Learn About Zinc

Zinc is an essential mineral of “exceptional biologic and public health importance“. Zinc deficiency affects about two billion people in the developing world and is associated with many diseases. In children it causes growth retardation, delayed sexual maturation, infection susceptibility, and diarrhea, contributing to the death of about 800,000 children worldwide per year. Enzymes with a zinc atom in the reactive center are widespread in biochemistry, such as alcohol dehydrogenase in humans. Consumption of excess zinc can cause ataxia, lethargy and copper deficiency.

Zinc gluconate (also called zincum gluconium) is the zinc salt of gluconic acid. It is an ionic compound consisting of two moles of gluconate for each mole of zinc. Zinc gluconate is a popular form for the delivery of zinc as a dietary supplement.

Gluconic acid is found naturally, and is industrially manufactured by the fermentation of glucose, typically by Aspergillus niger, but also by other fungi, e.g. Penicillium, or by bacteria, e.g. Acetobacter, Pseudomonas and Gluconobacter. In its pure form, it is a white to off-white powder. It can also be manufactured by electrolytic oxidation, although this is a more expensive process. The advantages are a lower microbiological profile, and a more complete reaction, yielding a product with a longer shelf life. 1

Zinc gluconate may interfere with the absorption of antibiotics, so combinations may be unsafe.

Recommended Zinc Intakes

Intake recommendations for zinc and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine of the National Academies (formerly National Academy of Sciences). DRI is the general term for a set of reference values used for planning and assessing nutrient intakes of healthy people. These values, which vary by age and gender, include the following:

  • Recommended Dietary Allowance (RDA): average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals.
  • Adequate Intake (AI): established when evidence is insufficient to develop an RDA and is set at a level assumed to ensure nutritional adequacy.
  • Tolerable Upper Intake Level (UL): maximum daily intake unlikely to cause adverse health effects.

For infants aged 0 to 6 months, the FNB established an AI for zinc that is equivalent to the mean intake of zinc in healthy, breastfed infants.

Recommended Dietary Allowances (RDAs) for Zinc

Age Male Female Pregnancy Lactation
Birth to 6 months >2 mg* 2 mg*
7 months to 3 years 3 mg 3 mg
4 to 8 years 5 mg 5 mg
9 to 13 years 8 mg 8 mg
14 to 18 years 11 mg 9 mg 13 mg 14 mg
19+ years 11 mg 8 mg 11 mg 12 mg

* Adequate Intake (AI)

Sources of Zinc

A wide variety of foods contain zinc. Oysters contain more zinc per serving than any other food, but red meat and poultry provide the majority of zinc in the American diet. Other good food sources include beans, nuts, certain types of seafood (such as crab and lobster), whole grains, fortified breakfast cereals, and dairy products.

Phytates—which are present in whole-grain breads, cereals, legumes, and other foods—bind zinc and inhibit its absorption. Thus, the bioavailability of zinc from grains and plant foods is lower than that from animal foods, although many grain- and plant-based foods are still good sources of zinc.

Zinc Deficiency

Zinc deficiency is characterized by growth retardation, loss of appetite, and impaired immune function. In more severe cases, zinc deficiency causes hair loss, diarrhea, delayed sexual maturation, impotence, hypogonadism in males, and eye and skin lesions. Weight loss, delayed healing of wounds, taste abnormalities, and mental lethargy can also occur. Many of these symptoms are non-specific and often associated with other health conditions; therefore, a medical examination is necessary to ascertain whether a zinc deficiency is present.

Zinc nutritional status is difficult to measure adequately using laboratory tests due to its distribution throughout the body as a component of various proteins and nucleic acids. Plasma or serum zinc levels are the most commonly used indices for evaluating zinc deficiency, but these levels do not necessarily reflect cellular zinc status due to tight homeostatic control mechanisms. Clinical effects of zinc deficiency can be present in the absence of abnormal laboratory indices. Clinicians consider risk factors (such as inadequate caloric intake, alcoholism, and digestive diseases) and symptoms of zinc deficiency (such as impaired growth in infants and children) when determining the need for zinc supplementation.

Groups at Risk of Zinc Inadequacy

In North America, overt zinc deficiency is uncommon. When zinc deficiency does occur, it is usually due to inadequate zinc intake or absorption, increased losses of zinc from the body, or increased requirements for zinc. People at risk of zinc deficiency or inadequacy need to include good sources of zinc in their daily diets. Supplemental zinc might also be appropriate in certain situations.

