Zinc: benefits, dosage, contraindications
Other name(s)
Zn
Family or group:
Minerals and trace elements
Indications
Rating methodology
EFSA approval.
Zinc Deficiency ✪✪✪✪✪
Oral or intravenous zinc intake prevents and treats zinc deficiency. However, systematic zinc supplementation is not recommended. Traditionally, zinc supplementation has been used to treat or prevent a deficiency in certain conditions such as anorexia nervosa, malabsorption syndromes, conditions associated with chronic and severe diarrhea, alcoholism and liver cirrhosis, diabetes, AIDS, during recurrent infections, severe burns, after major surgery, during Wilson's disease, or during long-term administration of total parenteral nutrition. Zinc supplementation (136 mg of elemental zinc per day) in patients with cirrhosis and zinc deficiency seems to improve liver function and glucose tolerance, possibly by increasing insulin-like growth factor.
Posologie
Orally
12.7 - 136 mg
Osteoporosis ✪✪✪✪✪
Reduced zinc intake and low serum zinc levels seem to be associated with lower bone mineral density (BMD) in men and women. Some clinical evidence suggests that taking zinc combined with copper, manganese, and calcium might slow bone loss in postmenopausal women. A combination of 1000 mg of calcium per day (as calcium citrate malate) plus a trace element mixture containing 15 mg of zinc (as zinc sulfate), 0.5 mg of copper, and 5 mg of manganese (as gluconate salt) was used over 2 years.
Posologie
Orally
15 mg
2 - years
Zinc Sulfate
Synergies
Acid-Base Balance ✪✪✪✪✪
The EFSA has established that zinc contributes to normal acid-base metabolism.
Posologie
Orally
25 mg
Adults
Oxidative Stress ✪✪✪✪✪
The EFSA has established that zinc can contribute to the protection of cells against free radicals.
Posologie
Oral
25 mg
Adults
Aging Well ✪✪✪✪✪
The EFSA recognizes zinc's contribution to normal DNA synthesis and maintenance of intellectual functions.
Posologie
Oral
25 mg
Adults
Skin Health ✪✪✪✪✪
The EFSA recognizes zinc's contribution to the maintenance of hair, nails, and skin.
Posologie
Oral
25 mg
Adults
Diarrhea ✪✪✪✪✪
Oral zinc intake reduces the duration and severity of acute and persistent diarrhea in malnourished or zinc-deficient children. Oral zinc intake may also reduce mortality associated with diarrhea, especially persistent diarrhea. Elemental zinc (10 to 40 mg per day) was used with an oral rehydration solution for 7 to 15 days to treat diarrhea in children aged 6 months to 5 years suffering from malnutrition or zinc deficiency. In undernourished pregnant women, taking 15 mg of zinc per day from the first or third trimester and for one month postpartum significantly reduces the incidence of diarrhea in infants during the first year of life compared to placebo.
Posologie
Oral
10 - 40 mg
15 - days
Pregnant Women, Children
Wilson's Disease ✪✪✪✪✪
Wilson's disease is characterized by copper accumulation in vital organs, including the liver and brain. Zinc blocks copper absorption and increases the excretion of copper in stools in people with Wilson's disease. Zinc sulfate supplementation, at 220 mg three times a day for 3 months, in patients with Wilson's disease resulted in increased hepatic glutathione and decreased oxidation compared to those using penicillamine.
Posologie
Oral
660 mg
3 - months
Zinc Sulfate
Acne ✪✪✪✪✪
Clinical trials suggest that oral zinc intake, in the form of zinc sulfate or zinc gluconate, may improve acne compared to placebo.
Posologie
Oral
30 - 150 mg
3 - months
zinc acetate, lotion, zinc gluconate, Zinc Sulfate
Anorexia ✪✪✪✪✪
Oral zinc supplements may help increase weight gain and alleviate depressive symptoms in adolescent and adult patients with anorexia nervosa.
Posologie
Oral
14 - 50 mg
Adults, Adolescents
Cold ✪✪✪✪✪
The majority of clinical trials and analyses of clinical research show a significant reduction in the duration of common cold symptoms when adults take lozenges of zinc gluconate or zinc acetate providing 9 to 24 mg of elemental zinc per dose.
Posologie
Oral
9 - 184 mg
Adults
zinc acetate, zinc gluconate
Prophylaxis and treatment of rhinovirus colds with zinc gluconate lozenges.
Zinc gluconate and the common cold: a controlled clinical study.
Two randomized controlled trials of zinc gluconate lozenge therapy of experimentally induced rhinovirus colds.
