When supplementing any nutrient, it’s important to consider the appropriate amount to take. If intake is too low, then the desired results might not occur. If supplementation is too high, then negative side-effects could occur.

The Recommended Daily Allowance (RDA) suggests a nutrient’s daily average intake. Although the RDA is the amount needed to prevent a deficiency, it’s not necessarily a therapeutic amount. The RDAs are specific to life stage and gender group for healthy individuals.2 

The Tolerable Upper Intake Level (UL) is the highest daily amount of a nutrient that is unlikely to cause an adverse effect. This limit applies when a nutrient is being consumed at higher, therapeutic levels for an extended period of time, such as in cases of deficiency, illness, and research participation.2 

Zinc supplementation plays an important role for individuals who are deficient or who don’t get enough zinc from their diet. Since our bodies cannot make zinc, it is considered an essential mineral – one that must be obtained from food or supplementation. At any given time, our bodies store 2-3 grams of zinc in our bones and muscles. Some of that zinc is depleted each day as it is used in a variety of functions throughout our bodies.2-4

A low level of zinc can be associated with age, eating a vegetarian or vegan diet, compromised immunity, severe burns, and intravenous nutrition. Although severe zinc deficiency is uncommon, a mild deficiency can have a wide range of symptoms due to the use of zinc in so many bodily functions.2 

One consideration when supplementing zinc involves the interaction between zinc and copper, another essential mineral.

The body uses copper in energy production and to support bone, skin, neurological, and cardiovascular health.* Along with zinc, copper is a component of superoxide dismutase, an important antioxidant enzyme utilized by the immune system.* Although copper deficiency is rare, it can result from high levels of zinc intake because of a decreased ability to absorb and use copper from the diet.2,5-13

Therefore, several research studies have investigated the relationship between zinc intake and copper status. In those studies, the amount of zinc and the length of time taken were analyzed. A daily intake of 60 mg of zinc for 10 weeks (well above the UL) was associated with a decrease in copper status.13

In this study, the zinc intake came from 10 mg from the diet and 50 mg from a zinc supplement. Other sources of non-dietary zinc intake, in addition to zinc-specific supplements, include multi-vitamin/mineral supplements, zinc lozenges, and denture paste.

Additional studies indicate copper supplementation along with zinc helps balance absorption of both nutrients.14 Many alternative and integrative practitioners recommend a ratio of 15 mg of zinc to 1 mg of copper – similar to the ratio achieved if you remain within RDA guidelines.

For example, the average recommendation for zinc is 11 mg per day for healthy adults, slightly more or less based on gender and pregnancy or lactation status. For copper, the average recommendations is 1 mg daily for healthy adults.2 If you are taking a zinc picolinate supplement daily, then it may be time to consider the addition of a copper supplement as well. Or you can take a “multi” with an optimal balance of zinc and copper.

References

  1. Gombart A, Pierre A, Maggini S. A review of micronutrients and the immune system – Working in harmony to reduce the risk of infection. Nutrients 2020;12(1).
  2. Food and Nutrition Board, Institute of Medicine. Dietary reference intakes for vitamin A, vitamin K, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. Washington, D.C.: National Academy Press; 2001:442-501.
  3. Lowe N, Medina M, Stammers A, et al. The relationship between zinc intake and serum/plasma zinc concentration in adults: a systematic review and dose-response meta-analysis by the EURRECA Network. Br J Nutr 2012;108(11):1962-1971.
  4. Lowe N, Dykes F, Skinner A, et al. EURRECA-Estimating zinc requirements for deriving dietary reference values. Cit Rev Food Sci Nutr 2013;53(10):1110-1123.
  5. Boukaiba N, Flament C, Acher S, et al. A physiological amount of zinc supplementation: effects on nutritional, lipid, and thymic status in and elderly population. Am J Clin Nutr 1993;57(4):566-572.
  6. Burke D, DeMicco F, Taper L, Ritchey S. Copper and zinc utilization in elderly adults. J Gerontol 1981;36(5):558-563.
  7. Festa M, Anderson H, Dowdy R, Ellersieck M. Effect of zinc intake on copper excretion and retention in men. Am J Clin Nutr 1985;41(2);285-292.
  8. Fischer P, Giroux A, L’Abbe M. Effect of zinc supplementation on copper status in adult men. Am J Clin Nutr 1984;40(4):743-746.
  9. Fosmire G. Zinc toxicity. Am J Clin Nutr 1990;51(2):225-227.
  10. Prasad A, Brewer G, Schoomaker E, Rabbani P. Hypocupremia induced by zinc therapy in adults. JAMA 1978;240(20):2166-2168.
  11. Samman S, Roberts D. The effect of zinc supplements on plasma zinc and copper levels and the reported symptoms in healthy volunteers. Med J Aust 1987;146(5):246-249.
  12. Samman S, Roberts D. The effect of zinc supplements on lipoproteins and copper status. Atherosclerosis 1988;70(3):247-252.
  13. Yadrick M, Kenney W, Winterfeldt E. Iron, copper, and zinc status: response to supplementation with zinc or zinc and iron in adult females. Am J Clin Nutr 1989;49(1):145-150.
  14. August D, Janghorbani M, Young V. Determination of zinc and copper absorption at three dietary Zn-Cu ratios by using stable isotope methods in young adults and elderly subjects. Am J Clin Nutr 1989;50(6):1457-1463.