People with gastrointestinal and other diseases
Gastrointestinal surgery and digestive disorders (such as ulcerative colitis, Crohn’s disease, and short bowel syndrome) can decrease zinc absorption and increase endogenous zinc losses primarily from the gastrointestinal tract and, to a lesser extent, from the kidney. Other diseases associated with zinc deficiency include malabsorption syndrome, chronic liver disease, chronic renal disease, sickle cell disease, diabetes, malignancy, and other chronic illnesses. Chronic diarrhea also leads to excessive loss of zinc.

The bioavailability of zinc from vegetarian diets is lower than from non-vegetarian diets because vegetarians do not eat meat, which is high in bioavailable zinc and may enhance zinc absorption. In addition, vegetarians typically eat high levels of legumes and whole grains, which contain phytates that bind zinc and inhibit its absorption.

Vegetarians sometimes require as much as 50% more of the RDA for zinc than non-vegetarians. In addition, they might benefit from using certain food preparation techniques that reduce the binding of zinc by phytates and increase its bioavailability. Techniques to increase zinc bioavailability include soaking beans, grains, and seeds in water for several hours before cooking them and allowing them to sit after soaking until sprouts form. Vegetarians can also increase their zinc intake by consuming more leavened grain products (such as bread) than unleavened products (such as crackers) because leavening partially breaks down the phytate; thus, the body absorbs more zinc from leavened grains than unleavened grains.

Pregnant and lactating women
Pregnant women, particularly those starting their pregnancy with marginal zinc status, are at increased risk of becoming zinc insufficient due, in part, to high fetal requirements for zinc. Lactation can also deplete maternal zinc stores. For these reasons, the RDA for zinc is higher for pregnant and lactating women than for other women.

Older infants who are exclusively breastfed
Breast milk provides sufficient zinc (2 mg/day) for the first 4–6 months of life but does not provide recommended amounts of zinc for infants aged 7–12 months, who need 3 mg/day. In addition to breast milk, infants aged 7–12 months should consume age-appropriate foods or formula containing zinc. Zinc supplementation has improved the growth rate in some children who demonstrate mild-to-moderate growth failure and who have a zinc deficiency.

People with sickle cell disease
Results from a large cross-sectional survey suggest that 44% of children with sickle cell disease have a low plasma zinc concentration, possibly due to increased nutrient requirements and/or poor nutritional status. Zinc deficiency also affects approximately 60%–70% of adults with sickle cell disease. Zinc supplementation has been shown to improve growth in children with sickle cell disease.

Approximately 30%–50% of alcoholics have low zinc status because ethanol consumption decreases intestinal absorption of zinc and increases urinary zinc excretion. In addition, the variety and amount of food consumed by many alcoholics is limited, leading to inadequate zinc intake.

Zinc and Health Immune function
Severe zinc deficiency depresses immune function, and even mild to moderate degrees of zinc deficiency can impair macrophage and neutrophil functions, natural killer cell activity, and complement activity. The body requires zinc to develop and activate T-lymphocytes. Individuals with low zinc levels have shown reduced lymphocyte proliferation response to mitogens and other adverse alterations in immunity that can be corrected by zinc supplementation. These alterations in immune function might explain why low zinc status has been associated with increased susceptibility to pneumonia and other infections in children in developing countries and the elderly.

Wound healing
Zinc helps maintain the integrity of skin and mucosal membranes. Patients with chronic leg ulcers have abnormal zinc metabolism and low serum zinc levels, and clinicians frequently treat skin ulcers with zinc supplements. The authors of a systematic review concluded that zinc sulfate might be effective for treating leg ulcers in some patients who have low serum zinc levels. However, research has not shown that the general use of zinc sulfate in patients with chronic leg ulcers or arterial or venous ulcers is effective.

Acute diarrhea is associated with high rates of mortality among children in developing countries. Zinc deficiency causes alterations in immune response that probably contribute to increased susceptibility to infections, such as those that cause diarrhea, especially in children.

Studies show that poor, malnourished children in India, Africa, South America, and Southeast Asia experience shorter courses of infectious diarrhea after taking zinc supplements. The children in these studies received 4–40 mg of zinc a day in the form of zinc acetate, zinc gluconate, or zinc sulfate.

In addition, results from a pooled analysis of randomized controlled trials of zinc supplementation in developing countries suggest that zinc helps reduce the duration and severity of diarrhea in zinc-deficient or otherwise malnourished children. Similar findings were reported in a meta-analysis published in 2008 and a 2007 review of zinc supplementation for preventing and treating diarrhea. The effects of zinc supplementation on diarrhea in children with adequate zinc status, such as most children in the United States, are not clear.

