Why is zinc important?

Zinc is an essential mineral that isn’t stored in significant amounts in the body so must be obtained regularly through your diet. Zinc is responsible for several biological processes in the body including immune function, protein synthesis, wound healing and supporting normal growth and development. 

A zinc deficiency can have a negative impact on several of these biological processes and may also affect reproductive function and cognitive development. Some evidence suggests that severe zinc deficiency can have a negative effect on muscle strength and function. 

While zinc deficiency is more commonly found in developing countries, those with chronic illnesses, who don’t eat a lot, or any meat, the older population and athletes, are still susceptible to becoming deficient in zinc.  

How zinc can aid muscle growth 

Among the many biological processes that zinc is responsible for, it also contributes to building and repairing muscle. Zinc is involved in hormone production, specifically testosterone which is an important component for building lean muscle mass. It has been hypothesised that zinc supplementation can help increase muscle strength and improve athletic performance by aiding skeletal muscle synthesis and regeneration. 

Having too little zinc in your body can cause a decrease in the work capacity of skeletal muscles, which can lead to impaired physical performance. In the recovery process following aerobic or strength exercise, zinc levels have been found to be depleted, this is thought to be related to the repairing process that occurs during recovery from exercise.

It has been suggested that vigorous exercise may contribute to zinc deficiency through sweat loss, so it is important to ensure your zinc levels are adequate, particularly when regularly exercising to aid muscle synthesis and regeneration. 

Daily recommended intake of zinc for males/females

The Recommended Dietary Allowance (RDA) of zinc is 11 mg for men and 8 mg for women over the age of 19. This number is an estimate of the minimum to prevent zinc deficiency, so it may be that you actually benefit from having more than the RDA.

The maximum tolerable upper limit is suggested to be 40 mg, so it is important to ensure you don’t exceed this regularly, otherwise, you may experience some negative effects. 

Sources of zinc

Foods

The best sources of absorbable zinc come from shellfish and red meats. A 100 g serving of ground beef can contain around half of the daily recommended amount, 6 oysters contain triple the recommended amount, so if you are a meat eater you should have no trouble getting the right amount of zinc.

There are some plant-based sources that do provide a relatively good amount of zinc such as nuts, seeds and legumes which can provide 10 - 40% of your daily zinc intake per serving. However, legumes contain phytates which can inhibit zinc absorption making plant-based sources of zinc less effective than animal sources.

Supplementation

If you struggle to meet the RDA for zinc then it is possible to get the nutrient through supplements. Zinc supplements usually provide between 15 and 30 mg of zinc per serving. 

To increase levels of testosterone which can contribute towards building muscle during resistance exercise, a recommended intake of zinc supplements is 30 mg a day. This amount could help you to better build lean muscle.

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References

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West, H. (2022, September 19). 10 best foods to boost your zinc intake. Healthline. https://www.healthline.com/nutrition/best-foods-high-in-zinc#TOC_TITLE_HDR_6