer some benefits. In some studies, however, no benefits were seen.

Two studies have compared zinc against a standard treatment for acne, the antibiotic tetracycline. One study found that zinc was as effective as tetracycline taken at 250 mg daily, but another found the antibiotic far more effective when taken at 500 mg daily.

Keep in mind that the dosages of zinc used in most of these studies are rather high; case reports indicate that people have made themselves extremely ill by taking zinc in the hope of treating their acne symptoms. Doses of zinc higher than the recommended safe levels should be used only under a physician’s supervision.

Sickle cell disease. Children with sickle cell
disease often do not grow normally. There is some evidence
that people with sickle cell disease are more likely than others to be deficient
in zinc. Since zinc deficiency can also cause delayed growth, zinc supplementation
at nutritional doses has been suggested for children with sickle cell disease. In
a placebo-controlled study, forty-two children (aged four to ten) with sickle cell
disease were given either zinc supplements (10 mg of zinc daily) or placebo for a
period of one year. Results showed that by the end of the study, the participants
given zinc showed enhanced growth compared with those given placebo. Curiously,
researchers did not find any solid connection between the severity of zinc
deficiency and the extent of response to treatment.

Zinc is thought to have a stabilizing effect on the cell membrane of red blood cells in people with sickle cell disease. For this reason, it has been tried as an aid for preventing sickle cell crisis. In a double-blind, placebo-controlled study of 145 people with sickle cell disease conducted in India, participants received either placebo or about 50 mg of zinc three times daily. During eighteen months of treatment, the zinc-treated subjects had an average of 2.5 crises, compared with 5.3 for the placebo group. However, zinc did not seem to reduce the severity of a crisis, as measured by the number of days spent in the hospital for each crisis.

Sickle cell disease can also cause skin ulcers (nonhealing sores). In a twelve-week, placebo-controlled trial, use of zinc at 88 mg three times per day for twelve weeks enhanced the rate of ulcer healing.

The high dosages of zinc used in the last two studies can cause dangerous toxicity and should be taken (if at all) only under the supervision of a doctor. The nutritional dose described in the first study, however, is safe.

Safety Issues

Zinc taken orally seldom causes any immediate side effects other than occasional
stomach upset, usually when it is taken on an empty stomach. Some forms do have an
unpleasant metallic taste. Use of zinc nasal gel, however, has been associated
with anosmia (loss of sense of smell). In fact, after receiving
more than 130 reports of anosmia, the U.S. Food and Drug Administration (FDA)
warned consumers and health care providers in 2009 to discontinue use of certain
Zicam Cold Remedy intranasal zinc-containing products, including Zicam Cold Remedy
nasal gel, Cold Remedy nasal swabs, and Cold Remedy swabs in children’s size.
Furthermore, if the gel is inhaled too deeply, severe pain may occur.

Long-term use of oral zinc at dosages of 100 mg or more daily can cause a number of toxic effects, including severe copper deficiency, impaired immunity, heart problems, and anemia. Zinc at a dose of more than 50 mg daily might reduce levels of high-density lipoprotein (HDL, or good) cholesterol. In addition, very weak evidence hints that use of zinc supplements might increase risk of prostate cancer in men.

The U.S. government has issued recommendations regarding tolerable upper intake levels (ULs, in milligrams, or mg) for zinc. The UL can be thought of as the highest daily intake over a prolonged time known to pose no risks to most members of a healthy population. The ULs for zinc are as follows:

Infants aged 0 to 6 months (4 mg) and 7 to 12 months (5 mg); children aged 1 to 3 years (7 mg), 4 to 8 years (12 mg), 9 to 13 years (23 mg), and 14 to 18 years (34 mg); adults (40 mg); pregnant and nursing girls (34 mg); and pregnant and nursing women (40 mg).

Some interactions occur between zinc and certain medications. For example, the use
of zinc can interfere with the absorption of the drug penicillamine
and also with antibiotics in the tetracycline or fluoroquinolone (Cipro, Floxin) families.

The potassium-sparing diuretic amiloride was found to significantly reduce zinc excretion from the body. This means that if people take zinc supplements at the same time as amiloride, zinc accumulation could occur, which could lead to toxic side effects. However, the potassium-sparing diuretic triamterene does not seem to cause this problem.

Important Interactions

People who are using ACE inhibitors, estrogen-replacement therapy, oral contraceptives, thiazide diuretics, or medications that reduce stomach acid (such as H2 blockers [Zantac] or proton pump inhibitors [Prilosec]) may need to take extra zinc. In addition, the diuretic amiloride could reduce zinc excretion from the body, leading to zinc accumulation, which could cause toxic side effects. People using amiloride should not take zinc supplements unless advised by a physician.

It may be advisable for people taking manganese, calcium, copper, iron, antacids, soy, or antibiotics in the fluoroquinolone (such as Cipro or Floxin) or tetracycline families to separate their doses of zinc and these substances by at least two hours. Zinc also interferes with penicillamine’s absorption, so it may be advisable for people to take zinc and penicillamine at least two hours apart.

Finally, people who are using zinc supplements should also take extra copper and perhaps magnesium because zinc interferes with their absorption. Zinc interferes with iron absorption, too, but people should not take iron supplements unless they know they are deficient.

Bibliography

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Carcamo, C., et al. “Randomized Controlled Trial of Zinc Supplementation for Persistent Diarrhea in Adults with HIV-1 Infection.” Journal of Acquired Immune Deficiency Syndromes 43, no. 2 (2006): 197-210.

Ebisch, I. M., et al. “Does Folic Acid and Zinc Sulphate Intervention Affect Endocrine Parameters and Sperm Characteristics in Men?” International Journal of Andrology 29 (2006): 339-345.

Eby, G. A., and W, W. Halcomb. “Ineffectiveness of Zinc Gluconate Nasal Spray and Zinc Orotate Lozenges in Common-Cold Treatment.” Alternate Therapies in Health and Medicine 12 (2006): 34-38.

Halyard, M. Y., et al. Does Zinc Sulfate Prevent Therapy-Induced Taste Alterations in Head and Neck Cancer Patients? Results of Phase III Double-Blind, Placebo-Controlled Trial from the North Central Cancer Treatment Group (N01C4).” International Journal of Radiation Oncology, Biology, Physics 67 (2007): 1318-1322.

Kurugol, Z., N. Bayram, and T. Atik. “Effect of Zinc Sulfate on Common Cold in Children.” Pediatrics International: Official Journal of the Japan Pediatric Society 49 (2007): 842-847.

Lazzerini, M., and L. Ronfani. “Oral Zinc for Treating Diarrhoea in Children.” Cochrane Database of Systematic Reviews 3 (2008): CD005436.

Lin, L. C., et al. “Zinc Supplementation to Improve Mucositis and Dermatitis in Patients After Radiotherapy for Head-and-Neck Cancers.” International Journal of Radiation Oncology, Biology, Physics 65 (2006): 745-750.

Maylor, E. A., et al. “Effects of Zinc Supplementation on Cognitive Function in Healthy Middle-Aged and Older Adults.” British Journal of Nutrition 96 (2006): 752-760.

Patro, B., D. Golicki, and H. Szajewska. “Meta-analysis: Zinc Supplementation for Acute Gastroenteritis in Children.” Alimentary Pharmacology and Therapeutics 28, no. 6 (2008): 713-723.

Prasad, A. S., et al. “Zinc Supplementation Decreases Incidence of Infections in the Elderly: Effect of Zinc on Generation of Cytokines and Oxidative Stress.” American Journal of Clinical Nutrition 85 (2007): 837-844.

Singh, M., and R. R. Das. “Zinc for the Common Cold.” Cochrane Database of Systematic Reviews 2 (2011): CD001364.

Is there any use of personification?

Yes. In fact, Sonnet 65 is brimming with personification! Here are all the instances of this particular device that we see in the poem:

1. "sad mortality"

The speaker is attributing a human emotion, sadness, to the nonhuman concept of mortality.

