Zinc is an essential trace mineral, which means that it must be obtained from the diet since the body cannot make enough. Next to iron, zinc is the most abundant trace mineral in the body. Stored primarily in muscle, zinc is also found in high concentrations in red and white blood cells, the retina of the eye, bones, skin, kidneys, liver, and pancreas. In men, the prostate gland stores high amounts of zinc.

Zinc plays an important role in the immune system, which may explain why it is helpful in protecting against infections such as colds. Zinc also plays a role in the regulation of appetite, stress level, taste, and smell. It is essential for normal growth and development, and for most aspects of reproduction in both males and females.

Zinc also has some antioxidant properties, which means that it helps protect cells in the body from the potential damage caused by free radicals. Free radicals occur naturally in the body, but environmental toxins (including ultraviolet light, radiation, cigarette smoking, and air pollution) can also increase the number of these damaging particles. Free radicals are believed to contribute to the aging process as well as the development of a number of health problems including heart disease and cancer. Antioxidants such as zinc can neutralize free radicals and may reduce or even help prevent some of the damage they cause.

The typical daily intake of zinc in the Western diet is approximately 10 mg, two-thirds of the recommended dietary allowance (RDA). Low zinc intake is often seen in the elderly, alcoholics, people with anorexia, and individuals on restrictive weight loss diets. Zinc deficiency can also be caused by diseases that interfere with the absorption of nutrients from food, such as irritable bowel disease, Celiac disease, and chronic diarrhea.

Some of the symptoms of zinc deficiency include loss of appetite, poor growth, weight loss, impaired taste or smell, poor wound healing, skin abnormalities (such as acne, atopic dermatitis and psoriasis), hair loss, lack of menstrual period, night blindness, hypogonadism and delayed sexual maturation, white spots on the fingernails and feelings of depression.

Immune Response
People who are zinc deficient tend to be more susceptible to a variety of infections. Zinc supplementation enhances immune system activity and protects against a range of infections including colds and upper respiratory infections (such as bronchitis). Several important studies have revealed that zinc lozenges may reduce the intensity of the symptoms associated with a cold, particularly cough, and the length of time that a cold lingers. Similarly, nasal zinc gel seems to shorten the duration of a cold while zinc nasal spray does not.

Such immune enhancement has been demonstrated in special populations including people with sickle cell anemia and the elderly. Those who have sickle cell anemia are often in and out of the hospital with complications from their condition, including infection. They are also frequently zinc deficient. One small scale but well designed study revealed that use of zinc supplements for three years not only improved immune function in those with sickle cell anemia, but also decreased the number of infections and hospitalizations during that time course.

Similarly, 80 elderly patients living in a nursing home had fewer infections when receiving zinc supplements over a two year period than those who received placebo.

HIV/AIDS
Zinc deficiency is common in people with HIV (even before symptoms appear) or AIDS. In people with AIDS, low levels of zinc may be a result of poor absorption, medications, and/or loss of this important nutrient through vomiting or diarrhea. Zinc deficiency leads to increased susceptibility to infection in people with AIDS (called an opportunistic infection). When studied, zinc supplementation has increased CD4 counts (the marker of the white blood cells that fight infection) and improved weight (weight loss is a serious problem in people with this health problem) in those with HIV. Similarly, people with HIV were less likely to develop an opportunistic infection when taking zinc along with a medication used for HIV known as AZT. If you are HIV positive or have AIDS, speak with your physician about the safety, appropriateness, and dose of zinc.

Burns
It is very important for people who have sustained serious burns to obtain adequate amounts of nutrients in their daily diet. Burn patients in hospitals are often given diets high in calories and protein to speed recovery. When skin is burned, a substantial percentage of micronutrients, such as copper, selenium, and zinc may be lost. This increases the risk for infection, slows the healing process, prolongs the hospital stay, and even increases the risk of death. Although it is unclear which micronutrients are most beneficial for people with burns, many experts suggest that a multivitamin containing zinc and other vital nutrients be included in the therapy to aid recovery.

Diabetes
Zinc levels tend to be low in people with diabetes, particularly type 2 diabetes. Plus, zinc plays an important role in production and storage of insulin. For these reasons, zinc supplements may prove to be helpful for some people with this health problem.