The World Health Organization and UNICEF now recommend short-term zinc supplementation (20 mg of zinc per day, or 10 mg for infants under 6 months, for 10–14 days) to treat acute childhood diarrhea. 2

Sources/More Info:
1. Wikipedia
2. National Institutes of Health (nih.gov)
3. MedlinePlus

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Uses for Zinc

Diarrhea (children)
Multiple studies in developing countries found that zinc supplementation in malnourished children with acute diarrhea may reduce the severity and duration of diarrhea, especially in children with low zinc levels.

Gastric ulcers
The healing process of gastric ulcers may be enhanced through treatment with zinc, although further studies will be needed to determine to what extent zinc may be beneficial for patients with this condition. Most studies report no or few adverse effects associated with its use.

Sickle cell anemia (management)
There is strong scientific evidence to suggest that zinc may help manage or reduce symptoms of sickle cell anemia. Most of these studies reported increased height, weight, immune system function, and testosterone levels and decreased numbers of crises and sickled cells following zinc treatment.

Zinc deficiency
Causes: Zinc deficiency is caused by inadequate intake or absorption, increased zinc excretion, or increased bodily need for zinc. Symptoms: Zinc deficiency symptoms include growth retardation, hair loss, diarrhea, delayed sexual maturation, impotence, eye and skin conditions, and loss of appetite. Additional symptoms may include weight loss, delayed wound healing, taste changes, and mental lethargy.Diagnosis: Zinc can be measured in plasma, red blood cells, white blood cells, and hair.

Acne vulgaris
Based on high-quality studies, topical or oral use of zinc seems to be a safe and effective treatment for acne vulgaris; however, some studies report no or negative effects of zinc. Additionally, many studies used combination treatments. Several studies have identified a positive correlation between serum zinc levels and severity of acne, while others did not, and it remains to be determined to what degree internal zinc levels may correlate with the severity of acne.

Attention deficit hyperactivity disorder (ADHD)
Early studies have shown a correlation between low serum free fatty acids and zinc serum levels in children with attention deficit hyperactivity disorder. Additional studies found that zinc supplements reduced hyperactive, impulsive, and impaired socialization symptoms, but did not reduce attention deficiency symptoms. Zinc supplementation may be a more effective treatment for older children with higher body mass index (BMI) scores.

Down’s syndrome
In several studies, zinc supplements seemed to counteract hypothyroidism and slightly reduce the number of infections in children with Down syndrome. However, zinc did not seem to improve depressed immune systems. Additional human research is needed before a firm conclusion can be made.

Fungal infections (scalp)
Evidence from human trials suggests that zinc pyrithione shampoo may be an effective treatment for tinea versicolor fungal infections of the scalp. No side effects were noted. Additional research is needed before a strong recommendation can be made.

Herpes simplex virus
Low-quality studies have been conducted to assess the effects of zinc (topical or taken by mouth) on herpes type I or II. Several of these studies used combination treatments or permitted the continued use of other medications, so the exact role of zinc in those studies is unclear. However, the positive results obtained in most trials suggest that zinc may represent a safe and effective alternative treatment for herpes type I and II and should encourage further research into the topic using well-designed studies.

High cholesterol
Zinc may improve blood cholesterol levels in hemodialysis patients. There is some evidence that zinc may improve cholesterol ratio of HDL “good cholesterol” versus LDL “bad cholesterol,” which would be considered a positive effect. Well-designed clinical trials are needed before a strong recommendation can be made.

Immune function
Zinc appears to be an essential trace element for the immune system, but research on the effect of zinc supplementation on immune function is scant and mostly focuses on patients with specific diseases. Zinc gluconate appears to have beneficial effects on immune cells. There are relatively few studies that examine zinc levels and the effects of zinc supplementation on the health of the elderly population. Further research is needed before a recommendation can be made.

Plaque/ gingivitis
A few studies have reported significant reduction in plaque accumulation following treatment with zinc rinses and dentifrices. Preliminary research suggests that zinc citrate dentifrice may reduce the severity and occurrence of supragingival calculus formation. However, more well-designed studies are needed to confirm such benefits. More research might help to determine zinc’s potential efficacy in other dental applications.

