Zinc


Why does the body need Zinc?

Zinc is an essential mineral meaning our bodies need it to function but cannot produce it and it must be consumed in our diet. The body also has no way of storing Zinc for future use so daily Zinc intake is recommend either through food or supplementation. Zinc plays a role in a wide variety of essential functions for the human body. Zinc is required for the function of at least 300 unique enzymes. Without zinc the chemical reactions catalyzed by these enzymes could not proceed.1 Zinc also supports immune function, protein synthesis, wound healing, DNA synthesis, and cell development.2,3,4,5 Suggested daily intake of Zinc for children and adults is as follows.6

Food Sources of Zinc

Food sources of Zinc include foods that are naturally high in Zinc such as seafood as well as food that are fortified with added Zinc such as some breakfast cereals. Some of the foods highest in Zinc include7:
  • Oysters (3 ounces=74mg)
  • Beef Chuck Roast (3 ounces=7.0mg)
  • Crab (3 ounces=6.5mg)
  • Beef Patty (3 ounces=5.3mg)
  • Lobster (3 ounces=3.4mg
  • Pork Chop (3 ounces=2.9mg)
As you can see most of the foods high in Zinc are meat products so vegetarians and those consuming a diet low in meat often struggle with inadequate Zinc intake2. There are also chemicals called phytates that prevent zinc from being absorbed by the body and are found in many common foods such as whole-grains, cereals, and legumes8. Studies show that even a minor zinc deficiency can begin to cause DNA damage and weaken the immune system2. For those of us who do not consume enough Zinc in our diets there are many options for supplementation.

Supplement Sources of Zinc

When choosing a zinc supplement you are looking for the amount of elemental zinc the supplement will provide the body. There are many different zinc compounds each containing a different portion of elemental zinc compared to overall weight. The following are examples of common forms of zinc available in over the counter supplements9.
  • Zinc Acetate- 30% Elemental Zinc
  • Zinc Ascorbate- 15% Elemental Zinc
  • Zinc Bisglycinate- 25% Elemental Zinc
  • Zinc Carbonate- 52% Elemental Zinc
  • Zinc Chloride- 48% Elemental Zinc
  • Zinc Citrate- 31% Elemental Zinc*
  • Zinc Gluconate- 14.3% Elemental Zinc*
  • Zinc Oxide- 80% Elemental Zinc
  • Zinc Picolinate- 20% Elemental Zinc*
  • Zinc Sulfate- 23% Elemental Zinc
  • Zinc Sulphate- 22% Elemental Zinc
*Most easily absorbed and bioavailable to the human body When looking at a zinc supplement on the shelf the amount of zinc listed is already adjusted to elemental zinc meaning a 15mg zinc picolinate supplement has the same amount of elemental zinc as a 15mg zinc citrate supplement. The one exception to this rule is zinc sulfate which you will often see labeled as Zinc 220 which is 220mg of zinc sulfate which equates to 50mg of elemental zinc. Studies have shown that zinc citrate, zinc gluconate, and zinc picolinate are some of the easiest forms of zinc for the body to absorb and they also cause less GI upset than some of the other forms of zinc.

References

  1. McCall KA, Huang C, Fierke CA. Function and mechanism of zinc metalloenzymes. J Nutr. 2000 May;130(5S Suppl):1437S-46S. doi: 10.1093/jn/130.5.1437S. PMID: 10801957.
  2. Skrajnowska D, Bobrowska-Korczak B. Role of Zinc in Immune System and Anti-Cancer Defense Mechanisms. Nutrients. 2019 Sep 22;11(10):2273. doi: 10.3390/nu11102273. PMID: 31546724; PMCID: PMC6835436.
  3. Prasad AS. Zinc: an overview. Nutrition 1995;11:93-9.
  4. Simmer K, Thompson RP. Zinc in the fetus and newborn. Acta Paediatr Scand Suppl 1985;319:158-63.
  5. Fabris N, Mocchegiani E. Zinc, human diseases and aging. Aging (Milano) 1995;7:77-93.
  6. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc . Washington, DC: National Academy Press, 2001.
  7. U.S. Department of Agriculture, Agricultural Research Service. FoodData Central , 2019.
  8. Hunt JR. Bioavailability of iron, zinc, and other trace minerals from vegetarian diets. Am J Clin Nutr 2003;78 (3 Suppl):633S-9S
  9. Saper RB, Rash R. Zinc: an essential micronutrient. Am Fam Physician. 2009 May 1;79(9):768-72. PMID: 20141096; PMCID: PMC2820120.