Zinc
Zinc is a trace mineral that is found in virtually every cell in the body and is a component in over 200 enzymes. Enzymes are molecules involved in speeding up the chemical reactions necessary for body functions. Zinc functions in more enzymatic reactions than any other mineral; low zinc levels affect virtually every system of the body. Zinc is also required for proper action of many body hormones, including insulin, growth hormone, and sex hormones.
Adequate zinc levels are absolutely essential to good health. Zinc is especially important to proper immune function, wound healing, sensory functions, sexual function, and skin health.
Although severe zinc deficiency is very rare in developed countries, it is believed that many individuals in the United States have marginal zinc deficiency, especially in the elderly population. The zinc deficiency can be caused by decreased intake and/or utilization. Dietary surveys indicate that average zinc intakes range from only 47 percent to 67 percent of the RDA. Marginal zinc deficiency may be reflected by an increased susceptibility to infection, poor wound healing, a decreased sense of taste or smell, and a number of minor skin disorders including acne, eczema, and psoriasis. Other physical findings that often correlate with low zinc status include decreased ability to see at night or with poor lighting, growth retardation, testicular atrophy, mouth ulcers, a white coating on the tongue, and marked halitosis.
Zinc - Acne
Several double-blind studies have demonstrated that zinc supplementation produces similar results to tetracycline (an antibiotic) in superficial acne and superior results in deeper acne. Although some people in these studies showed dramatic improvement immediately, the majority usually required twelve weeks of supplementation before good results were achieved.
Zinc - Alzheimer's disease
Zinc deficiency is one of the most common nutrient deficiencies in the elderly and has been suggested to be a major factor in the development of Alzheimer's disease. Preliminary studies with zinc supplementation have shown some beneficial effects. In one small study, ten patients with Alzheimer's disease were given 27 mg of zinc (as zinc aspartate) daily. Only two patients failed to show improvement in memory, understanding, communication, and social contact.
Zinc - Common cold
Zinc possesses some direct antiviral activity, including antiviral activity against several viruses that can cause the common cold. The use of zinc supplementation, particularly in the form of a lozenge, appears to be of value during a cold. However, out of eight double-blind studies, four found zinc lozenges to be effective, while the other four reported no difference between zinc and placebo therapy. This inconsistency is thought to be due to an ineffective lozenge formulation in the negative studies. It appears that, in order for zinc to be effective, it must be ionized in saliva. The study showed that sucking on hard candy lozenges containing zinc gluconate and citric acid delivered an insignificant amount of ionized zinc. It was found that, in the presence of citric acid, saliva completely suppressed the ionization of zinc. It appears that in order for a zinc lozenge to be effective it must be free of sorbitol, mannitol, and citric acid.In the positive double-blind studies, zinc-containing lozenges (Cold-Eeze) significantly reduced the average duration of common colds. The lozenges contained 23 mg of elemental zinc, which the patients were instructed to dissolve in their mouths every two waking hours after an initial double dose. In one study, after seven days, 86 percent of the thirty seven zinc-treated subjects were symptom free, compared to 46 percent of the twenty-eight placebo-treated subjects.
There are many forms of zinc to choose from. While most clinical studies have utilized zinc sulfate, several other forms of zinc have been shown to be better absorbed and utilized, including zinc bound to picolinate, acetate, citrate, glycerate, or monomethionine. Although manufacturers may claim superiority for their particular zinc chelate, there is data to support each of these forms as being very well absorbed.
The dosage range for zinc supplementation for general health support and during pregnancy or lactation is 15 to 20 mg. When zinc supplementation is being used to address specific health concerns, the dosage range for men is 30 to 45 mg; for women 20 to 30 mg.For a common cold, use lozenges that supply 15 to 25 mg of elemental zinc and dissolve them in the mouth without chewing every two waking hours after an initial double dose. Continue for up to seven days. Because high doses of zinc can actually impair immune function, a daily intake of greater than 150 mg of zinc for longer than one week cannot be recommended.