Wilson’s disease
Wilson’s disease is an inherited disorder of copper metabolism characterized by a failure of the liver to excrete copper, which leads to its accumulation in the liver, brain, cornea, and kidney, with resulting chronic degenerative changes. Early research suggests that zinc treatment may be effective in the management of Wilson’s disease. Relatively few cases of adverse effects have been reported, including one case report presenting a fatality; however, it is unclear whether or not the death was caused by zinc. Several studies have been conducted by the same authors, resulting in possible bias. More well-designed trials are needed to confirm these early results.

Alopecia (hair loss)
A few studies that examined the efficacy of zinc in treating alopecia report conflicting results. Additional information is needed before a conclusion can be made.

Anorexia nervosa
Reports of zinc’s effectiveness in treating symptoms of anorexia nervosa observed in young adults are based on small, low-quality studies, but all agree on the beneficial effects of zinc. Well-designed trials with a larger number of participants are needed to confirm these results.

Bad breath
Chewing gum containing zinc or rinsing out the mouth with a solution containing zinc seemed to reduce bad breath (halitosis) in early studies.

Beta-thalassemia (hereditary disorder)
One small study noted that children with beta-thalassemia who took oral zinc supplements for 1-7 years increased in height more than those who did not take zinc. More studies are needed to confirm these findings.

Blood disorders (aceruloplasminemia)
Data from case reports suggest a potential role for zinc supplementation in aceruloplasminemia, a neurodegenerative disease caused by a gene mutation.

In one study, patients with recurrent boils (furunculosis) treated with zinc found their furuncles did not reappear. Well-designed clinical trials are needed to confirm this potential benefit.

Study results of zinc sulfate supplements given to burn victims to increase healing rate yield mixed results. Further research is needed before a recommendation can be made.

Chronic prostatitis (CP)
Early studies suggest that zinc supplements taken with antibiotics may be more effective than antibiotics alone in reducing pain, urinary symptoms, quality of life, and maximum urethra closure pressure for patients with chronic prostatitis. Further research is needed to confirm these results.

Closed head injuries
Early poorly designed studies indicate that zinc supplementation may enhance neurological recovery in patients with closed head injuries. Further research is needed to confirm these results.

Cognitive deficits (children)
Early studies indicate that daily supplementation with zinc may be of limited usefulness for improving cognition in lead-exposed schoolchildren. Further study may be warranted in this area.

Common cold
There are conflicting results regarding the effect of zinc formulations in treating duration and severity of common cold symptoms. Although zinc might be beneficial in the treatment of cold symptoms, more studies are needed to clarify which zinc formulations may be most effective, which rhinoviruses are affected by zinc, and if nasal sprays provide a useful alternative application route for zinc treatment. A recent study found no significant differences between zinc nasal spray and placebo.Negative results may be caused by using doses of zinc that are too low or they may be affected by the presence of compounds like citric or tartaric acid, which may reduce efficacy due to chelating of the zinc ion.

Crohn’s disease
Early studies of zinc supplements in patients with Crohn’s disease have found positive results. Well-designed clinical trials are needed to confirm these results.

Shampoo containing 1% of zinc pyrithione has been shown to reduce dandruff in some people.

Diabetes (type 1 and type 2)
Diabetic patients typically have significantly lower serum zinc levels compared with healthy controls. In early high-quality studies, zinc supplementation for type-2 diabetics may have beneficial effects in elevating serum zinc level and in improving glycemic control that is shown by decreasing HbA1c concentration. Further study is needed before a strong recommendation can be made.

Diabetic neuropathy (nerve damage)
Oral zinc supplementation may improve glycemic control and severity of peripheral neuropathy. Further research is needed before a recommendation can be made.

Diaper rash
Zinc may reduce the incidence of diaper rash and have a preventative effect.

There are conflicting data regarding the correlation of zinc serum levels and eczema. One study noted that zinc might have caused an increase in itching after several weeks of supplementation. Additional information is needed to help clarify these results.

Exercise performance
Zinc may improve exercise performance in athletes with low serum zinc or zinc deficiencies. Additional evidence is needed before a recommendation can be made.

Gilbert’s syndrome
Gilbert’s syndrome is a common, often inherited disorder that affects processing by the liver of the greenish-brown pigments in bile (called bilirubin). The resulting abnormal increase of bilirubin in the bloodstream can lead to yellowing of the skin (jaundice), but the liver itself remains normal. It is more common in men than women and is named after a French gastroenterologist. Zinc sulfate supplementation seemed to decrease serum unconjugated bilirubin levels in a small study. Well-designed clinical trials are needed to confirm these results.