Eating Disorders
Studies have shown that people with anorexia and bulimia are often deficient in zinc. Deficiency in this mineral may reduce the sensation of taste and contribute to a loss of appetite. Zinc supplementation seems to help enhance weight gain, increase body mass index, regulate normal appetite signals, improve self-body image, and diminish the obsession with weight, particularly when combined with psychotherapy and other standard treatment approaches.

Low Fertility in Males
Low levels of zinc can contribute to impaired male fertility. Although studies are somewhat premature at this point, zinc supplements may increase sperm count and improve sperm motility, particularly in smokers.

Attention-Deficit Hyperactive Disorder (ADHD)
Children with ADHD tend to have lower blood zinc levels than children without ADHD. Also, children with even mildly diminished levels of zinc seem to be less likely to improve from a commonly prescribed medication for ADHD than children with normal zinc levels.

Diarrhea
Because of its role in immune system function, deficiencies in zinc make infants susceptible to acute diarrhea. In malnourished children, supplementation can have a protective effect. One study showed that supplementation of pregnant women in an undeveloped country (where malnutrition rates are high) significantly reduced the incidence of diarrhea in their babies. In addition, people suffering from chronic diarrhea are at an increased risk for zinc deficiency and would likely benefit from a multivitamin containing zinc.

Osteoporosis
Zinc is essential for maintaining proper bone health throughout life. Zinc has been shown to stimulate bone formation and inhibit bone loss in animal studies and may prove useful in preventing or treating osteoporosis in people.

Acne
There is some evidence that zinc supplementation (such as zinc gluconate) reduces acne inflammation. Studies to date have had certain limitations, however. Therefore, it is difficult to draw definite conclusions about how much zinc to use, what type of zinc is best, and the duration of treatment.

Antibiotics such as erythromycin and tetracycline are sometimes combined with zinc in topical preparations for inflammatory acne. It is unclear whether the zinc enhances the effects of the antibiotics, or simply serves as a mode of delivery for the antibiotics.

Herpes simplex
Topical preparations of zinc have shown benefit in relieving symptoms and preventing recurrences of oral herpes lesions (canker sores).

Tuberculosis
Diets lacking in certain nutrients, including zinc, may be linked to abnormalities in immune function. This may make certain individual more likely to contract tuberculosis (TB), particularly the elderly, children, alcoholics, the homeless, and HIV-infected individuals.

A recent well-designed study of people with tuberculosis in Indonesia found that zinc (together with vitamin A) may actually enhance the effects of certain TB drugs. These changes were demonstrated just two months after starting the supplements. More research is warranted. Until then, your doctor will determine if the addition of zinc and vitamin A is appropriate and safe.

Age-related Macular Degeneration
Although results of studies have been somewhat mixed, the antioxidant properties of zinc may help prevent this debilitating but very common eye condition or delay its progression. More research is needed.

Premenstrual Syndrome (PMS)
Zinc levels may be low in women with PMS. Zinc is required for synthesis and action of many hormones, including sex hormones. This change to sex hormones may explain the possible connection between zinc and PMS. However, it is not currently known whether zinc supplements or increased zinc in the diet will lessen the symptoms of PMS.

Cervical Dysplasia
High levels of zinc in the blood may correspond to an improved chance for the changes in the cervix seen with cervical dysplasia (a precancerous condition screened for by pap smear) to revert to normal. How this relates to zinc or vitamin A supplements is not known; more research is needed.

Other
The following is a partial list of health problems that may increase the need for zinc or affect how the body absorbs or uses this mineral. It is not known, however, whether zinc supplementation will aid the treatment of most of these conditions.

• Acrodermatitis enteropathica (a skin disorder that is due to an inherited inability to absorb zinc properly; generally affects the limbs, mouth, or anus and may include hair loss and diarrhea)
• Alcoholism
• Cirrhosis (liver disease)
• Kidney disease
• Celiac disease 
• Inflammatory bowel disease (ulcerative colitis and Crohn's disease)
• High blood pressure 
• Pancreatic conditions 
• Prostate problems (zinc levels tend to be low in men with inflammation of the prostate [prostatitis] and prostate cancer; the relationship between zinc and enlarged prostate [called benign prostatic hyperplasia or BPH] is less clear; some studies of men with BPH have shown low zinc levels while others have shown high levels of this mineral)
• Pregnancy 
• Breast feeding 
• Birth control pills 

The body absorbs 20% to 40% of the zinc present in food. Zinc from animal foods like red meat, fish, and poultry is more readily absorbed by the body than zinc from plant foods. Dietary fiber, particularly phytates, can interfere with the body's ability to absorb zinc. Zinc is best absorbed when taken with a meal that contains protein.