Zinc - Immune system enhancement
Zinc is involved in virtually every aspect of immune function. Zinc supplementation can reverse the low immune function characteristic of aging. In one study, the effect of low-dose zinc supplementation (20 mg/day) on nutritional and immune status was assessed in institutionalized elderly subjects. The most telling effect was that zinc supplementation produced a significant restoration of serum thy-mulin, an immune-enhancing hormone produced by the thymus gland that often decreases with age. Nutritional status was improved because both food intake and serum albumin levels were increased with zinc supplementation.
Zinc - Male sexual function
Zinc is critical for male sexual function. It is involved in hormone metabolism, sperm formation, and sperm motility. Zinc deficiency is characterized by, among many other things, decreased testosterone levels and sperm counts. Zinc levels are typically much lower in infertile men with low sperm counts, indicating that a low zinc status may be a contributing factor to the infertility. Several double-blind studies have shown that zinc supplementation can improve sperm counts and motility. It is especially effective in boosting sperm counts in men with low testosterone levels.
Zinc - Macular degeneration
Zinc has been shown to be beneficial in reducing vision loss in the treatment of macular degeneration.
Zinc - Pregnancy outcome
Low zinc levels are linked to premature births, low birth weight, growth retardation, and preeclampsia a serious condition of pregnancy associated with elevations in blood pressure, fluid retention, and loss of protein in the urine. Studies of zinc supplementation in pregnancy have shown that infants born to the zinc-supplemented mothers had greater body weight and head circumference compared to the placebo group. The zinc-supplemented mothers also had fewer complications of pregnancy.
Zinc - Rheumatoid arthritis
Zinc has antioxidant effects as well as functions in the antioxidant enzyme superoxide dismutase (copper-zinc SOD). Zinc levels are typically reduced in patients with rheumatoid arthritis, and several studies of zinc in the treatment of rheumatoid arthritis have demonstrated a slight therapeutic effect. Most of the studies utilized zinc in the form of sul-fate. Better results might have been produced by using a more absorbable form of zinc.
Zinc Side Effects
If taken on an empty stomach (particularly if taking zinc sulfate), zinc supplementation can result in gastrointestinal upset and nausea. Prolonged intake at levels greater than 90 mg per day may lead to anemia, reduced HDL-cholesterol levels, and depressed immune function.
Do not take more than recommended amounts, especially if pregnant or lactating.
Zinc may decrease the absorption of tetracycline (Achromycin, Sumycin) and ciprofloxacin (Cipro). Take any zinc supplement at least two hours before or after taking these antibiotics.
Use of the following drugs increases the loss of zinc from the body or interferes with absorption: aspirin; AZT (azidothymidine); zidovudine (Retrovir); captopril (Capoten); enalapril (Vasotec); estrogens (oral contraceptives and Premarin); penicillamine (Cuprimine); and the thiazide class of diuretics including chlorothiazide (Diuril and others), chlorthalidone (Hygroton and others}, hydrochlorothiazide (Esidrix, HCTZ, HydroDIURIL, Oretic, and others), and metolazone (Mykrox and Zaroxolyn). Supplementation may be required to maintain zinc status in people taking these drugs.
Zinc supplements should be taken separately from high fiber foods for best absorption. High dosages of calcium or iron can adversely affect zinc absorption.
When using zinc-containing lozenges for the relief of a sore throat or common cold. Do not eat or drink citrus fruits or juices 1/2 hour before or after; the citric acid will negate the effect of zinc.
Acute toxicity is quite rare, as the ingestion of amounts large enough to cause toxicity symptoms (2 g per kg body weight) will usually provoke vomiting. Do the following in case of accidental overdose: If the victim is unconscious or having convulsions, call for an ambulance immediately. If you take the victim to an emergency room, be sure to bring the bottle or container with you. If the victim is conscious, call your local poison control center or a health care professional. The poison control center may suggest inducing vomiting with ipecac syrup (available without a prescription at any pharmacy). DO NOT induce vomiting unless specifically instructed to do so.Pregnant/breast-feeding women - Zinc supplementation at recommended levels is considered beneficial during pregnancy and lactation.Children - Suitable for children at one-half the adult dosage. Note: Toddlers and infants can choke on zinc lozenges, and children often cannot avoid chewing them.
Seniors - Zinc requirements may increase with increasing age due to impaired absorption and utilization.