Growth (stunted infants)
Evidence suggests that supplementation with zinc plus iron (but not with zinc alone) may improve linear growth (length) of stunted infants with low hemoglobin.

Hepatic encephalopathy
Hepatic encephalopathy is abnormal brain function caused by passage of toxic substances from the liver to the blood. Early high-quality trials of zinc for this indication have yielded conflicting results.

Hepatitis C viral infection (chronic)
Early studies have shown that zinc in combination with interferon or interferon and ribavirin for hepatitis C viral infection patients did not show significant benefits, except for lower incidence of gastrointestinal side effects in one study. Further study may be warranted in this area. Recent high-quality evidence suggests that supplementation with polaprezinc in patients undergoing treatment with pegylated interferon alpha-2b and ribavirin may decrease damage to the liver cells.

Patients with HIV/AIDS, especially those with low zinc levels, may benefit from zinc supplementation. Some low-quality studies cite reduction in infections, enhanced weight gain, and immune system function, including increased CD4 and CD8 cells. However, other low quality studies conflict with these findings. Further research is needed before a conclusion can be drawn.

Case report data suggest zinc supplementation may improve thyroid hormone levels (particularly T3) among women with hypothyroidism.

Incision wounds
Although zinc is frequently thought to have beneficial effects on incision wound healing, few studies have investigated this use. Further research is needed before a firm recommendation can be made.

Many studies report beneficial results of zinc supplements on infertility, as expressed in improved sperm quality and number, although this effect may depend on the cause of infertility. A minor increase in abnormal spermatozoa in subfertile males taking zinc was noted in one study. Additional information is needed before a firm conclusion can be drawn.

Kidney function
Early studies show potential improvement in uremic patients taking zinc supplements. Further research is needed to confirm these results. Zinc supplementation may be recommended only in the patients with proven zinc deficiency, but for all chronic renal failure patients it is questionable.
Kwashiorkor (malnutrition from inadequate protein intake)
Short-term zinc supplementation may increase weight gain and decrease infections, swelling, diarrhea, anorexia, and skin ulcers in children with extreme malnourishment.

Leg ulcers
There are conflicting findings regarding the potential benefit of zinc for healing leg ulcers. All studies, however, reported no or few adverse effects.

A few studies have examined the efficacy of zinc treatment in leprosy. Studies of zinc taken by mouth report positive results, while one study of topical zinc reports negative results. Further research is needed before a conclusion can be drawn.

Liver cirrhosis
People with alcoholic liver cirrhosis may be deficient in zinc. Preliminary studies suggest that zinc may benefit these patients. Further evidence is needed to confirm these findings.

Lower respiratory infections in children
Results from large clinical trials suggest that supplementation with zinc may reduce the incidence and severity of lower respiratory infections. Some studies suggest these effects to be only apparent in boys and not girls. A trend toward increased respiratory infections in children has been noted in one study. A recent study does not support the use of zinc supplementation in the management of acute lower respiratory infections requiring hospitalization in indigenous children living in remote areas. Due to conflicting results, further research is needed before a conclusion can be drawn. Future studies could examine whether these adult populations have a similar response.

Macular degeneration
Most studies examining the relationship between dietary zinc intake over many years and macular degeneration have not reported positive correlations. However, one large high-quality study, which examined the efficacy of zinc supplements in preventing loss of visual acuity, found that zinc supplements helped prevent the occurrence of age-related macular degeneration. Since study results are conflicting, additional well-designed clinical trials are needed before a recommendation can be made.

Results are contradictory for the effect of zinc on malaria symptoms. Some high-quality studies suggest no effect of zinc supplementation on the severity of malaria. Other studies suggest that zinc supplementation may reduce the number of stays in hospital and death rate due to P . falciparum infection. Further well-designed trials are required to address these discrepancies.

Menstrual cramps
Case report data suggest a possible role for zinc supplementation in menstrual cramps. Additional study is needed to confirm these findings.

Muscle cramps (cirrhosis)
The results of one case series suggest that zinc supplementation may improve muscle cramps in patients with cirrhosis. Further research is needed to confirm these results.

Evidence from high-quality studies found no association between zinc supplementation and mortality among children. Additional study is needed in this area.

