Zinc: Health Benefits, Deficiency, Food Sources and Side Effects
Zinc is one of the essential trace elements and its supplementation was found to increase semen volume, sperm motility, and sperm quality in men(1).
Let’s see some of the highlights of Zinc!
- Zinc is necessary for the activity of over 300 enzymes that aid in metabolism, digestion, nerve function, and many other processes(2).
- Zinc supplementation was found to significantly increase the semen volume, sperm motility, and the percentage of normal sperm morphology(1).
- This mineral is also fundamental to skin health, DNA synthesis, and protein production(3).
- Zinc supplements significantly reduce the risk of infections and promote an immune response in older adults(4).
- Zinc may relieve oxidative stress and improve immune response by boosting the activity of T-cells and natural killer cells, which help protect your body from infection(4).
But, What is Zinc?
Zinc is considered an essential nutrient, meaning that your body can’t produce or store it. Zinc is needed for the proper growth and maintenance of the human body. It is found in several systems and biological reactions, and it is needed for immune function, wound healing, blood clotting, thyroid function, and much more. Meats, seafood, dairy products, nuts, legumes, and whole grains offer relatively high levels of zinc.
Zinc deficiency is not uncommon worldwide. Symptoms include slowed growth, low insulin levels, loss of appetite, irritability, generalized hair loss, rough and dry skin, slow wound healing, poor sense of taste and smell, diarrhea, and nausea. Moderate zinc deficiency is associated with disorders of the intestine which interfere with food absorption (malabsorption syndromes), alcoholism, chronic kidney failure, and chronic debilitating diseases.
Zinc plays a key role in maintaining vision, and it is present in high concentrations in the eye. Zinc deficiency can alter vision, and severe deficiency can cause changes in the retina (the back of the eye where an image is focused).
Zinc might also have effects against viruses. It appears to lessen symptoms of the rhinovirus (common cold), but researchers can’t yet explain exactly how this works. In addition, there is some evidence that zinc has some antiviral activity against the herpes virus.
Low zinc levels can be associated with male infertility, sickle cell disease, HIV, major depression, and type 2 diabetes, and can be fought by taking a zinc supplement(5).
Health Benefits of Zinc
- May Improve Immune Function(6)
- May Promote Blood Sugar Control(7,8)
- Helps Fight Acne(9,10)
- May Improve Heart Health(7,11)
- Slows Macular Degeneration(12,13)
- May increase the semen volume, sperm motility and quality(14-16)
Symptoms of Zinc Deficiency
Symptoms of severe zinc deficiency include impaired growth and development, delayed sexual maturity, skin rashes, chronic diarrhea, impaired wound healing and behavioral issues(17).
It is estimated that around 2 billion people worldwide are deficient in zinc due to inadequate dietary intake(18).
Since zinc deficiency impairs your immune system – increasing the chances of infection – zinc deficiency is thought to cause over 450,000 deaths in children under 5 every year(19).
Those at risk of zinc deficiency include(20):
- People with gastrointestinal diseases like Crohn’s disease
- Vegetarians and vegans
- Pregnant and breastfeeding women
- Older infants who are exclusively breastfed
- People with sickle cell anemia
- People who are malnourished, including those with anorexia or bulimia
- People with chronic kidney disease
- Those who abuse alcohol
Symptoms of mild zinc deficiency include diarrhea, decreased immunity, thinning hair, decreased appetite, mood disturbances, dry skin, fertility issues, and impaired wound healing(21).
Natural Foods That You Could Take to Increase Zinc in Your Body
Many animal and plant foods are naturally rich in zinc, making it easy for most people to consume adequate amounts(22).
Foods highest in zinc include(21):
- Shellfish: Oysters, crab, mussels, lobster and clams
- Meat: Beef, pork, lamb and bison
- Poultry: Turkey and chicken
- Fish: Flounder, sardines, salmon and sole
- Legumes: Chickpeas, lentils, black beans, kidney beans, etc.
- Nuts and Seeds: Pumpkin seeds, cashews, hemp seeds, etc.
- Dairy Products: Milk, yogurt and cheese
- Whole Grains: Oats, quinoa, brown rice, etc.
- Certain Vegetables: Mushrooms, kale, peas, asparagus and beet greens
Animal products, such as meat and shellfish, contain high amounts of zinc in a form that your body easily absorbs.
Keep in mind that zinc found in plant-based sources like legumes and whole grains is absorbed less efficiently because of other plant compounds that inhibit absorption(23).
Are There Any Side Effects with Zinc?
Zinc is likely safe for most adults when taken by mouth in amounts not larger than 40 mg daily. Routine zinc supplementation is not recommended without the advice of a healthcare professional. In some people, zinc might cause nausea, vomiting, diarrhea, metallic taste, kidney and stomach damage, and other side effects.