2. "How with this rage shall beauty hold a plea"

Here, the idea is that beauty might be able to plea, or beg. That's a human activity, again attributed to an abstract concept: beauty.

...

Yes. In fact, Sonnet 65 is brimming with personification! Here are all the instances of this particular device that we see in the poem:

1. "sad mortality"

The speaker is attributing a human emotion, sadness, to the nonhuman concept of mortality.

2. "How with this rage shall beauty hold a plea"

Here, the idea is that beauty might be able to plea, or beg. That's a human activity, again attributed to an abstract concept: beauty.

3. "summer's honey breath hold out"

The speaker personifies the summer, saying it has "breath" (which is something that humans have, not periods of time).

4. "the wreckful siege of battering days"

Saying that days can siege someone is another instance of personification: it's giving the human power of fighting a war or launching an attack to the nonhuman concept of "days."

5. "Or what strong hand can hold his swift foot back?"

In the line above, "his" means "Time's." The line personifies "Time," saying it has a swift foot, like a human might have.

You might point to a few more examples of personification in this poem, such as in the line that implies that Time has the power to decay--but to me, these examples stray a bit too far from the definition of personification to be properly characterized as examples of it. "Decaying" is something that happens to us, rather than some activity that we ourselves put into effect. So whether or not you interpret that line as personification is a matter of personal perspective.

Overall, as you can see, Shakespeare's use of personification throughout this poem gives it a grand, dramatic tone, and it helps us imagine the forces of nature and human beauty as timeless, powerful entities.

In "A Very Old Man with Enormous Wings," is the man an angel or a human being?

It is really impossible to say if the man is an angel or a human being. The title of the story implies that he is indeed a man with wings; but the story and the symbolism behind the man resist interpretation. He is described as everything from an angel to a sailor. He is depicted as a buzzard and a hen "among the fascinated chickens." To some, he should be "the mayor of the world,"...

It is really impossible to say if the man is an angel or a human being. The title of the story implies that he is indeed a man with wings; but the story and the symbolism behind the man resist interpretation. He is described as everything from an angel to a sailor. He is depicted as a buzzard and a hen "among the fascinated chickens." To some, he should be "the mayor of the world," and to others a "five-star general." The old man with wings is interpreted in many ways by the villagers and there is no final verdict. At the end of the story, he flies away and is seen as nothing more than "an imaginary dot on the horizon."

There is no explanation for what the old man is or how he came to be. He does not respond to the villagers questions and cannot speak. In contrast, the spider woman who comes to town is able to explain her predicament clearly, and her story has a moral. Her story is "full of so much human truth."

Unlike the spider woman who can be understood so easily, the old man has no explanation. The villagers, though initially fascinated by the old man, soon neglect him and flock to the spider woman. Like the old man, Garcia Marquez's magical realism resists interpretation and is a departure from more straightforward and easily understood literature.

Why does the Earth spin?

There are various phenomena that are caused by movement of heavenly bodies. We observe different seasons throughout the year because the earth is at different positions relative to the sun as it revolves around it. Tides are caused by the relative position of the earth and the moon. Similarly, day and night are caused by the earth's rotation. But why is the earth spinning?

Earth, and other planets, rotate about their axis - or spin...

There are various phenomena that are caused by movement of heavenly bodies. We observe different seasons throughout the year because the earth is at different positions relative to the sun as it revolves around it. Tides are caused by the relative position of the earth and the moon. Similarly, day and night are caused by the earth's rotation. But why is the earth spinning?

Earth, and other planets, rotate about their axis - or spin - due to inertia. Inertia is the tendency of objects at rest to stay at rest, or to move at a constant rate when they're moving unless external force is applied. Hence, the earth is spinning because it was spinning when it was formed, and has just continued to do so due to inertia.

To understand why it started spinning in the first place, one has to go back to the birth of the entire solar system. Dust and gas are what started everything. The cloud began to collapse and the gravity in the center started pulling things in as it collapsed, compacting dust and gas forming stars-- and planets. As this happened, the formed bodies started spinning faster. There was angular momentum, or the tendency of objects to spin. Hence, when earth was formed, it was spinning, and it hasn't stopped since.

Interestingly, it is believed that the earth hasn't always spun at the same rate. It was slower. However, it was hit by a large object - which ultimately caused the formation of the moon - and increasing the earth's speed in the process.

What is colostomy? |

Cancers diagnosed or treated: Colon cancer, rectal cancer, advanced anal cancer

Why performed: Colostomy is performed to reroute the waste in the colon, either as a temporary diversion or as a permanent new path for waste to leave the body. Temporary diversion may be needed so that newly connected tissues in the lower bowel can heal, to stage an operation for a patient who has a partial obstruction or is too frail to undergo extensive surgery, or in an emergency to relieve an obstructing tumor or to allow an infection to clear before removing diseased tissue. Later, the temporary ostomy may be reversed to restore normal bowel function. Permanent colostomy is needed when the anal sphincter is removed, when the rectum and part or all of the colon are removed and it is not possible or optimal to connect the remaining ends, or when an obstructing tumor cannot be bypassed or an unremovable tumor is likely to obstruct.

Patient preparation: A series of medical tests are completed to plan treatment and to evaluate the patient’s fitness for this surgery. A specialist (ostomy nurse or enterostomal therapist) counsels the patient and helps choose the location for the stoma. For the procedure, certain patient medications may need to be stopped, the patient’s bowel must be cleaned, and the patient’s stomach must be empty. In an emergency, patient evaluation and preparation may be limited.

Steps of the procedure: Colostomy is performed in a hospital as part of or as the first stage of a larger operation. For the procedure, sensors are placed to monitor the patient’s condition. An intravenous (IV) line is started, and an antibiotic is infused. General anesthesia is administered, and a breathing tube is placed. The patient is positioned, a urinary catheter is inserted, and the incision sites are prepared.

Most commonly, a colostomy constructs either an end-type or a loop-type stoma. Details for each procedure vary with the larger operation needed, the parts of the bowel involved, and the surgical approach chosen (open or laparoscopic).

With an end-type stoma, this procedure temporarily or permanently connects the upper end of the colon to an opening on the abdomen. First, an ostomy opening is made in the abdomen. The colon is freed from attachments and divided. The upper end is passed through the ostomy opening, the colon segment is sized to an appropriate length, and the edge of the cut end is folded back and stitched to the abdomen, forming an end stoma. The lower end may be totally removed, permanently sealed, temporarily sealed, or temporarily formed into a mucous fistula by connecting it to a second abdominal opening.

With loop-type stoma, this procedure temporarily opens a loop of colon onto the abdomen and constructs either one stoma (end-loop) or two stomas (double-barrel). First, an ostomy opening is made in the abdomen. A loop of colon is freed from attachments and is brought through the ostomy opening. Then, either an end-loop stoma or a double-barrel stoma is constructed. To construct an end-loop stoma, the loop is divided. The lower end is sealed and anchored with one stitch near the ostomy opening, and the cut edge of the upper end is folded back and stitched to the abdomen, forming one stoma. To construct a double-barrel stoma, the loop is slit lengthwise. A small bridge is placed underneath the loop, bisecting the slit and raising the middle of the loop. The edges of the split are stitched to the abdomen on both sides of the bridge, forming two stomas.

After the procedure: After the surgery, anesthesia is stopped, and the breathing tube is removed. The urinary catheter and the IV line are kept. A clear collection pouch is fitted over the stoma. The patient is transferred to the recovery room and then to a hospital room. Medications are given to control pain and infection. The ostomy is closely monitored; once it starts functioning, the patient learns how to care for the stoma, empty and change pouches, and manage bowel function. At home, the patient follows the physician’s instructions for medications, activities, and diet.