The best sources of zinc are oysters (richest source), red meats, poultry, cheese (ricotta, Swiss, gouda), shrimp, crab, and other shellfish. Other good, though less easily absorbed sources of zinc include legumes (especially lima beans, black-eyed peas, pinto beans, soybeans, peanuts), whole grains, miso, tofu, brewer's yeast, cooked greens, mushrooms, green beans, tahini, and pumpkin and sunflower seeds.

Zinc sulfate is the most frequently used supplement. This is the least expensive form, but it is the least easily absorbed and may cause stomach upset. Health care providers usually prescribe 220 mg zinc sulfate, which contains approximately 55 mg of elemental zinc.

The more easily absorbed forms of zinc are zinc picolinate, zinc citrate, zinc acetate, zinc glycerate, and zinc monomethionine. If zinc sulfate causes stomach irritation, another form, such as zinc citrate, should be tried.

The amount of elemental zinc is listed in milligrams on the product label. Usually this will be between 30 and 50 mg. In determining if there is a need for supplemental zinc, the fact that the average daily intake of zinc from food sources is 10 to 15 mg should be taken into account.

Zinc lozenges, used for treating colds, are available in most drugstores. There are also nasal sprays developed to reduce nasal and sinus congestion, but studies using this method have not been successful. Nasal gels seem to work better than the spray.

Zinc should be taken with water or juice. However, if zinc causes stomach upset, it can be taken with meals. It should not be taken at the same time as iron or calcium supplements.

A strong relationship exits between zinc and copper. Too much of one can cause a deficiency in the other. Long-term use of zinc (including zinc in a multivitamin) should be accompanied by copper. For every 15 mg of zinc, include 1 mg of copper.

If you are considering using zinc supplements, particularly for children, be sure to discuss the safety and dosage with your healthcare provider.

Daily intake of dietary zinc (according to the U.S. RDA) are listed below:

Pediatric

• Infants birth to 6 months: 2 mg (AI)
• Infants 7 to 12 months: 3 mg (RDA)
• Children 1 to 3 years: 3 mg (RDA)
• Children 4 to 8 years: 5 mg (RDA)
• Children 9 to 13 years: 8 mg (RDA)
• Males 14 to 18 years: 11 mg (RDA)
• Females 14 to 18 years: 9 mg (RDA)

Adult

• Males 19 years and older: 11 mg (RDA)
• Females 19 years and older: 8 mg (RDA)
• Pregnant females 14 to 18 years: 13 mg (RDA)
• Pregnant females 19 years and older: 11 mg (RDA)
• Breastfeeding females 14 to 18 years: 14 mg (RDA)
• Breastfeeding females 19 years and older: 12 mg (RDA)

Therapeutic ranges (elemental zinc):

• Men: 30 to 60 mg daily
• Women: 30 to 45 mg daily

Doses over the amounts listed should be limited to only a few months under the supervision of a healthcare professional.

Because of the potential for side effects and interactions with medications, dietary supplements should be taken only under the supervision of a knowledgeable healthcare provider.

Research has shown that less than 50 mg a day is a safe amount to take over time, but researchers are not sure what happens if more is taken over a long period. Taking more than 150 mg per day may interfere with the body's ability to use other minerals.

Common side effects of zinc include stomach upset, nausea, vomiting, and a metallic taste in the mouth. Other reported side effects of zinc toxicity are dizziness, headache, drowsiness, increased sweating, loss of muscle coordination, alcohol intolerance, hallucinations, and anemia.

Unlike the reasonable doses described, very high doses of zinc may actually weaken immune function. High doses of zinc may also lower HDL ("good") cholesterol and raise LDL ("bad") cholesterol. This may be due to a copper deficiency brought on by the long-term use of zinc. To prevent a copper deficiency and avoid a lowering of HDL cholesterol, be sure to supplement both minerals in a ratio of zinc:copper = 2:1.