Warts ✪✪✪✪✪
Preliminary clinical studies suggest that applying a zinc sulfate solution three times a day for 4 weeks improves flat warts, but not common warts, compared to distilled water. Another clinical study suggests that topical application of a zinc oxide ointment twice daily could be equally effective at healing warts as a salicylic acid and lactic acid ointment.
Posologie
Topical
4 - weeks
zinc oxide, Zinc Sulfate
Male Fertility Issues ✪✪✪✪✪
Preliminary clinical research shows that zinc supplementation increases sperm count, testosterone levels, and the incidence of pregnancies in idiopathic sterile men with low testosterone levels.
Posologie
Oral
25 - 66 mg
6 - months
Men
Attention Deficit Disorders ✪✪✪✪✪
Some research suggests that children with attention deficit hyperactivity disorder (ADHD) have lower serum zinc levels than children without ADHD. Other research suggests that patients with ADHD with lower zinc levels may not respond adequately to stimulant treatment. Based on this evidence, zinc presents some interest in improving symptoms in children with ADHD. Oral zinc intake in combination with conventional treatment may slightly improve hyperactivity, impulsivity, and socialization disorders in some children with ADHD. There is evidence that zinc may be more useful in children with high body mass index (BMI), low zinc and low free fatty acid levels. Zinc sulfate has been used at doses of 55 mg (15 mg of elemental zinc) to 150 mg (40 mg of elemental zinc) per day for 6 to 12 weeks.
Posologie
Oral
15 - 40 mg
12 - weeks
Children
Zinc Sulfate
Zinc deficiency in attention-deficit hyperactivity disorder.
Does hair zinc predict amphetamine improvement of ADD/hyperactivity?
Methylphenidate for children and adolescents with autism spectrum disorder.
Double-blind, placebo-controlled study of zinc sulfate in the treatment of attention deficit hyperactivity disorder.
Double-blind, placebo-controlled study of zinc sulfate in the treatment of attention deficit hyperactivity disorder.
AMD ✪✪✪✪✪
Supplementation with antioxidants including vitamins A (15 mg), C (500 mg), E (400 IU), and zinc oxide (80 mg) reduces the risk of vision loss by 27% and slows the progression of the disease.
Posologie
Oral
80 - 500 mg
10 - years
zinc oxide
Synergies
Long-term effects of vitamins C and E, ß-carotene, and zinc on age-related macular degeneration: AREDS report no. 35.
Age-Related Eye Disease Study Research Group. Potential public health impact of age-related eye disease study results: AREDS report no. 11.
Skin Healing ✪✪✪✪✪
For promoting wound healing, topical zinc may improve reepithelialization and collagen synthesis, reduce inflammation, and inhibit bacterial growth.
Posologie
Topical
Herpes ✪✪✪✪✪
Topical zinc application seems to help treat herpes simplex infection. Zinc sulfate appears to reduce the severity and duration of orolabial and genital herpes symptoms.
Posologie
Topical
Zinc Sulfate
Topical treatment of recurrent herpes simplex and post-herpetic erythema multiforme with low concentrations of zinc sulphate solution
A randomized clinical trial on the treatment of oral herpes with topical zinc oxide/glycine
Use of topical zinc to prevent recurrent herpes simplex infection: review of literature and suggested protocols
Type 2 Diabetes ✪✪✪✪✪
Oral zinc might slightly improve glycemic control in some patients. Although animal studies have shown improvement in glycemic control with zinc, human study results are less consistent. A meta-analysis of 12 clinical studies in diabetic patients shows that zinc supplementation reduces fasting blood glucose and glycated hemoglobin (HbA1c) compared to the control group. The reduction in blood glucose seems to be more significant with inorganic zinc, at doses of at least 30 mg per day for at least one month.
Posologie
Orally
50 mg
zinc acetate
Zinc supplementation improves glycemic control for diabetes prevention and management: a systematic review and meta-analysis of randomized controlled trials
The influence of zinc supplementation on the pancreas of streptozotocin-diabetic rats
Diabetes, metallothionein, and zinc interactions: a review
Depression ✪✪✪✪✪
Some preliminary clinical studies have shown that taking zinc at 25 mg per day for 12 weeks, in addition to antidepressant treatment, improves depression scores in patients with major depression. However, zinc may not be beneficial for all patients diagnosed with major depression. This would depend on the subject’s resistance to antidepressant treatments.