Risks: Colostomy is relatively safe. Stomal side effects are very common, but most are not serious. Early side effects are irritation and leakage. Later side effects are hernia, prolapse, fistula, obstruction, ischemia, necrosis, retraction, separation, and narrowing. When an ostomy is temporary, overall risk includes that of reversing the colostomy.

Results: After colostomy, waste previously collected in the rectum and pushed through the anus now flows through the ostomy into a flat plastic pouch (ostomy appliance) that fits securely over the stoma. Many types and sizes of ostomy appliances are available, depending on the type of colostomy and patient-specific factors. Some patients benefit from minor changes in diet and alterations in clothing. All patients can perform the same activities as before. Over the years, patients’ quality of life has greatly improved with advances in ostomy management and stomal care.

Backes, Marli Terezinha Stein, Dirce Stein Backes, and Alacoque Lorenzini Erdmann. "Feelings and Expectations of Permanent Colostomy Patients." Journal of Nursing Education and Practice 2.3 (2012): 9–14. Print.

Fleshman, Jr., James W., et al. Atlas of Surgical Techniques for the Colon, Rectum, and Anus. Philadelphia: Saunders-Elsevier, 2012. Print.

Levin, Bernard, et al., eds. American Cancer Society’s Complete Guide to Colorectal Cancer. Atlanta: Amer. Cancer Soc., 2006. Print.

Recalla, Stacy, et al. "Ostomy Care and Management: A Systematic Review." Journal of Wound, Ostomy and Continence Nursing 40.5 (2013): 489–500. Print.

Scholefield, John and Cathy Eng, eds. Colorectal Cancer: Diagnosis and Clinical Management. Hoboken: Wiley, 2014. Print.

What is hormone therapy? |

Indications and Procedures

During a woman’s reproductive years, a complex feedback loop among the hypothalamus, pituitary gland, and ovaries causes the ovaries to produce various sex hormones, the major ones being estrogens and progesterone. These hormones are responsible for developing the secondary sexual characteristics such as breasts and pubic hair, for governing the menstrual cycle, and for maintaining a pregnancy should one occur. They also have profound effects on a woman’s skin, heart, blood vessels, lipids (blood fats such as cholesterol), bones, blood, and other systems.

As women approach menopause, changes begin to occur in the hormone feedback loop. The menstrual cycle typically becomes shorter and more irregular, and then menses cease altogether. As hormone levels decline and the ratio between the estrogens and progesterone changes, the woman’s body undergoes other changes such as thinning of the mucous membranes in the reproductive and urinary tract, drying of the skin, thinning of the bones, and alterations in cholesterol levels. Perimenopausal women may also experience hot flashes, night sweats, insomnia, mood swings, and other uncomfortable symptoms. Postmenopausal women do continue to produce sex hormones, although in smaller amounts. The adrenal glands are responsible for much of the postmenopausal hormone production, and some production occurs by conversion of other hormones in the body tissues.

Menopause normally occurs between the ages of forty-five and fifty-five, with an average age of about fifty-one. Menopause before the age of forty is called "premature menopause." A woman who stops menstruating because of a total hysterectomy, in which not only the uterus but also the Fallopian tubes and ovaries are removed, undergoes what is called a "surgical menopause." Women who undergo radiation of the ovaries also experience an artificial menopause. The discomforts associated with menopause may be exaggerated in these women.

Health care providers have used hormone therapy, formerly called "hormone replacement therapy (HRT)," to treat uncomfortable perimenopausal symptoms and to prevent or treat a number of conditions associated with the postmenopausal state. Hormone therapy may include estrogen alone or a combination of estrogen and progesterone. At times, other hormones such as testosterone may be used to treat symptoms, but it is the estrogen-progesterone combination that constitutes what is commonly thought of as hormone therapy. Estrogen therapy is the use of estrogen alone and was formerly known as "estrogen replacement therapy (ERT)."

Hormone therapy may also be prescribed to manage conditions that cause menorrhagia (heavy menstrual bleeding), such as uterine fibroids (noncancerous growths in the uterus), endometriosis (monthly growth of the uterine lining tissue outside the uterus), and ovarian cysts. The long-term risks and contraindications are similar to those for perimenopausal and menopausal women.

Uses and Complications

A variety of estrogens and progestogens are available for the treatment of menopausal symptoms. They include oral estrogens and progestin, transdermal estrogens, injectable estrogens and progestins, and topical estrogens. Oral estrogens for hormone therapy include conjugated estrogens, micronized estradiol, piperazine estrone sulfate, ethinyl estradiol, and quinestrol. Of these, the conjugated equine estrogens have been most extensively studied over a long period of time. They are usually well tolerated by patients. Various estrogens are also available as transdermal patches, inhalable sprays, or vaginal creams or rings. Various combination products are available to administer estrogen with a progestin, including oral and transdermal formulations. Progesterone may be supplied by oral progestins, oral progesterone, topical vaginal preparations, subdermal implants, and levonorgestrel-containing IUDs.

In the 1990s, clinicians provided hormone therapy (then called "hormone replacement therapy") to prevent osteoporosis and heart attacks; the hormone therapy relieved vaginal dryness and hot flashes as well. It was thought that hormone therapy would also provide a number of other benefits for conditions ranging from mood swings to insomnia to prevention of Alzheimer’s disease. At various times throughout the twentieth century, health care providers and researchers recommended that all women in perimenopause begin hormone therapy.

In 1998, results from a large clinical trial, the HERS study (Heart and Estrogen/Progestin Replacement Study), which enrolled women with existing heart disease, demonstrated an unanticipated increase in heart attacks for women in the first year of medication; furthermore, there was no cardiac benefit in the years to follow. In 2002, the Women’s Health Initiative (WHI) published groundbreaking results of a large study of women on estrogen and progestin; the trial was ended early because of safety concerns. Findings included blood clots and an increased risk for breast cancer, but a decrease in colon
cancer and osteoporotic fractures. Researchers concluded that the risks of taking the medications were not worth the benefits.

A subsequent study of estrogen alone was stopped early because of a small increase in stroke risk. Research has also shown that women using estrogen-only treatments are at higher risk of developing coronary heart disease. Major medical organizations now recommend that hormone therapy should be used only in the smallest effective dose, for the shortest effective period of time, and only for relief of severe symptoms, primarily hot flashes. Hormone therapy should not be used only to prevent osteoporosis.

Women who take estrogen supplementation without a progestogen are at increased risk for developing excessive thickening of the lining of the uterus. This situation can ultimately result in carcinoma (cancer) of the uterus. The development of ovarian cancer is also possible. For this reason, women who have not had a hysterectomy are advised to take only estrogen with concomitant provision of progestogens. If the combination is given on a cyclical basis, however, the woman will most likely experience monthly withdrawal bleeding. This is not always acceptable to postmenopausal women. Most women who take a continuous dose of a lower-dose progestogen will not bleed at all after a year of its continuous use; the remainder will bleed occasionally.

Women who take oral estrogen supplements have an increased tendency to develop blood clots. This risk is greatly decreased with transdermal formulations. Estrogen therapy is also associated with an increased risk of gallbladder disease.

Women who should not take estrogen-containing hormones at all include those with unexplained vaginal bleeding, a history of uterine or breast cancer, liver disease, or a history of blood clots in the veins. Hormone therapy should be used with caution in women with seizure disorders, high blood pressure, diabetes mellitus, migraines, gallbladder disease, and certain other conditions. Minor adverse effects of hormone treatment include swelling, breast tenderness, bloating, headaches, and increased cervical mucus.

As the supply of estrogen decreases, women experience thinning and drying of the vaginal tissues. The cervix, uterus, and ovaries become smaller in size, and the cervix stops producing mucus. In addition, the ligaments that support the reproductive organs become more relaxed. These changes may lead to painful sexual intercourse, bleeding with minor trauma, itching, vaginal discharge, and prolapse of the uterus. Topical vaginal formulations, rather than oral, systemic medications, are recommended if only vaginal thinning and dryness are indicated, .