If you are currently being treated with any of the following medications, you should not use zinc without first talking to your healthcare provider.

Blood Pressure Medications, ACE Inhibitors
A class of medications called ACE Inhibitors, such as captopril and enalpril, used for high blood pressure may deplete zinc stores.

Antibiotics
Zinc may decrease the absorption of oral quinolones, a class of antibiotics that includes ciprofloxacin, norfloxacin, ofloxacin, and levofloxacin, as well as tetracycline antibiotics (including tetracycline, doxycycline, and minocycline).

Hormone Replacement Therapy (HRT)
HRT, consisting of estrogen and progesterone derivatives may reduce loss of zinc in the urine, particularly in women with osteoporosis.

Hydralazine
There has been at least one report of an interaction between zinc and hydralazine, a medication used to treat high blood pressure, which resulted in a lupus-erythematosus-like syndrome (characterized by a facial butterfly rash, fever, leg and mouth ulcers, and abdominal distress).

Immunosuppressant Medications
Since zinc supports immune function, it should not be taken with corticosteroids, cyclosporine, or other medications intended to suppress the immune system.

Nonsteroidal Anti-inflammatory Drugs (NSAIDs)
Zinc interacts with NSAIDs and could reduce the absorption and effectiveness of these medications. Examples of NSAIDs, which help to reduce pain and inflammation, include ibuprofen, naprosyn, piroxicam, and indomethacin.

Penicillamine
This medication, used to treat Wilson's disease (excessive amounts of copper that accumulate in the brain, liver, kidney, and eyes) and rheumatoid arthritis, decreases zinc levels.

Abul HT, Abul AT, Al-Althary EA, Behbehani AE, Khadadah ME, Dashti HM. Interleukin-1 alpha (IL-1 alpha) production by alveolar macrophages in patients with acute lung diseases: the influence of zinc supplementation. Mol Cell Biochem. 1995;146(2):139-145.

Age-Related Eye Disease Study Research Group. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8. Arch Ophthalmol. 2001;119(10):1417-1436.

Altaf W, Perveen S, Rehman KU, et al. Zinc supplementation in oral rehydration solutions: experimental assessment and mechanisms of action. J Am Coll Nutr. 2002;21(1):26-32.

Anderson RA, Roussel AM, Zouari N, Mahjoub S, Matheau JM, Kerkeni A. Potential antioxidant effects of zinc and chromium supplementation in people with type 2 diabetes mellitus. J Am Coll Nutr. 2001;20(3):212-218.

Arnold LE, Pinkham SM, Votolato N. Does zinc moderate essential fatty acid and amphetamine treatment of attention deficit/hyperactivity disorder? J Child Adolesc Psychopharmacol. 2000;10:111-117.

Baumgaertel A. Alternative and controversial treatments for attention-deficit/hyperactivity disorder. Pediatr Clin of North Am. 1999;46(5):977-992.

Bekaroglu M, Aslan Y, Gedik Y. Relationships between serum free fatty acids and zinc, and attention deficit hyperactivity disorder: a research note. J Child Psychol Psychiatry. 1996;37(2):225-227.

Belongia EA, Berg R, Liu K. A randomized trial of zinc nasal spray for the treatment of upper respiratory illness in adults. Am J Med. 2001;111(2):103-108.

Berger MM, Spertini F, Shenkin A, et al. Trace element supplementation modulates pulmonary infection rates after major burns: a doublt-blind, placebo-controlled trial. Am J Clin Nutr. 1998;68(2):365-371.

Birmingham CL, Goldner EM, Bakan R. Controlled trial of zinc supplementation in anorexia nervosa. Int J Eating Disord. 1994;15:251-255.

Brignola C, Belloli C, De Simone G, et al. Zinc supplementation restores plasma concentrations of zinc and thymulin in patients with Crohn's disease. Aliment Pharmacol Ther. 1993;7:275-280.

Brion M, Lambs L, Berthon G. Metal ion-tetracycline interactions in biological fluids. Part 5. Formation of zinc complexes with tetracycline and some of its derivatives and assessment of their biological significance. Agents Actions. 1985;17:230-242.