Posologie
Orally
25 mg
12 - weeks
Leg Ulcer ✪✪✪✪✪
Clinical research suggests that applying a zinc-hyaluronate gel once a day can improve healing times of ulcers compared to conventional treatment in type 2 diabetic patients with foot ulcers. According to another randomized, double-blind, placebo-controlled study, applying a zinc oxide bandage for 8 weeks on individuals with leg ulcers allowed 83% of treated individuals to heal, compared to 42% healing for those treated with placebo.
Posologie
Topically
220 mg
8 - weeks
zinc oxide
Properties
Essential
The total quantity of zinc is estimated at 2 g in the body. It is a cofactor in many biological processes, including DNA, RNA (messenger between DNA and proteins), and protein synthesis. It is assumed that many proteins that play a role in regulating gene expression contain zinc. European health authorities (EFSA, European Food Safety Authority and the European Commission) have determined that products containing zinc contribute to normal DNA synthesis, normal acid-base metabolism, normal metabolism of foods, carbohydrates (sugars), fatty acids, vitamin A, normal intellectual functions, normal fertility and reproduction, protein synthesis, maintenance of bones, maintenance of hair, nails, and skin, maintenance of normal testosterone levels in the blood, normal vision, normal immune system function, cell division, protection of cells against free radicals (antioxidant effect), if and only if these products contain at least 1.5 mg of zinc per 100 g, 100 ml or per package if the product contains only one portion.
Usages associés
Antioxidant
Zinc limits damage induced by oxidants through different mechanisms. Indeed, it protects against vitamin E depletion, controls the release of vitamin A, contributes to the structure of the extracellular antioxidant enzyme SOD, limits endogenous production of free radicals, and promotes their trapping.
Healing
To aid healing, topical application of Zinc enhances collagen synthesis, epidermal regeneration, reduces inflammation, and limits bacterial proliferation.
Usages associés
Immuno-modulator
Severe zinc deficiency weakens immune function. Even a mild to moderate zinc deficiency can impair the functions of macrophages and neutrophils and the activity of natural killer cells. The body needs zinc to develop and activate T lymphocytes. Individuals with low levels of zinc have shown a reduced lymphocyte proliferation response to mitogens and other immune response disorders that can be corrected by zinc supplementation. These immune function alterations could explain why zinc deficiency has been associated with increased susceptibility to pneumonia and other infections in children in developing countries and the elderly.
Usages associés
Fertility Effect
Zinc impacts male fertility. For example, low zinc levels are found in seminal plasma in cases of male infertility. Clinical studies suggest that transient zinc deficiency results in decreased serum testosterone concentration, as well as decreased seminal volume. Zinc supplementation improves parameters such as sperm count in infertile men, especially with low testosterone levels.
Usages associés
Neurological
Zinc levels are decreased in people suffering from depression. In the brain, zinc plays a role in the hippocampus in neuron communication. Clinical studies have shown that zinc enhances the action of antidepressants. In Alzheimer's disease, zinc seems to play a protective role thanks to its antioxidant properties, but on the other hand, it seems to contribute to the aggregation of beta-amyloid (a small protein whose aggregation is one of the characteristic signs of Alzheimer's).
Usages associés
Antiviral
Zinc may have effects on the rhinovirus. In vitro, it inhibits its multiplication, but its effects on humans are not clear. Indeed, the rhinovirus (responsible for conditions like the common cold) replicates in nasal mucous membranes. Moreover, the bioavailability of zinc at the level of the nasal mucosa and nasal secretions, when administered orally, varies depending on the formulation used, which can influence zinc's effectiveness in the common cold. Zinc could have effects on other viruses, like the respiratory syncytial virus (RSV) or herpes simplex.
Usages associés
Bone Density
Zinc plays a role in the prevention of osteoporosis because it seems involved in bone mineralization. There is a direct relationship between bone strength and zinc levels in the bones. Also, in people with osteoporosis, zinc elimination is higher due to bone degradation.
Usages associés
Hypoglycemic
Preliminary research suggests that people with type 2 diabetes might have an alteration in zinc metabolism and consequently a zinc deficiency. Studies show that zinc enhances insulin action by increasing glucose transport into cells. Zinc can increase up to 30% the levels of (IGF)-1 (growth factor, it stimulates glucose metabolism, proliferation, and cell differentiation). In a more recent study, in prediabetes stage patients, taking 30 mg of zinc sulfate daily for 6 months improved fasting blood glucose compared to the control group. Zinc supplementation also improved sensitivity and resistance to insulin.
Usages associés
Dermatological Effect
Clinical research suggests that zinc has beneficial effects on the skin when used orally or topically. Indeed, zinc seems to improve acne through anti-inflammatory activity and by reducing cutaneous sebum secretion.