The tissues of the bladder and urethra also become thinner, which may lead to urinary urgency, painful urination, or increased frequency. Some women even become incontinent. The evidence is not entirely clear about the usefulness of estrogen in this setting.

Vasomotor instability refers to the changes that lead to hot flashes and increased sweating. These flashes may be accompanied by heart palpitations, weakness, fatigue, dizziness, or lightheadedness. The episodes may cause nighttime awakening or insomnia, which in turn may lead to memory problems or irritability. The major treatment for vasomotor instability is the administration of estrogen, although progestogens have been used in women who cannot take estrogen. Some women find relief from a different type of drug called clonidine. Other treatments, which have not been studied as thoroughly as estrogen and progesterone, include various vitamin and mineral supplements, tranquilizers, and antidepressants.

All people gradually lose bone mass as they age, but in the years following menopause, this process accelerates in women, particularly in the type of bone known as "trabecular bone." Postmenopausal women’s risk for hip fracture becomes two to three times that of men. For this reason, estrogen has been recommended in the past for prevention of osteoporosis, particularly in women who are thin, who smoke cigarettes, who have a strong family history of osteoporosis, who drink large amounts of alcohol, or who have some other risk factor. With concerns about the safety of estrogens, however, other drugs are increasingly used to prevent or treat osteoporosis, including drugs from the classes known as bisphosphonates and selective estrogen receptor modulators (SERMs). Calcitonin and progestogens may also be used, but they do not seem to be as effective as the estrogens, bisphosphonates, or SERMs. All menopausal women should probably take supplemental calcium and vitamin D, exercise regularly, stop smoking if needed, and limit alcohol, caffeine, salt, and animal proteins to minimize their risk of developing osteoporosis.

Before menopause, very few women have heart attacks. This state changes rapidly after menopause, and by age seventy, women have the same risk of heart attack as men. However, major medical organizations have recommended that combination therapy not be used for the prevention of cardiac disease.

As people age, they experience changes in the skin and hair.
The skin becomes thinner and less elastic, particularly in sun-exposed areas. There is some loss of pubic hair and hair in the armpits. Some women experience balding, and some develop coarse facial hair. Body hair may either increase or decrease. The skin has estrogen receptors, so those changes are thought to be caused by decreased estrogen. Hair changes are more likely to result from a change in the ratio of estrogen to testosterone in the body after menopause. Testosterone levels remain nearly the same before and after menopause, while estrogen levels drop drastically. Topical hormones have been used to ameliorate or prevent skin changes, especially vaginal atrophy and dryness; however, use of systemic hormones is not supported for these indications.

Some studies have found that women in early menopause experience more irritability, depression, and feelings of anxiety. It is not clear if these changes are attributable to some change in brain chemistry as a result of decreased estrogen, to societal expectations about aging, or to some other factor. Some researchers have suggested that the lack of sleep caused by hot flashes and night sweats, rather than menopause itself, is the source of mood changes. Furthermore, many perimenopausal women have multiple stressors, such as caring for aging parents, which may contribute to depression and anxiety. In contrast to past practice, current evidence does not support the use of hormone therapy for depression or prevention of Alzheimer’s disease and other dementias.

In summary, the only indication for systemic hormone administration is for severe menopausal symptoms at the lowest possible dose for the shortest period of time; those with abnormal bleeding conditions should discuss the long-term risks of hormone therapy with their clinicians. Topical preparations may be used for indications such as vaginal dryness or discomfort.

A.D.A.M. Medical Encyclopedia. "Hormone Therapy." MedlinePlus, September 13, 2011.

American College of Obstetricians and Gynecologists. "Hormone Therapy." American Congress of Obstetricians and Gynecologists, 2013.

American Society of Health-System Pharmacists. "Estrogen and Progestin (Hormone Replacement Therapy)." MedlinePlus, August 1, 2010.

Love, Susan, and Karen Lindsey. Dr. Susan Love’s Menopause and Hormone Book: Making Informed Choices. Rev. ed. New York: Random House, 2003.

National Women’s Health Network. The Truth about Hormone Replacement Therapy: How to Break Free from the Medical Myths of Menopause. Roseville, Calif.: Prima, 2002.

Rull, Gurvinder. "Progestogens." Patient.co.uk, April 20, 2011.

Seaman, Barbara. The Greatest Experiment Ever Performed on Women: Exploding the Estrogen Myth. New York: Seven Stories Press, 2009.

Scholten, Amy, and Brian Randall. "Hormone Replacement Therapy: A Look at the Options." Health Library, August 16, 2012.

What is a vegetarian diet?

Overview

A vegetarian diet has many health benefits and may actually reduce the incidence of some diseases. The American Dietetic Association (ADA) states that properly managed vegetarian diets “are healthful, nutritionally adequate, and provide health benefits in the prevention and treatment of certain diseases.”

The defining characteristic of a vegetarian diet is abstention from meat consumption. There are, however, a number of different types of vegetarian diets, ranging from the lacto-ovo vegetarian diet, which includes dairy products and eggs, to the vegan diet, which excludes all meats and animal products. The focus here is the lacto-ovo vegetarian diet.

Mechanism of Action

A vegetarian diet works through eliminating the consumption of meat products that are high in saturated fat and cholesterol, while increasing the intake of high-fiber, cholesterol-free, plant-based foods.

Uses and Applications

The transition to a healthy vegetarian diet can be simple with some education and planning. A healthy vegetarian diet centers on decreasing fat intake and increasing fiber intake. This can be accomplished through emphasizing fresh fruits and vegetables, beans and other legumes, and whole-grain foods that are high in fiber and low in cholesterol and saturated fat. The diet avoids processed foods and refined sugar. A healthy vegetarian diet fulfills all these criteria.

Many nutritionists, however, recommend that a person transition to a vegetarian diet in stages, allowing the body to adjust by substituting a few meat meals each week with vegetarian food. One should start by reducing and eliminating red meat, then gradually eliminating pork, poultry, and fish. A simple way to make the transition is to use readily available soy-based meat substitutes such as tofu, tempeh, and textured vegetable protein, which are high in protein and can have a meat-like texture and taste.

In 2003, the ADA published a set of guidelines for North American vegetarian diets, recommending the following elements:

Whole grains. Six servings per day, including wheat, oatmeal, quinoa, couscous, and rice. Grains provide fiber, iron, and B vitamins. If possible, one should soak grains overnight to increase their digestibility.

Vegetables and fruits. Six servings per day, including carrots, leafy greens, collards, brassicas (broccoli, cabbage, brussels sprouts), apples, oranges, and bananas. Brassicas are rich in vitamin C, fiber, and carotenoids. Leafy greens and collards are sources of calcium, protein, and many vitamins, including C and A. Fruits are rich in vitamins B and C and calcium. Fresh vegetables and fruits have the highest vitamin content. One should steam or lightly cook vegetables to maintain higher nutrient value.

Legumes, nuts, and other protein-rich foods. Five servings per day, including beans, peas, soy, nuts, dairy foods, and eggs.

Fats. Two servings per day, including vegetable oils, walnuts, mayonnaise, butter, and margarine.

Calcium-rich foods. Eight servings per day, including milk, cheese, fortified soy and fruit juices, and leafy greens.

Scientific Evidence

Research has shown that people who eat a healthy vegetarian diet weigh less and have lower cholesterol levels, lower blood pressure, and lower rates of many diseases. Research also has shown that this diet can reverse the effects of atherosclerosis. The risk of men contracting prostate cancer and women getting breast cancer are almost four times as high for meat eaters, compared with those on a largely vegetarian diet. In addition, a vegetarian diet has been used successfully to treat osteoporosis, arthritis, allergies, asthma, gout, hemorrhoids, kidney stones, premenstrual syndrome, anxiety, and depression. A 2000 study of members of the Seventh-day Adventist Church (who practice a lacto-ovo vegetarian diet) indicated that these members live, on average, two years longer than persons on a meat-based diet.