In a few studies of varying quality, patients with cutaneous leishmaniasis were injected with zinc sulfate intralesionally. One study found zinc sulfate was better than meglumine antimoniate for the first four weeks, but no statistical differences were observed after six weeks. Zinc may decrease the severity of infection and re-infection of S . mansoni , but does not seem to prevent initial infection. More research should be done in this area to examine how zinc affects the S . mansonilife cycle and whether this data can be extrapolated to other species of Schistosoma . The effects of zinc on the rate of parasitic re-infestation have been examined in children. No significant effect of zinc treatment was found. Recent high-quality study data suggest that supplementation with zinc and vitamin A may favorably alter infection rate and duration among children. Due to conflicting results in this area, more research is needed before zinc can be recommended for the treatment of parasites.

Poisoning (arsenic)
Results from one study show that a combination of spirulina extract plus zinc may be useful for the treatment of chronic arsenic poisoning with melanosis and keratosis. More research is needed to confirm the effects of zinc alone.

According to multiple reviews, there is no evidence to suggest that zinc supplementation offers benefits during pregnancy, although there is a possible reduction in labor complications and pre-term deliveries. However, results from individual studies suggest a possible benefit of zinc supplementation on blood pressure during pregnancy. Further research is needed before a conclusion can be drawn.

There are only a few studies that examine the efficacy of zinc treatment on symptoms of psoriasis, including psoriasis induced arthritis-like symptoms. One trial noted a reduction in pain and joint swelling. Other studies do not support a role for zinc in alleviating the symptoms of psoriasis. Further, well-designed clinical trials are required to clarify these results.

Radiation-induced mucositis
Radiation has the potential side effect of mucositis, which is inflammation of mucous membranes inside of the mouth, nose, and throat. Two trials suggest that zinc may lower the degree of mucositis in patients on radiation. Further research is needed to confirm these results.

Respiratory disease (respiratory papillomatosis)
Evidence from case reports suggests a possible role for zinc supplementation as adjuvant therapy in JORRP. This area warrants further investigation.

Rheumatoid arthritis
Most trials do not show significant improvements in arthritis symptoms following zinc treatment. Interpretation of some data is difficult because patients in the studies were permitted to continue their previous arthritis medication and most studies used a small number of participants. Well-designed clinical trials are needed before a decision can be made.
Skin damage caused by incontinence
Early evidence suggests that topical zinc oxide oil may help manage perianal and buttock skin damage in incontinent patients. Further research is needed to confirm these results.

Zinc sulfate has been studied for the treatment of recurrent aphthous stomatitis (RAS, mouth ulcer). Study results conflict and no clear conclusion can be drawn at this time.

Taste perception (hemodialysis, cancer)
Results from studies investigating the potential role of zinc in treating taste and smell disorders are contradictory. Recently, a large high-quality trial showed no evidence of a benefit of zinc supplementation on taste alterations among patients undergoing radiation therapy for head and neck cancer. Well-designed research is needed to determine if zinc contributes to the treatment of taste and smell disorders.

Studies on the efficacy of zinc in treating tinnitus yield contradictory results based on subjective findings. Further research is necessary before a conclusion can be drawn.

Little research is available on the efficacy of zinc for the treatment of trichomoniasis, a sexually transmitted disease (STD). One very small study suggests that a zinc sulfate douche and the prescription antibiotic metronidazole may effectively treat patients with recalcitrant trichomoniasis. However, more well-designed human studies are necessary before a firm conclusion can be drawn.

Viral warts
Studies have found conflicting results of the effect of zinc on viral warts. Well-conducted studies are needed to clarify these early results.

Celiac disease
In a very small study, oral zinc supplements did not seem to improve the clinical condition of patients with unresponsive celiac syndrome.

Chronic inflammatory rheumatic disease
Early studies found that zinc supplementation did not seem to benefit patients with chronic inflammatory rheumatic disease.

Continuous ambulatory peritoneal dialysis (CAPD)
Zinc supplementation did not improve the nutritional status in patients on CAPD based on one well-designed trial.

Cystic fibrosis
Zinc supplementation does not seem to affect clinical status, growth velocity, or lung function in children with cystic fibrosis.

Inflammatory bowel disease
Early studies have found that zinc supplementation does not seem to improve inflammatory bowel disease.

Pneumonia (children)
Studies have found that zinc supplementation does not seem to lessen the duration of abnormally fast breathing, hypoxia (inadequate oxygen), chest indrawing, inability to feed, lethargy, severe illness, or hospitalization in children.

Sources/More Info:
1. Wikipedia
2. National Institutes of Health (nih.gov)
3. MedlinePlus

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