Usages associés
Vision
Zinc plays a key role in maintaining vision. Zinc is present in large quantities in the retina and choroid. A zinc deficiency can thus impair vision. Moreover, zinc interacts with vitamin A and taurine in the retina and serves as an antioxidant in the retina and retinal pigment epithelium (involved in light absorption, and its dysfunction is found in diseases such as AMD). Some studies have shown that zinc could slow certain types of degenerative eye diseases.
Usages associés
Safety dosage
Adult from 18 year(s): 12.7 mg - 25 mg
For adults, zinc intake likely to meet the needs of almost all healthy individuals in a population is provided for four phytate intake levels (PIL): 300 mg/day (7.5 mg/day of zinc), 600 mg/day (9.3 mg/day of zinc), 900 mg/day (11 mg/day of zinc), and 1200 mg/day (12.7 mg/day of zinc).
Infant from 7 to 11 months: 2.9 mg
The zinc intake that meets the needs of almost all healthy individuals in a population is 2.9 mg/day for infants from 7 to 11 months.
Pregnant woman from 18 year(s): 14.3 mg - 25 mg
Child from 1 to 3 year(s): 4.3 mg - 7 mg
For children, the fractional absorption of zinc considered in establishing the PRI (Population Reference Intake) was based on data from mixed diets thought to contain varying amounts of phytate; therefore, no phytate intake adjustment was made.
Child from 4 to 6 year(s): 5.5 mg - 10 mg
For children, the fractional absorption of zinc considered in establishing the PRI (Population Reference Intake) was based on data from mixed diets thought to contain varying amounts of phytate; therefore, no phytate intake adjustment was made.
Child from 7 to 10 year(s): 7.4 mg - 13 mg
For children, the fractional absorption of zinc considered in establishing the PRI (Population Reference Intake) was based on data from mixed diets thought to contain varying amounts of phytate; therefore, no phytate intake adjustment was made.
Child from 11 to 14 year(s): 10.7 mg - 18 mg
For children, the fractional absorption of zinc considered in establishing the PRI (Population Reference Intake) was based on data from mixed diets thought to contain varying amounts of phytate; therefore, no phytate intake adjustment was made.
Child from 15 to 17 year(s): 11.9 mg - 22 mg
For children, the fractional absorption of zinc considered in establishing the PRI (Population Reference Intake) was based on data from mixed diets thought to contain varying amounts of phytate; therefore, no phytate intake adjustment was made.
Nursing woman from 18 year(s): 15.6 mg - 25 mg
Interactions
Médicaments
Diuretics: moderate interaction
Amiloride (a potassium-sparing diuretic) can reduce urinary zinc excretion at doses equal to or above 10 mg/day. This effect helps compensate for zinc losses caused by thiazide diuretics. Other potassium-sparing diuretics (spironolactone, triamterene) do not appear to spare zinc. Thiazide diuretics increase zinc excretion by 50 to 60%. This phenomenon is observed for at least 3 years of treatment. Serum zinc levels decrease but remain within normal limits by compensatory mechanisms. However, prolonged diuretic treatment may decrease tissue zinc.
Antidiabetic: moderate interaction
Clinical evidence has shown that zinc can lower blood glucose. Use with caution if the patient is already on antidiabetics; dosage adjustments may be necessary.
Antiretroviral: moderate interaction
Zinc can reduce serum concentrations of atazanavir (reyataz*), and ritonavir (norvir*), by chelation, preventing their absorption. A single oral dose of zinc sulfate at 125 mg does not alter atazanavir concentrations. Furthermore, in patients treated with atazanavir and ritonavir, combination with 125 mg zinc sulfate for 2 weeks reduces atazanavir plasma concentrations by 22% and ritonavir by 16%. However, atazanavir levels remain high enough to prevent HIV replication. Therefore, this reduction is not clinically significant. On the other hand, pharmaceutical studies have shown that zinc reduces the blood level and effect of integrase inhibitors. Integrase inhibitors include: dolutegravir (tivicay*), elvitegravir (vitekta*), and raltegravir (isentress*).
Cephalexin: strong interaction
Zinc decreases the level of cephalexin by chelation, thus preventing its absorption. A pharmacokinetic study showed that taking 250 mg zinc sulfate concurrently with cephalexin at 500 mg decreases the maximum cephalexin concentration by 31%. However, taking the same dose of zinc sulfate 3 hours before taking cephalexin reduces the latter's maximum concentration by 11%. This effect does not exist if zinc is taken 3 hours after the cephalexin.