In 2014, a study published in the Journal of the American Medical Association: Internal Medicine confirmed the connection between vegetarianism and lower blood pressure through a new meta-analysis of all previous studies conducted on the subject. The researchers reported that their analysis suggested that a vegetarian diet is about half as strong as taking medication in terms of keeping blood pressure down. Neal Barnard, one of the lead researchers of the study, also stated that he believes those who consume meat and subsequently animal fat have higher blood viscosity that leads to higher blood pressure.

Safety Issues

A well-planned vegetarian diet is a healthy and safe diet; however, vegetarians need to be aware of particular nutrients that may be lacking in diets without meat. These nutrients include protein, vitamin B12, vitamin A, vitamin D, calcium, iron, zinc, and N-3 fatty acids. It is possible to get these nutrients from plant-based foods, but they are not as abundant as in animal-based foods. To reap the benefits of a vegetarian diet, it is important to eat a diverse mix of whole grains, fresh vegetables, fruits, leafy greens, legumes, and nuts and to consciously reduce cholesterol and saturated fat intake by limiting dairy, eggs, and high-fat foods.

Animal-based proteins are complete proteins but are high in cholesterol. Research has shown that plant sources can meet the body’s need for protein as long as a variety of plant foods are consumed. Most plant proteins are incomplete, lacking one or more of the essential amino acids. However, vegetarians can easily overcome this lack by combining a variety of complementary plant sources. In general, combining legumes such as beans, soy, and peas with grains such as rice, wheat, and couscous (for example, in beans and rice, hummus and crackers, or peanut butter and bread) forms a complete protein.

Those vegetarians who regularly eat eggs and dairy foods get adequate amounts of vitamin B12
, yet the ADA recommends regular B12 supplements or foods fortified with B12. Vitamin A requirements can be met through eating carrots, leafy greens, or fruits (such as apricots, mangos, and pumpkins) that are rich in beta-carotene or by taking supplements. Vegetarians can get adequate amounts of vitamin D through regular exposure to the sun, by eating fortified foods, and by taking supplements.

Calcium is readily obtained by eating enriched soy products, nuts, legumes, dairy, and dark green vegetables such as broccoli and kale. Iron is available in raisins, legumes, tofu, potatoes, and leafy greens. Iron is absorbed more efficiently in the body if iron-rich foods are combined with those containing vitamin C, such as oranges, apples, and tomatoes. Zinc is abundant in pumpkin seeds, legumes, peas, lentils, whole grains, and soy products.

Vegetarians need to get adequate amounts of N-3 or omega-3 fatty acids. Vegetarian diets tend to be high in N-6 fatty acids but low in N-3 fatty acids (found in abundance in seafood and in some plants and nut oils). The body needs a balance of both. Vegetarian sources of N-3 fats include soy, walnuts, pumpkin seeds, and hemp seeds. Flaxseed oil is particularly rich in these fats.

Bibliography

Freston, Kathy. "Why Do Vegetarians Live Longer?" Huffington Post. TheHuffingtonPost.com, 26 Dec. 2012. Web. 28 Jan. 2016.

Hagler, Louise, and Dorothy R. Bates, eds. The New Farm Vegetarian Cookbook. 2nd ed. Summertown: Book, 1989. Print.

Hamblin, James. "Vegetarians and Their Superior Blood." Atlantic. Atlantic Media Group, 24 Feb. 2014. Web. 28 Jan. 2016.

“A New Food Guide for North American Vegetarians.” Available at http://www.metabolicdiet.com/pdfs/veg_food_guide.pdf. Outlines the basics of a balanced and healthy vegetarian diet.

Whoriskey, Peter. "Is a Vegetarian Diet Really Better for the Environment? Science Takes Aim at the Conventional Wisdom." Washington Post. Washington Post, 18 Dec. 2015. Web. 28 Jan. 2016.

What are natural treatments for sickle cell disease?

Introduction

Sickle cell
disease is an inherited blood disorder. Normally, red blood
cells are disc-shaped and flexible. In sickle cell disease, however,
hemoglobin (the chemical within red blood cells that carries
oxygen around the body) is abnormal. This defect causes red blood cells to
collapse into a crescent, or sickle, shape.

These abnormal blood cells are destroyed at an unusually high rate, causing a
shortage of red blood cells (anemia). In addition, they can suddenly
clump together and clog up small blood vessels throughout the body. This clumping
causes what is called a sickle cell crisis. When blood vessels are blocked by
sickle-shaped red blood cells, parts of the body are deprived of oxygen. This can
cause severe pain and damage to the organs and tissues that are deprived.

Sickle Cell Disease

The red blood cells are sickle-shaped rather than round, which causes blockage of
capillaries.

The common triggers of sickle cell crisis include smoking, exercise, exposure to
high altitudes, fever, infection, dehydration, and the drop in oxygen and changes
in air pressure that can occur during air travel. Diagnosis of sickle cell disease
and sickle cell trait (a condition in which a person has one of the two genes
necessary to develop sickle cell disease) can be done through blood testing, using
a technique called hemoglobin electrophoresis.

Treatment involves managing the anemia, chronic pain, and organ damage caused by
sickle cell disease. In addition, the drug hydroxyurea can reduce occurrences of
sickle cell crisis. It is also important to minimize exposure to conditions or
situations that can trigger sickle cell crisis.

Principal Proposed Natural Treatments

Children with sickle cell disease often do not grow normally. Zinc deficiency can
also cause growth retardation, and there is some evidence that people with sickle
cell disease are more likely than others to be deficient in the mineral zinc. For
this reason, zinc supplementation at nutritional doses has been suggested
for children with sickle cell disease.

In a placebo-controlled study, forty-two children (aged four to ten years) with sickle cell disease were given either zinc supplements (10 milligrams [mg] of zinc daily) or placebo for one year. Results showed that by the end of the study, the participants given zinc showed enhanced growth compared to those given placebo. Curiously, researchers did not find any solid connection between the severity of zinc deficiency and the extent of response to treatment.

Zinc is thought to have a stabilizing effect on the cell membrane of red blood cells in people with sickle cell disease. For this reason, it has been tried as an aid for preventing sickle cell crisis. In a double-blind, placebo-controlled study of 145 people with sickle cell disease conducted in India, participants received either placebo or about 50 mg of zinc three times daily. During eighteen months of treatment, the zinc-treated subjects had an average of 2.5 crises, compared to 5.3 crises for the placebo group. However, zinc did not seem to reduce the severity of a crisis, as measured by the number of days spent in the hospital for each crisis.

Sickle cell disease can also cause skin ulcers (nonhealing sores). In a twelve-week, placebo-controlled trial, the use of zinc at 88 mg three times per day enhanced the rate of ulcer healing. In another placebo-controlled trial, 25 mg of zinc three times per day for three months reduced the frequency of infections in children with sickle cell disease.

The high dosages of zinc used in the last two studies can cause dangerous toxicity and should be taken only under the supervision of a doctor. The nutritional dose described in the first study, however, is safe.

Other Proposed Natural Treatments

A year-long, double-blind, placebo-controlled, crossover study of eighty-two
people with sickle cell disease tested a combination herbal treatment made from
plants indigenous to Nigeria. The results indicate that the use of the herbal
mixture reduced the incidence of sickle cell crisis. A small, double-blind,
placebo-controlled trial found intriguing evidence that fish oil may
reduce the frequency of painful sickle cell episodes, possibly by reducing the
tendency of the blood to clot.

Also suggested for people with sickle cell disease are numerous other herbs and supplements, including alpha-linolenic acid, beta-carotene, coenzyme Q10, folate, garlic, green tea, lipoic acid, magnesium, oligomeric proanthocyanidins, suma, and vitamins B2, B6, B12, C, and E, but the supporting evidence for these treatments remains far too preliminary to be relied upon.