Brouwers JR. Drug interactions with quinolone antibacterials. Drug Saf. 1992;7(4):268-281.

Cai J, Nelson KC, Wu M, Sternberg P Jr, Jones DP. Oxidative damage and protection of the RPE. Prog Retin Eye Res. 2000;19(2):205-221.

Capocaccia L, Merli M, Piat C, Servi R, Zullo A, Riggio O. Zinc and other trace elements in liver cirrhosis. Ital J Gastoenterol. 1991;23(6):386-391.

Chausmer AB. Zinc, insulin and diabetes. J Am Coll Nutr. 1998;17(2):109-115.

Cho E, Stampfer MJ, Seddon JM, et al. Prospective study of zinc intake and the risk of age-related macular degeneration. Ann Epidemiol. 2001;11(5):328-336.

Chuong CJ, Dawson EB. Zinc and copper levels in premenstrual syndrome. Fertil Steril. 1994;62(2):313-320.

Congdon NG and West KP. Nutrition and the eye. Curr Opin Opthalmol. 1999;10:464-473.

Costello LC, Franklin RB. Novel role of zinc in the regulation of prostate citrate metabolism and its implications in prostate cancer. Prostate. 1998;35(4):285-296.

Das UN. Nutritional factors in the pathobiology of human essential hypertension. Nutrition. 2001;17(4):337-346.

Dendrinou-Samara C, Tsotsou G, Ekateriniadou E, et al. Anti-inflammatory drugs interacting with Zn(II), Cd(II) and Pt(II) metal ions. J Inorg Biochem. 1998; 71: 171-179.

De-Souza DA, Greene LJ. Pharmacological nutrition after burn injury. J Nutr. 1998;128:797-803.

Dreno B, Amblard P, Agache P, Sirot S, Litoux P. Low doses of zinc gluconate for inflammatory acne. Acta Derm Venereol. 1989;69:541-543.

Dreno B, Trossaert M, Boiteau HL, Litoux P. Zinc salts effects on granulocyte zinc concentration and chemotaxis in acne patients. Acta Dermatol Venereol. 1992;72:250-252.

Dutkiewicz S. Zinc and magnesium serum levels in patients with benign prostatic hyperplasia (BPH) before and after prazoxin therapy. Mater Med Pol. 1995;27(1):15-17.

Eby GA. Zinc ion availability—the determinant of efficacy in zinc lozenge treatment of common colds. J Antimicrob Chemother. 1997;40:483–493.

Fortes C, Forastiere F, Agabiti N, et al. The effect of zinc and vitamin A supplementation on immune response in an older population. J Am Geriatr Soc. 1998;46:19–26.

Garland ML, Hagmeyer KO. The role of zinc lozenges in treatment of the common cold. Ann Pharmacother. 1998;32:63–69.

Geerling BJ, Badart-Smook A, Stockbrügger RW, Brummer R-JM. Comprehensive nutritional status in recently diagnosed patients with inflammatory bowel disease compared with population controls. Eur J Clin Nutr. 2000;54:514-521.

Girodon F, Lombard M, Galan P, et al. Effect of micronutrient supplementation on infection in institutionalized elderly subjects: a controlled trial. Ann Nutr Metab. 1997;41(2):98-107.

Godfrey HR, Godfrey NJ, Godfrey JC, Riley D. A randomized clinical trial on the treatment of oral herpes with topical zinc oxide/glycine. Altern Ther Health Med. 2001;7(3):49-56.

Goldenberg RL, Tamura T, Neggers Y, et al. The effect of zinc supplementation on pregnancy outcome [see comments]. JAMA. 1995;274(6):463-468.

Golik A, Zaidenstein R, Dishi V, et al. Effects of captopril and enalapril on zinc metabolism in hypertensive patients. J Am Coll Nutr. 1998;17:75–78.

Grahn BH, Paterson PG, Gottschall-Pass KT, Zhang Z. Zinc and the eye. J Am Coll Nutr. 2001;20(2 Suppl):106-118.

Hambridge M. Human zinc deficiency. J Nutr. 2000;130(5S suppl):1344S- 1349S.

Herzberg M, Lusky A, Blonder J, Frenkel Y. The effect of estrogen replacement therapy on zinc in serum and urine. Obstet Gynecol. 1996;87(6):1035-1040.