Zinc is possibly safe when taken by mouth in doses greater than 40 mg daily, especially when these doses are taken only for a short period of time. There is some concern that taking doses higher than 40 mg daily might decrease how much copper the body absorbs. Decreased copper absorption may cause anemia.
Taking high amounts of zinc is likely unsafe. High doses above the recommended amounts might cause fever, coughing, stomach pain, fatigue, and many other problems. Taking more than 100 mg of supplemental zinc daily or taking supplemental zinc for 10 or more years doubles the risk of developing prostate cancer. There is also concern that taking large amounts of a multivitamin plus a separate zinc supplement increases the chance of dying from prostate cancer. Taking 450 mg or more of zinc daily can cause problems with blood iron. Single doses of 10-30 grams of zinc can be fatal(5).
Does Zinc Interact with Other Drugs?
- Antibiotics (Quinolone antibiotics)
- Antibiotics (Tetracycline antibiotics)
- Cisplatin (Platinol-AQ)
- Amiloride (Midamor)
Dosages of Zinc That Have Been Studied
- General: Recommended Dietary Allowance (RDA) quantities of zinc have been established for boys and men age 14 and older, 12 mg/day; women 19 and older, 8 mg/day; pregnant women 14 to 18, 10-12 mg/day; pregnant women 19 and older, 11 mg/day;
- For zinc deficiency: In people with mild zinc deficiency, recommendations suggest taking two to three times the recommended dietary allowance (RDA) of zinc for 6 months. In people with moderate to severe deficiency, recommendations suggest taking four to five times the RDA for 6 months.
- For diarrhea: To prevent diarrhea in infants, pregnant women have used 15 mg of zinc, with or without 60 mg of iron and 250 mcg of folic acid, starting 10-24 weeks into pregnancy through one month after giving birth.
- For an inherited disorder that causes copper to build up in many organs (Wilson disease): Zinc acetate (Galzin in the U.S.; Wilzin in Europe) is an FDA-approved drug for treating Wilson disease. The recommended dose, which contains 25-50 mg of zinc, is to be taken three to five times daily.
- For acne: 30-150 mg elemental zinc daily has been used.
- For a disorder of zinc deficiency (acrodermatitis enteropathica): Taking 2-3 mg/kg of elemental zinc daily for a lifetime is recommended for treating an inherited disorder that affects zinc uptake.
- For an eye disease that leads to vision loss in older adults (age-related macular degeneration or AMD): A combination of 80 mg of elemental zinc, 2 mg of copper, 500 mg of vitamin C, 400 IU of vitamin E, and 15 mg of beta-carotene taken daily for 5 years has been used in people with advanced age-related vision loss.
- For an eating disorder (anorexia nervosa): 14-50 mg of elemental zinc has been used daily.
- For the common cold: One zinc gluconate or acetate lozenge, providing 4.5-24 mg elemental zinc, dissolved in the mouth every two hours while awake when cold symptoms are present.
- For depression: 25 mg of elemental zinc has been used daily for 12 weeks along with antidepressant medications.
- For type 2 diabetes: 25 mg of zinc gluconate has been taken twice daily for 8 weeks.
- For diabetes in pregnant women: 30 mg of zinc gluconate has been taken daily for 6 weeks.
- For reduced ability to taste (hypogeusia): 140-450 mg of zinc gluconate has been taken in up to three divided doses daily for up to 4 months. Also, 25 mg of elemental zinc taken daily for 6 weeks has been used. A zinc-containing product called polaprezinc (Promac, Zeria Pharmaceutical Co., Ltd) has also been used.
- For a skin infection caused by Leishmania parasites (Leishmania lesions): 2.5-10 mg/kg of zinc sulfate has been taken in three divided doses daily for 45 days.
- For muscle cramps: 220 mg of zinc sulfate has been taken twice daily for 12 weeks.
- For weak and brittle bones (osteoporosis): A combination of 15 mg of zinc combined with 5 mg of manganese, 1000 mg of calcium, and 2.5 mg of copper has been used.
- For stomach ulcers: 300-900 mg of zinc acexamate has been taken in one to three divided doses daily for up to one year. Also, 220 mg of zinc sulfate has been taken three times daily for 3-6 weeks.
- For bed sores (pressure ulcers): A standard hospital diet plus 9 grams of arginine, 500 mg of vitamin C, and 30 mg of zinc has been used daily for 3 weeks.
- For sickle cell disease: 220 mg of zinc sulfate three times daily has been used. Also, 50-75 mg of elemental zinc taken daily in up to two divided doses for 2-3 years has been used.
- For leg sores caused by weak blood circulation (venous leg ulcer): 220 mg of zinc sulfate taken three times daily has been used along with ulcer dressings.
- For warts: 400-600 mg of zinc sulfate daily for 2-3 months (5).