Bibliography

Ballas, S. K. “Hydration of Sickle Erythrocytes Using a Herbal Extract (Pfaffia paniculata) In Vitro.” British Journal of Haematology 111 (2000): 359-362.

Bao, B., et al. “Zinc Supplementation Decreases Oxidative Stress, Incidence of Infection, and Generation of Inflammatory Cytokines in Sickle Cell Disease Patients.” Transl Res. 152 (2008): 67-80.

Ohnishi, S. T., T. Ohnishi, and G. B. Ogunmola. “Sickle Cell Anemia: A Potential Nutritional Approach for a Molecular Disease.” Nutrition 16 (2000): 330-338.

Tomer, A., et al. “Reduction of Pain Episodes and Prothrombotic Activity in Sickle Cell Disease by Dietary N-3 Fatty Acids.” Thrombosis and Haemostasis 85 (2001): 966-974.

Zemel, B. S., et al. “Effect of Zinc Supplementation on Growth and Body Composition in Children with Sickle Cell Disease.” American Journal of Clinical Nutrition 75 (2002): 300-307.

What is pigmentation? |

Structure and Functions

One of the most apparent human characteristics is the color of a person’s skin. Five pigments play major roles: melanin, melanoid, carotene, hemoglobin, and oxyhemoglobin. Melanin occurs in the greatest variation and is the most important of the five; in large amounts, it can mask the effects of the other pigments.

Melanocytes are cells that convert tyrosine, an amino acid, into the black pigment called "melanin." The rate of production is controlled by a hormone called "melanocyte-stimulating hormone (MSH)," which is released by the anterior pituitary gland. About a thousand melanocytes occur on each square millimeter of the body (with the exception of the head and the forearms, which have twice as many). Interestingly, all human races vary greatly in color but tend to have the same number of melanocytes, which inherit different abilities to make melanin.

When humans are compared, an uninterrupted array of shades of skin color is found. Traits that show such continuous variation are thought to be controlled by several sets of genes (polygenetic inheritance). Thus, several sets of genes were believed to control the amount of pigmentation. In 2005, researchers at Pennsylvania State University found two variant expressions of a single gene that may be responsible for the observed distribution of human skin color.

Melanocytes convert tyrosine into
melanin by several chemical steps that involve the key enzyme tyrosinase. A functional tyrosinase molecule consists of different amino acids (the building blocks of proteins) and copper. Traces of copper are in the normal human diet and provide the amounts needed for the enzymes.

Tyrosine, the molecule that is converted to melanin, is one of twenty amino acids occurring in biological systems that chain together in various ways to make up different proteins. Eight of these amino acids are essential—that is, they must be present in the diet. The remaining twelve amino acids can be made by chemical modification of the others. Tyrosine is not an essential amino acid. Ample amounts of tyrosine occur in all meats and in most dairy products. If it is not taken into the body in sufficient amounts, however, it will be made from other amino acids. Either way, tyrosine is delivered to the melanocytes and changed into melanin. This product, with its high molecular weight, functions to protect the skin from excessive ultraviolet (UV) radiation.

UV radiation is an invisible part of the sun’s radiation having wavelengths from one hundred to four hundred nanometers. Humans can see the colors of the spectrum from red through violet. Wavelengths of radiation that are slightly longer than red (infrared) cannot be seen but are detected by the body as heat. Wavelengths that are shorter than violet, such as UV, cannot be seen or felt. Nevertheless, UV radiation penetrates the body. In moderation, UV light is valuable for humans because the body uses its energy to synthesize vitamin D. Vitamin D allows the intestinal absorption of calcium to be used for skeletal growth and for nerve and muscle function.

UV radiation poses several risks. A sunburn involves UV radiation damage to epidermal skin cells, which release chemicals that dilate blood vessels, causing redness. Swelling and blistering may occur. When large numbers of cells are destroyed, the skin speeds up production of new cells, which forces the burned cells to peel off. UV radiation also can change the skin’s collagen, a protein that holds tissues together in much the same way that concrete is reinforced by steel rods. The changes in the collagen, possibly by causing cross-linkage between fibers, can permanently wrinkle the skin. Finally, many researchers agree that UV light may also inhibit the immune response by damaging Langerhans cells in the epidermis. When damaged, these large cells lose their ability to alert the other cells of the immune system to infection. The most serious danger is that UV radiation may alter the genetic code within cells, causing cancer.

Melanin protects the cells of the body by blocking and absorbing UV light. People who have more melanin by heredity are not at as high a risk as those who are lighter. (This is not to say that dark-skinned people should not protect themselves from the sun.) In all cases, exposure to UV radiation immediately causes the skin to darken by causing oxygen to combine with the melanin that is already present. Exposure also increases the rate of melanin production and speeds its distribution to other cells, producing more darkening.

Melanocytes are found at the bottom of the outer layer of the skin, which is called the "epidermis." They are also at the base of the shafts of hairs and in the eye, producing coloration of the iris and in the black membrane of the eye behind the retina. The pigment-producing melanocytes in the skin are found at the base of the epidermis among cube-shaped skin cells that cannot make pigment. About thirty-six of these epidermal cells occur for each melanocyte. Melanocytes have long extensions that reach out to protect the regular skin cells. Furthermore, melanin can also be transferred to epidermal cells. Skin color is also influenced by the distribution and size of the pigment granules in the melanocytes. Very dark skin tends to have single, large granules. Lighter skin tends to have clusters of two to four smaller granules.

On a larger scale, small uneven clusters of pigment are called "freckles." These spots of melanin show mostly in lighter-skinned people, are controlled by heredity, and appear with sun exposure to the skin. Because of this uneven distribution of melanin, other cells among the freckles are not protected and can easily be sunburned.

Moles (nevi) are larger, dark spots of melanin that tend to increase as a person ages. Two types occur: the pigment can be deposited into the dermis (intradermal nevi) or can be found between the dermis and the epidermis (junctional nevi). The first type of mole tends to be elevated and have hair growing from it. The second tends to be flat and very dark.

Large amounts of melanin in
hair will cause it to be black. Lesser amounts make it brown, and still less causes it to be blond. White or gray hair has no melanin. Yet a separate gene for a reddish, iron-containing pigment can be inherited. If two of these recessive genes are present, then the hair will be red. Depending on the amount of melanin that is also present, such people range from almost purely red hair to a strawberry blond color to a reddish-brown (auburn). Larger amounts of melanin will cover the red pigment completely.

Lack of melanin in the iris of the eye will scatter light and cause the eye to reflect blue. Larger amounts cause the eye color to be darker. The pigment in the iris serves to block radiation that could sunburn the retina. In 1992, investigators at Boston College found that eye sensitivity increases when the amount of melanin is greater.

Melanin breaks down as it moves toward the outer layers of the epidermis, forming a chemical called "melanoid" in the process. Melanoid can be seen as a yellow color in the thick (calloused) skin of the palms of the hands and the soles of feet.

Carotene is a yellow-to-orange pigment that tends to accumulate in the layer of fat under the skin. This pigment is also responsible for the color of carrots, yellow vegetables, and the yellows in autumn leaves. When taken into the body, carotene is stored in the liver and converted into vitamin A, which is used in vision. Females usually store more carotene than males because of their higher percentages of fat. Asian peoples tend to have combinations of low melanin and higher carotene that produce a yellowish skin hue.

Hemoglobin and oxyhemoglobin are pigments that are found inside red blood cells. Hemoglobin is dark red but looks bluish through the skin. If hemoglobin combines with oxygen, it is called "oxyhemoglobin." Oxyhemoglobin is bright red. Skin color from this pigment varies with the amount of blood that is circulated at the surface of the dermis, the relative amounts of hemoglobin and oxyhemoglobin that are present, and the densities of other pigments. Hemoglobin and oxyhemoglobin affect the color of light-skinned people more than of darker people. The skin of lighter people generally looks reddish, with oxygen-poor veins appearing blue.

