THE FACTS

Zinc is the second most abundant trace element in the human body after iron.   The average 70 kg adult body contains 2-3g of zinc.

Dietary sources include oysters, stone fruits and beans. However, since most plant-based zinc-containing foods contain phytates that inhibit the bioavailability of zinc, the body does not utilize zinc from plant-based foods as well as from animal foods. This is why dietitians who follow a vegan or vegetarian diet are recommended to increase the RDA by 50%.

The percentage distribution of the 2-3 grams of zinc is not even, about 60% is found in skeletal muscle and 30% in bone.
One in ten proteins in the human body has a zinc-binding site and cofactors are found in every single enzyme class. Its role is as a catalyst, structural process or signaling molecule.
It is a cofactor for nearly 300 enzymes involved in the breakdown of alcohol, alkaline phosphatase, angiotensin convertase, RNA and DNA polymerase, among others. Transcription factors that activate genes also require zinc.

The European Food Safety Authority also lists some of the beneficial properties of zinc:

• Zinc is involved in maintaining normal acid-base balance and normal carbohydrate metabolism.
• It helps to maintain normal mental function and normal blood levels of testosterone.
• It has an important role in the normal functioning of the immune system and in protecting cells against oxidative stress.
• Zinc is also involved in normal protein synthesis and the maintenance of normal fertility and reproduction.

Zinc deficiency affects more than 17% of the world’s population and has a number of consequences, for example on the normal functioning of the immune system.  2
Zinc regulates several key processes in innate immunity, including phagocytosis, intracellular degradation and cytokine production, while in the adaptive immune system, zinc deficiency results in reduced T-cell development and function and reduced antibody production by B-cells. ¹

Zinc and sport

The first recognition of an enzyme that contains zinc was carbonic anhydrase. This enzyme is responsible for the transport of Co₂  in the blood and the pH stability of the blood. With reduced zinc supply, VO₂ max and thus exercise capacity is reduced. ³

*In those individuals who were actually found to be deficient in zinc, testosterone production was also insufficient. With zinc supplementation, serum testosterone levels improved significantly.⁶
In athletes, particularly elite athletes, ongoing physical and emotional stress can significantly reduce testosterone production.In a 2007 study of elite wrestlers, zinc sulphate supplementation increased both free and bound testosterone levels.