Hines Burnham, et al, eds. Drug Facts and Comparisons. St. Louis, MO:Facts and Comparisons; 2000:1295.

Hirt M, Nobel Sion, Barron E. Zinc nasal gel for the treatment of common cold symptoms: A double-blind, placebo-controlled trial. ENT J. 2000;79(10):778-780, 782.

Humphries L, Vivian B, Stuart M, McClain CJ. Zinc deficiency and eating disorders. J Clin Psychiatry. 1989;50(12):456-459.

Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press; 2001. Accessed February 26, 2002 at http://www.iom.edu/

Karyadi E, West CE, Schultnick W, et al. A double blind, placebo-controlled study of vitamin A and zinc supplementation in persons with tuberculosis in Indonesia: effects on clinical response and nutritional status. Am J Clin Nutr. 2002;75:720-727.

Kristal AR, Stanford JL, Cohen JH, Wicklund K, Patterson RE. Vitamin and mineral supplement use is associated with reduced risk of prostate cancer. Can Epidemiol. 1999;8(10):887-892.

Krowchuk DP. Treating acne. A practical guide. Med Clin North Am. 2000;84(4):811-828.

Li RC, Lo KN, Lam JS, et al. Effects of order of magnesium exposure on the postantibiotic effect and bactericidal activity of ciprofloxacin. J Chemother. 1999;11(4):243-247.

Lih-Brody L, Powell Sr, Collier KP, et al. Increased oxidative stress and decreased antioxidant defenses in mucosa of inflammatory bowel disease. Dig Dis Sci. 1996;41(10):2078-2086.

Liu T, Soong SJ, Alvarez RD, Butterworth CE Jr. A longitudinal analysis of human papillomavirus 16 infection, nutritional status, and cervical dysplasia progression. Cancer Epidemiol Biomarkers Prev. 1995;4(4):373-380.

McClain CJ, Stuart M, Vivian B, et al. Zinc status before and after zinc supplementation of eating disorder patients. J Am Col Nutr. 1992;11:694-700.

McMurray DN, Bartow RA, Mintzer CL, Hernandez-Frontera E. Micronutrient status and immune function in tuberculosis. Ann NY Acad Sci. 1990;587:59-69.

Meynadier J. Efficacy and safety study of two zinc gluconate regimens in the treatment of inflammatory acne. Eur J Dermatol. 2000;10:269-273.

Miller LG. Herbal medicinals: selected clinical considerations focusing on known or potential drug-herb interactions [see comments]. Arch Intern Med. 1998;158(20):2200-2211.

Mulder TPJ, Van Der Sluys Veer A, Verspaget HW, et al. Effect of oral zinc supplementation on metallothionein and superoxide dismutase concentrations in patients with inflammatory bowel disease. J Gastroenterol Hepatol. 1994;9:472-477.

Neuvonen PJ. Interactions with the absorption of tetracyclines. Drugs. 1976;11(1):45-54.

Norregaard J, Lykkegaard JJ, Mehlsen J, Danneskiold-Samsoe B. Zinc lozenges reduce the duration of common cold symptoms. Nutr Review. 1997;55(3):82-85.

Osendarp SJ, van Raaij JM, Darmstadt GL, Baqui AH, Hautvast JG, Fuchs GJ. Zinc supplementation during pregnancy and effects on growth and morbidity in low birthweight infants: a randomised placebo controlled trial. Lancet. 2001;357(9262):1080-1085.

Otomo S, Sasajima M, Ohzeki M, Tanaka I. Effects of D-penicillamine on vitamin B6 and metal ions in rats [in Japanese]. Nippon Yagurigaku Zasshi. 1980;76(1):1-13.

Papageorgiou PP, Chu AC. Chloroxylenol and zinc oxide containing cream (Nels cream®) vs. 5% benzoyl peroxide cream in the treatment of acne vulgaris. A double-blind, randomized, controlled trial. Clin Exp Dermatol. 2000;25:16-20.

Patrick L. Nutrients and HIV: part 2—vitamins A and E, zinc, B-vitamins, and magnesium. Alt Med Rev. 2000;5(1):39-51.