Cisplatin: moderate interaction
Some studies suggest that zinc stimulates the production of metallothionein (a protein characterized by a high affinity for metal ions) by tumor cells. This protein can inactivate cisplatin, but it is unclear whether zinc supplementation or a zinc-rich diet can cause a clinically significant interference with cisplatin. Moreover, cisplatin may increase zinc excretion.
Captopril: weak interaction
Some data suggest that Captopril increases zinc urinary excretion by chelation through sulfhydryl groups. This excretion appears dose-dependent and treatment duration with Captopril. Increased losses seem more likely with high doses of Captopril (greater than 150 mg/day) taken for several weeks. However, zinc supplementation is not necessary with Captopril. Zinc loss is unlikely with other angiotensin-converting enzyme inhibitors such as enalapril.
Corticosteroid: weak interaction
The hypothalamic-pituitary-adrenal axis is thought to play a role in controlling serum zinc levels. Thus, disruption of this axis by high doses of corticosteroids (>=50mg of prednisone) or longer-term treatment with lower doses may decrease serum zinc levels. Systematic zinc supplementation is not necessary with corticosteroid therapy.
Iron chelator: moderate interaction
* Deferoxamine: It increases zinc urinary excretion. This effect is dose-dependent. However, symptomatic zinc deficiency due to deferoxamine remains rare. Zinc supplementation is necessary for some patients. * Dexrazoxane: Some studies indicate it increases zinc urinary excretion by 10 times, but clinical data remain insufficient. *EDTA (ethylenediaminetetraacetic acid): It is a metal ion chelator, including zinc. EDTA used in lead poisoning treatment can increase zinc urinary excretion by 10 to 17 times and reduce serum levels by 40%. Levels normalize after stopping treatment. Zinc supplementation is necessary in some cases, although there is concern it may reduce EDTA effectiveness.
Penicillamine: moderate interaction
Penicillamine (a copper chelator) can also complex with zinc. It can increase zinc urinary excretion but can also increase intestinal absorption of zinc. Only one case of severe zinc deficiency has been observed. If zinc supplementation is necessary, intake should be spaced 1 to 2 hours apart from penicillamine intake.
Quinolone: moderate interaction
Quinolones form complexes with zinc in the gastrointestinal tract if taken simultaneously, which reduces their absorption. It is advised to take quinolones 2 hours before or 4 to 6 hours after zinc supplementation. Quinolones include ciprofloxacin (cipro*), gemifloxacin (factive*), levofloxacin (levaquin*), moxifloxacin (avelox*).
Tetracycline: moderate interaction
Tetracyclines (achromycin*, sumycin*, declomycin*) form complexes with zinc in the gastrointestinal tract if taken simultaneously, which reduces their absorption. Indeed, the absorption of tetracycline is reduced by 30 to 40% if taken at the same time as 200 mg of zinc sulfate. Moreover, the interaction of zinc with doxycycline (vibramycin*) is not significant. It is advised to take tetracyclines 2 hours before or 4 to 6 hours after zinc supplementation.
Plantes ou autres actifs
Zinc: weak interaction
Calcium supplementation can decrease zinc absorption from food, but there is no significant clinical effect on zinc balance. However, this interaction can be avoided by taking calcium away from meals.
Zinc: weak interaction
Large quantities of zinc can reduce copper absorption. Copper deficiency has been observed in subjects taking 150 mg/day or more of zinc for 2 years.
Zinc: weak interaction
If zinc is taken on an empty stomach, it interferes with iron absorption and vice versa, due to competition phenomena when binding to transport proteins. When taken with meals, these ions complex with food components and no longer compete. Therefore, there is no significant interaction between iron and zinc when taken during meals.
Zinc: weak interaction
Clinical data suggest that zinc supplementation can increase plasma retinol levels (one of the three available forms of vitamin A). A significant increase has been observed at doses up to 30 mg/day for 6 months.
Precautions
Type 2 Diabetes: use with caution
Taking high doses of zinc can decrease blood sugar levels in diabetic patients. Use cautiously and with blood sugar monitoring.
Alcoholism: use with caution
Long-term excessive alcohol consumption leads to decreased zinc absorption and increased urinary excretion.
Renal insufficiency: use with caution
Patients undergoing hemodialysis present a zinc deficiency. Zinc supplementation may be necessary.
HIV infection: use with caution
Some evidence has shown a link between high zinc intake and reduced survival time. Other research suggests that fighting zinc deficiency in HIV-infected patients helps maintain normal immune function. Use cautiously.
Malabsorption syndrome: use with caution
These patients present a zinc deficiency due to decreased absorption and increased renal elimination.
Rheumatoid arthritis: use with caution
Zinc absorption is decreased in individuals with rheumatoid arthritis.