Rapid change of hair color, from dark pigmented to gray or white, is impossible because of the slow growth rate of hair. Melanin is deposited into the hair shaft at the root. The hairs grow outward at a rate of about thirteen millimeters a month. Hence, a loss of pigment production would take a long time to show. The myth of rapid change may be based on diseases that cause all the pigmented hair to fall out overnight, leaving only white hairs.

Disorders and Diseases

Pigmentation can be abnormal and associated with disease. Excess
adrenocorticotropic hormone (ACTH) can increase melanin. ACTH contains several hormones, including MSH. Addison disease involves the overproduction of ACTH. Also, certain injuries such as burns, chemical irritations, or some infections may cause an increase in pigmentation, as can pregnancy. Injuries in which melanocytes are destroyed may result in scar tissue that lacks pigmentation. An excessive intake of carotene can cause light skin to turn orange, a condition called "carotenemia."

Skin cancer
has increased over time. In the late twentieth century, the rate doubled every decade from the 1960s to the 1990s. The
ozone layer, a thin layer of gas molecules consisting of three oxygen atoms, was being depleted by chemicals such as refrigerants that were released into the atmosphere. This layer protects life on the planet from the full shower of
ultraviolet radiation that comes from the sun. In 2013, according to the World Health Organization, some two to three million skin cancers were being diagnosed annually. Any changes in the skin, such as a mole that changes in color or begins to grow, should be shown to a doctor. Although moles and other abnormalities in pigmentation are not usually dangerous, some may develop into melanomas.

Researchers have been trying to discover if it is possible to tan safely. Attempts have been made to develop better creams to block UV radiation. Skin cancer is less common among dark-skinned people; it has been reasoned that if melanin could be put into a skin cream, lighter-skinned people could have more of this natural protection. Unfortunately, many sources of melanin are expensive.

Presently, the best way to avoid skin cancer is to avoid the sunlight, especially when and where the light is most intense—at midday, near the equator, during the summer at other latitudes, at high altitudes, and in highly reflective environments such as sand or snow. Additional protection can be found by using a sunscreen lotion with a high sun-protection factor (SPF) of at least 15. SPF 15 permits fifteen times longer exposure before burning (compared to using no sunscreen), and SPF 30 is thought to protect even the fairest skins. The American Academy of Dermatology recommends using SPF 30 or higher.

Nevertheless, even with frequent applications of sunscreens, people may be putting themselves at risk of melanoma, the most serious skin cancer. Specifically, deoxyribonucleic acid (DNA) absorbs and can be directly damaged by the 280 and 315 nanometer range of UV radiation, and it was formerly assumed that this range, called UVB, was the only one about which people had to worry. Sunscreens were initially developed to block only UVB, the “burning rays.” Data collected by Richard B. Setlow and his colleagues at Brookhaven National Laboratory in 1993, however, indicated that longer wavelengths, including some visible light and UVA (315–400 nanometers), can also damage DNA. Setlow suggested that melanin itself absorbs this energy, setting off chemical reactions that produce chemicals that then damage the melanocytes. This process may be the cause of melanoma. The current consensus is that people should protect themselves from all sunlight, using a broad-spectrum sunscreen lotion that protects against both UVA and UVB. The same risks apply to tanning salons.

Most melanomas are skin cancers. They can also be found inside the eye, as a black spot on the white of the eye, on the iris, or in the center of the field of vision. Treatment of such growths with radiation or surgical removal of the tumor are options. Removal of the entire eye may be necessary. Preventive measures include sunglasses that filter UV light. According to the American Academy of Ophthalmology, sunglasses should block 99 to 100 percent of UV radiation. Most manufacturers label their sunglasses.

In 1991, a controlled study was done in which injections of synthetic MSH were tested. The goal was to help prevent sunburn and skin cancer in high-risk individuals who tan poorly. Those receiving MSH showed significant tanning compared to those who received injections of a placebo. Some mild side effects occurred in the MSH group, including some brief flushing and vague stomach discomfort after the injection.

There are several irregularities of pigmentation. If the tyrosinase enzyme is missing, a person will produce no melanin. This condition is inherited among all races, and such a person is called an "albino" (Greek for “white”). Actually, the lack of melanin allows hemoglobin to determine the skin color. In some types of albinism, an affected individual produces reduced amounts of melanin, resulting in an appearance that is only slightly lighter than that found in the individual's family and ethnic community. All albinos have less protection from the sun and, in addition to the risks to the skin, have poor vision because of light reflections off the back of the eye that normally would be absorbed by pigment. With no pigment in the iris, they are also more likely to suffer damage to their retinal cells, resulting in blindness.

Especially in lighter-skinned people, a lack of hemoglobin (anemia) will cause paleness. If a person’s body circulates more blood into the dermis, the skin will appear more reddish or flushed. This could signal that the body is attempting to cool itself or that a person is embarrassed. If the body is cold or emotionally shocked, it may reduce circulation of blood to the surface of the dermis and the individual will appear pale. Lack of normal sunlight can cause a person to slow the production of melanin. A person who is exercising by swimming in cold water may not circulate blood as quickly as it is needed, and the increase of hemoglobin may turn that person blue, a tone that is noticeable in people with both large and small amounts of melanin.

Perspective and Prospects

Scientists believe that the first humans probably had their origin in Africa and were darkly pigmented. As people migrated to the higher latitudes, where the radiation from the sun was less direct, having less pigment may have been adaptive. Less melanin would allow these people to synthesize needed vitamin D where there was less direct sunlight and less UV light. Before individuals began to migrate over long distances, populations were neatly distributed with darker skins near the equator and lighter skins in northern Europe. Inuits are an interesting exception: they have dark skin and live in a northern latitude. Their diet, however, has traditionally included fish livers with sufficient vitamin D.

The possibility of danger from the sun and other radiation is only a recent discovery. Ultraviolet radiation was discovered in 1801. By 1927, H. J. Muller showed in the laboratory that x-rays cause changes in the genetic code of fruit flies that can be inherited. Such changes, called "mutations," can be harmful. Further investigations showed that UV light, while not as dangerous as x-rays, can also cause mutations. The likelihood of mutation in an organism is proportional to the dose of radiation that is received; spacing out the exposure makes no difference.

Attempts to classify races by description of skin color have given little return. Paul Broca (1824–80) developed an elaborate table of twenty colors for cross-matching with the eyes and twenty-four colors for cross-matching with the skin. The color of the skin, however, is extremely difficult to judge: the color itself changes with environmental and physiological conditions, the ability of observers varies, and the lighting conditions under which comparisons are made can make a difference in the results.

To avoid some of these problems, studies have been performed with a device that measures the reflection of various wavelengths by the skin. In 1992, a study of members of the Jirel population in Nepal showed that the reflections from measurements of upper arm skin using three different wavelengths varied as if the reflective properties were controlled by only a single set of genes. Evidently, the use of various wavelengths gives little additional information about color differences.

Bibliography

A.D.A.M. Medical Encyclopedia. "Skin - Abnormally Dark or Light." MedlinePlus, May 13, 2011.

"Albinism." Mayo Foundation for Medical Education and Research, April 2, 2011.

Balter, Michael. "Zebrafish Researchers Hook Gene for Human Skin Color." Science 310, no. 5755 (December 16, 2005): 1754–55.

Freinkel, Ruth K., and David T. Woodley, eds. Biology of the Skin. New York: Parthenon, 2001.

Greeley, Alexandra. “Dodging the Rays.” FDA Consumer 27 (July/August, 1993): 30–33.

Greener, Mark. “Gene for Red Hair Could Shed Light on Skin Pigmentation.” Dermatology Times 20, no. 12 (December, 1999): 19.

Guttman, Cheryl. “Pigmentation Disorders Common in Asians.” Dermatology Times 20, no. 8 (August, 1999): 24.

"Health Effects of UV Radiation." World Health Organization, 2013.

Levine, Norman, ed. Pigmentation and Pigmentary Disorders. Boca Raton, Fla.: CRC Press, 1993.