- Zhao J, Dong X, Hu X, Long Z, Wang L, Liu Q, et al. Zinc levels in seminal plasma and their correlation with male infertility: A systematic review and meta-analysis. Sci Rep. 2016 Mar 2;6:22386.
- Zastrow ML, Pecoraro VL. Designing Hydrolytic Zinc Metalloenzymes. Biochemistry. 2014 Feb 18;53(6):957-78.
- Roohani N, Hurrell R, Kelishadi R, Schulin R. Zinc and its importance for human health: An integrative review. J Res Med Sci. 2013 Feb;18(2):144-57.
- Haase H, Rink L. The immune system and the impact of zinc during aging. Immun Ageing. 2009 Jun 12;6:9.
- Prasad AS, Beck FW, Bao B, Fitzgerald JT, Snell DC, Steinberg JD, et al. Zinc supplementation decreases incidence of infections in the elderly: effect of zinc on generation of cytokines and oxidative stress. The American Journal of Clinical Nutrition. 2007 Mar 1;85(3):837-44.
- Jayawardena R, Ranasinghe P, Galappatthy P, Malkanthi R, Constantine G, Katulanda P. Effects of zinc supplementation on diabetes mellitus: a systematic review and meta-analysis. Diabetol Metab Syndr. 2012;4(1):13.
- Cruz KJC, Morais JBS, de Oliveira ARS, Severo JS, Marreiro D do N. The Effect of Zinc Supplementation on Insulin Resistance in Obese Subjects: a Systematic Review. Biol Trace Elem Res. 2017 Apr;176(2):239-43.
- Dreno B, Moyse D, Alirezai M, Amblard P, Auffret N, Beylot C, et al. Multicenter Randomized Comparative Double-Blind Controlled Clinical Trial of the Safety and Efficacy of Zinc Gluconate versus Minocycline Hydrochloride in the Treatment of Inflammatory Acne vulgaris. Dermatology. 2001;203(2):135-40.
- Gupta M, Mahajan VK, Mehta KS, Chauhan PS. Zinc Therapy in Dermatology: A Review. Dermatology Research and Practice. 2014;2014:1-11.
- Kim J. Dietary zinc intake is inversely associated with systolic blood pressure in young obese women. Nutr Res Pract. 2013;7(5):380.
- Smailhodzic D, van Asten F, Blom AM, Mohlin FC, den Hollander AI, van de Ven JPH, et al. Zinc Supplementation Inhibits Complement Activation in Age-Related Macular Degeneration. DeAngelis MM, editor. PLoS ONE. 2014 Nov 13;9(11):e112682.
- Vishwanathan R, Chung M, Johnson EJ. A Systematic Review on Zinc for the Prevention and Treatment of Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci. 2013 Jun 12;54(6):3985.
- Deng C-H, Zheng B, She S-F. [A clinical study of biological zinc for the treatment of male infertility with chronic prostatitis]. Zhonghua Nan Ke Xue. 2005 Feb;11(2):127-9.
- Zhao J, Dong X, Hu X, Long Z, Wang L, Liu Q, et al. Zinc levels in seminal plasma and their correlation with male infertility: A systematic review and meta-analysis. Sci Rep. 2016 Mar;6(1):22386.
- Schisterman EF, Sjaarda LA, Clemons T, Carrell DT, Perkins NJ, Johnstone E, et al. Effect of Folic Acid and Zinc Supplementation in Men on Semen Quality and Live Birth Among Couples Undergoing Infertility Treatment: A Randomized Clinical Trial. JAMA. 2020 Jan 7;323(1):35.
- Nistor N, Ciontu L, Frasinariu O-E, Lupu VV, Ignat A, Streanga V. Acrodermatitis Enteropathica: A Case Report. Medicine. 2016 May;95(20):e3553.
- Jurowski K, Szewczyk B, Nowak G, Piekoszewski W. Biological consequences of zinc deficiency in the pathomechanisms of selected diseases. J Biol Inorg Chem. 2014 Oct;19(7):1069-79.
- Fischer Walker CL, Ezzati M, Black RE. Global and regional child mortality and burden of disease attributable to zinc deficiency. Eur J Clin Nutr. 2009 May;63(5):591-7.
- Kumssa DB, Joy EJM, Ander EL, Watts MJ, Young SD, Walker S, et al. Dietary calcium and zinc deficiency risks are decreasing but remain prevalent. Sci Rep. 2015 Sep;5(1):10974.
- Saper RB, Rash R. Zinc: an essential micronutrient. Am Fam Physician. 2009 May 1;79(9):768-72.
- Gibson RS. A Historical Review of Progress in the Assessment of Dietary Zinc Intake as an Indicator of Population Zinc Status. Advances in Nutrition. 2012 Nov 1;3(6):772-82.
Disclaimer: The information provided on this page is not a substitute for professional medical advice, diagnosis, or treatment. If you have any questions or concerns about your health, please talk to a healthcare provider.
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