Penny ME, Peerson JM, Marin RM, et al. Randomized, community-based trial of the effect of zinc supplementation, with and without other micronutrients, on the duration of persistent childhood diarrhea in Lima, Peru. J Pediatr. 1999;135(2 Pt 1):208-217.

Physicians' Desk Reference. 54th ed. Montvale, NJ: Medical Economics Co., Inc.: 2000:678-683.

Pizzorno JE, Murray MT. Textbook of Natural Medicine. New York, NY: Churchilll Livingstone. 1999:1210; 1274;1383-1384.

Prasad AS. Clinical and biochemical manifestations of zinc deficiency in human subjects. J Am Coll Nutr. 1985;4(1):65-72.

Prasad AS, Beck FW, Kaplan J, et al. Effect of zinc supplementation on incidence of infections and hospital admissions in sickle cell disease (SCD). Am J Hematol. 1999;61(3):194-202.

Prasad AS, Fitzgerald JT, Bao B, Beck FW, Chandrasekar PH. Duration of symptoms and plasma cytokine levels in patients with the common cold treated with zinc acetate. A randomized, double-blind, placebo-controlled trial. Ann Intern Med. 2000;133(4):245-252.

Pronsky Z. Food-Medication Interactions. 9th ed. Pottstown, Pa: Food-Medicine Interactions; 1995.

Russel RM. Vitamin A and zinc metabolism in alcoholism. Am J Clin Nutr. 1980;33(12):2741-2749.

Safai-Kutti S. Oral zinc supplementation in anorexia nervosa. Acta Psychiatr Scand Suppl. 1990;361(82):14-17.

Sazawal S, Black RE, Jalla S, et al. Zinc supplementation reduces the incidence of acute lower respiratory infections in infants and preschool children: a double-blind, controlled trial. Pediatr. 1998;102(part 1):1–5.

Schauss A, Costin C. Zinc as a nutrient in the treatment of eating disorders. Amer J Nat Med. 1997;4(10)8-13.

Seitz HK, Poschl G, Simanowski UA. Alcohol Cancer. Recent Dev Alcohol. 1998;14:67-95.

Shah D, Sachdev HP. Effect of gestational zinc deficiency on pregnancy outcomes: summary of observation studies and zinc supplementation trials. Br J Nutr. 2001;85 Suppl 2:S101-S108.

Shanker AH, Prasad AS. Zinc and immune function: the biological basis of altered resistance to infection. Am J Clin Nutr. 1998;68(2 Suppl):447S-463S.

Shay NF, Manigan HF. Neurobiology of zinc-influenced eating behavior. J Nutr. 2000;130:1493S-1499S.

Sinclair S. Male infertility: nutritional and environmental considerations. Altern Med Rev. 2000;5(1):28-38.

Thomas JA. Diet , mirconutrients, and the prostate gland. Nutr Rev. 1999;57(4):95-103.

Toren P, Eldar S, Sela BA, et al. Zinc deficiency in attention-deficit hyperactivity disorder. Biol Psychiatry. 1996; 40:1308-1310.

Toyoda M, Morohashi M. An overview of topical antibiotics for acne treatment. Dermatology. 1998;196(1):130-134.

VandenLangenberg GM, Mares-Perlman JA, Klein R, Klein BE, Brady WE, Palta M. Associations between antioxidant and zinc intake and the 5-year incidence of early age-related maculopathy in the Beaver Dam Eye Study. Am J Epidemiol. 1998;148(2):204-214.

Walter RM Jr, Uriu-Hare JY, Olin KL, et al. Copper, zinc, manganese, and magnesium status and complications of diabetes mellitus. Diabetes Care. 1991;14(11):1050-1056.

Wong Wy, Thomas CM, Merkus JM, Zielhuis GA, Steegers-Theunissen RP. Male factor subfertility: possible causes and the impact of nutritional factors. Fertil Steril. 2000;73(3):435-442.

Yamaguchi M. Role of zinc in bone formation and bone resorption. J Trace Elem Exp Med. 1998;11:119-135.

Zaichick VYe, Sviridova TV, Zaichick SV. Zinc in the human prostate gland: normal, hyperplastic and cancerous. Int Urol Nephrol. 1997;29(5):565-574.

Zozaya JL. Nutritional factors in high blood pressure. J Hum Hypertens. 2000;14 Suppl 1:S100-S104.