Schalock, Peter C., ed. "Overview of Skin Pigment." Merck Manual of Home Health Handbook, January, 2013.

Turkington, Carol, and Jeffrey S. Dover. The Encyclopedia of Skin and Skin Disorders. 3d ed. New York: Facts On File, 2007.

"UV Radiation." United States Environmental Protection Agency, June, 2010.

Weedon, David. Skin Pathology. 3d ed. New York: Churchill Livingstone/Elsevier, 2010.

How is the theme of happiness depicted in the novel Fahrenheit 451?

In Fahrenheit 451 the concept of happiness is an elusive one since the society has been desensitized to any genuine emotion.

There is little family interaction that can produce true emotion. 

People whiz through their shallow lives just as they drive at high speeds, experiencing no genuine feeling. During his visit to Montag, Beatty tells him, 

"Life becomes one big pratfall, Montag; everything bang, boff, and wow!" 

This disconnect is what Clarisse questions when she...

In Fahrenheit 451 the concept of happiness is an elusive one since the society has been desensitized to any genuine emotion.

There is little family interaction that can produce true emotion. 

People whiz through their shallow lives just as they drive at high speeds, experiencing no genuine feeling. During his visit to Montag, Beatty tells him, 

"Life becomes one big pratfall, Montag; everything bang, boff, and wow!" 

This disconnect is what Clarisse questions when she converses with Montag in the exposition of the novel. She laughs when he asks her what she and her family talk about, because it is so unnatural to her that he would not know what to say to his own family members. Then, she turns to him and pointedly asks, "Are you happy?" Montag's reaction is very telling: "Am I what?"

Clearly, Montag does not know the meaning of the word, but he has enough depth in himself that he begins to wonder about what Clarisse has said.

He was not happy.... He wore his happiness like a mask and the girl had run off across the lawn with the mask and there was no way of going...to ask for it back.

When he returns home and finds his wife nearly dead, Montag begins to seriously question his existential state the next day. He wonders what is in books that a woman would be willing to die for them. Perhaps there is some emotional contentment that comes from reading, he thinks. It is then that Montag looks at the books he kept from the fire, books which are the record of true human experience. This genuine experience is one that Montag then searches for as he contacts Faber and later becomes a part of the community that knows the meaning of happiness.

What are miscegenation and antimiscegenation laws?

What Is Race?

Implicit in most biological definitions of race is the concept of shared physical characteristics that have come from a common ancestor. Humans have long recognized and attempted to classify and categorize different kinds of people. The father of systematics, Carolus Linnaeus, described, in his system of binomial nomenclature, four races of humans: Africans (black), Asians (dark), Europeans (white), and Native Americans (red). Skin color in humans has been, without doubt, the primary feature used to classify people, although there is no single trait that can be used to do this. Skin color is used because it makes it very easy to tell groups of people apart. However, there are thousands of human traits. What distinguishes races are differences in gene frequencies for a variety of traits. The great majority of genetic traits are found in similar frequencies in people of different skin color. There may not be a single genetic trait that is always associated with people of one skin color while not appearing at all in people of another skin color. It is possible for a person to differ more from another person of the same skin color than from a person of a different skin color.

Many scientists think that the word “race” is not useful in human biology research. Scientific and social organizations, including the American Association of Physical Anthropologists and the American Anthropological Association, have deemed that racial classifications are limited in their scope and utility and do not reflect the evolving concepts of human variability. It is of interest to note that subjects are frequently asked to identify their race in studies and surveys.

It is useful to point out the distinction between an “ethnic group” and a race. An ethnic group is a group of people who share a common social ancestry. Cultural practices may lead to a group’s genetic isolation from other groups with a different cultural identity. Since members of different ethnicities may tend to marry only within their group, certain genetic traits may occur at different frequencies in the group than they do in other ethnic or racial groups, or the population at large.

Miscegenation

Sir Francis Galton, a cousin of Charles Darwin, is often regarded as the father of eugenics. He asserted that humans could be selectively bred for favorable traits. In his 1869 book Hereditary Genius, he set out to prove that favorable traits were inborn in people and concluded that
". . . the average intellectual standard of the Negro race is some two grades below our own. That the average ability of the [ancient] Athenian race is, on the lowest possible estimate, very nearly two grades higher than our own—that is, about as much as our race is above that of the African Negro."

While easily debunked by today's science, the work of Galton was widely accepted by political and scientific leaders of his time. Bertrand Russell even suggested that the United Kingdom should issue color-coded “procreation tickets” issued to individuals based on their status in society: “Those who dared breed with holders of a different colored ticket would face a heavy fine.” These “scientific” findings, combined with social and racial stereotypes, led to the eugenics movement and its development in many countries, including England, France, Germany, Sweden, Canada, and the United States.

Laws were passed to restrict the immigration of certain ethnic groups into the United States. Between 1907 and 1940, laws allowing forcible sterilization were passed in more than thirty states. Statutes prohibiting and punishing interracial marriages were passed in many states and, even as late as 1952, more than half the states still had antimiscegenation laws. The landmark decision against antimiscegenation laws occurred in 1967 when the US Supreme Court declared the Virginia law unconstitutional. The decision,
Loving v. Virginia
, led to the erosion of the legal force of the antimiscegenation laws in the remaining states.

Impact and Applications

In spite of antimiscegenation laws and societal and cultural taboos, interracial matings have been a frequent occurrence. Many countries around the world, including the United States, are now racially heterogeneous societies. Genetic studies indicate that perhaps 20 to 30 percent of the genes in most African Americans are a result of a mixture of white genes from mixed matings since the introduction of slavery to the Americas more than three hundred years ago. Miscegenation has been widespread throughout the world, and there may not even be such a thing as a “pure” race. No adverse biological effects can be attributed to miscegenation.

Key terms




eugenics


:

the control of individual reproductive choices to improve the genetic quality of the human population




hybridization

:

the crossing of two genetically distinct species, races, or types to produce mixed offspring




negative eugenics

:

preventing the reproduction of individuals who have undesirable genetic traits, as defined by those in control




positive eugenics

:

selecting individuals to reproduce who have desirable genetic traits, as seen by those in control




race

:

in the biological sense, a group of people who share certain genetically transmitted physical characteristics





Bibliography

Alonso, Karen. Loving v. Virginia: Interracial Marriage. Berkeley Heights: Enslow, 2000. Print.

Brah, Avtar, and Annie E. Coombes, eds. Hybridity and Its Discontents: Politics, Science, Culture. New York: Routledge, 2000. Print.

Cardon, Lauren S. The White Other in American Intermarriage Stories, 1945–2008. New York: Palgrave, 2012. Print.

Ehlers, Nadine. "Onerous Passions: Colonial Anti-Miscegenaiton Rhetoric and the History of Sexuality." Patterns of Prejudice 45.4 (2011): 319–40. Print..

Kennedy, Randall. Interracial Intimacies: Sex, Marriage, Identity, and Adoption. New York: Pantheon, 2003. Print.

Lubin, Alex. Romance and Rights: The Politics of Interracial Intimacy, 1945–1954. Jackson: UP of Mississippi, 2005. Print.

Moran, Rachel F. Interracial Intimacy: The Regulation of Race and Romance. Chicago: U of Chicago P, 2001. Print.

Robinson, Charles Frank II. Dangerous Liaisons: Sex and Love in the Segregated South. Fayetteville: U of Arkansas P, 2003. Print.

Salesa, Damon Ieremia. Racial Crossings: Race, Intermarriage, and the Victorian British Empire. New York: Oxford UP, 2011. Print.

Sollors, Werner, ed. Interracialism: Black-White Intermarriage in American History, Literature, and Law. New York: Oxford UP, 2000. Print.

Yancey, George. “An Analysis of Resistance to Racial Exogamy.” Journal of Black Studies 31.5 (May 2001): 635. Print.