Zinc

Zinc is an essential trace mineral, which, next to iron, is the second most abundant trace mineral in the body. Zinc is stored primarily in muscle but is also found in red and white blood cells, the retina of the eye, bones, skin, kidneys, liver, and pancreas. In men, the prostate gland contains more zinc than any other organ.

Recent research has attempted to determine the true value of zinc lozenges in preventing or reducing cold symptoms, with some studies showing good results. You can buy zinc lozenges in any pharmacy now to treat the common cold.

Uses

Zinc supplements can help the body in the following ways.

• Helps prevent cancer
• Prevents and treats colds
• Boosts the activity of immune system
• Speeds healing of wounds
• Treats and may prevent acne
• May prevent macular degeneration (eyesight deterioration that happens as people age)
• Treats some cases of anorexia nervosa (anorexia is a symptom of zinc deficiency, and the teenage population is at higher risk for zinc deficiency due to poor dietary habits)
• Improves male fertility, especially among smokers
• Treats rheumatoid arthritis (may have anti-inflammatory effects)
• Treats Wilson's disease (a disorder of excess copper storage)
• Decreases changes in the sense of taste during cancer treatments
• Heightens sense of taste and smell

Some conditions may affect how your body absorbs zinc, or may increase your need for zinc. If you have one of the following conditions, you may benefit from zinc supplements.

• Acrodermatitis eteropathica (the inherited disease that causes zinc malabsorption)
• Alcoholism
• Diabetes
• Kidney disease
• Celiac disease
• Inflammatory bowel disease, ulcerative colitis
• Chronic diarrhea
• Pancreatic conditions
• Prostate problems (BPH, prostatitis, cancer)

Women who are pregnant or are breast-feeding, and those who take oral contraceptives may also have an increased need for zinc.

Dietary Sources

We absorb 20 to 40 percent of the zinc that is in our food. Zinc from animal foods like red meat, fish, and poultry is the most readily absorbed form. Zinc in vegetables is less available to our bodies, and vegetable fiber itself lessens how much zinc we can absorb and use. Dairy products and eggs contain fair amounts of zinc, but it is less easily absorbed from these sources.

The following foods are the best sources of usable zinc: oysters (richest source), red meats, shrimp, crab, and other shellfish.

Other good, though less easily absorbed sources, include legumes (especially lima beans, black-eyed peas, pinto beans, soybeans, peanuts), whole grains, miso, tofu, brewer's yeast, cooked greens, mushrooms, green beans, and pumpkin seeds.

Other Forms

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. More easily absorbed forms are available: zinc picolinate, zinc citrate, zinc acetate, zinc glycerate, and zinc monomethionine.

These different forms contain different amounts of zinc in the "compound." Always look for the "amount of elemental zinc" listed in milligrams on the label. Usually this will be between 30 and 50 mg of elemental zinc. Remember that you take in about 10 to 15 mg of zinc from food every day. Your health care provider should take this into account when prescribing how much supplemental zinc you should take. Zinc lozenges are also available in most drug stores and grocery stores, and are used for treating colds. Zinc lozenges are also available for the treatment of colds.

How to Take It

Talk to your health care provider or nutritionist before you take zinc supplements. You get the most benefit from zinc supplements if you take them with water or juice (not milk) in between meals, and don't take them at the same time that you take iron or calcium supplements. If this bothers your stomach, you can take the zinc with a meal.

Precautions

Most trace minerals are toxic if you take too much, and this is true of zinc. Symptoms of toxicity are stomach upset and vomiting, usually occurring if 2,000 mg or more has been swallowed. Studies have stated that up to 150 mg is fairly safe, but that much is usually not needed and may interfere with your body's use of other minerals. 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 you take more than that over a long period. Talk with your health care provider before taking zinc or any other supplement.

One known negative side effect of too much zinc is that it lowers HDL (good) cholesterol and raises LDL (bad) cholesterol. Some research has shown that megadoses of zinc lower immune function, but other studies have not confirmed this. If zinc sulfate causes stomach irritation, try another form, such as zinc citrate. Check with your health care provider first. Other reported side effects of zinc toxicity are dizziness, headache, drowsiness, increased sweating, uncoordination of muscles, alcohol intolerance, hallucinations, and anemia.

Possible Interactions

Zinc decreases the absorption of oral quinolones, a class of antibiotics that includes ciprofloxacin, norfloxacin, ofloxacin, and levofloxacin. If you take these medications and are considering zinc supplementation, talk with your health care provider first.

Penicillamine, a medication used for the treatment of Wilson’s disease and rheumatoid arthritis, decreases zinc levels.

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

Supporting Research

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Copyright © 2000 Integrative Medicine Communications

The publisher does not accept any responsibility for the accuracy of the information or the consequences arising from the application, use, or misuse of any of the information contained herein, including any injury and/or damage to any person or property as a matter of product liability, negligence, or otherwise. No warranty, expressed or implied, is made in regard to the contents of this material. No claims or endorsements are made for any drugs or compounds currently marketed or in investigative use. This material is not intended as a guide to self-medication. The reader is advised to discuss the information provided here with a doctor, pharmacist, nurse, or other authorized healthcare practitioner and to check product information (including package inserts) regarding dosage, precautions, warnings, interactions, and contraindications before administering any drug, herb, or supplement discussed herein.