Micronutrients
Zinc: immune function, sources and limits
Zinc turns up in hundreds of enzymes and is one of the minerals most affected by what kind of diet you eat.
What it does
Zinc is a component of hundreds of enzymes and is required for protein synthesis, DNA synthesis, wound healing, normal growth, and immune cell development. Deficiency impairs immune function and slows wound healing, and severe deficiency stunts growth in children.[1]
How much you need
| Group | RDA | Upper limit |
|---|---|---|
| Men 19+ | 11 mg/day | 40 mg/day |
| Women 19+ | 8 mg/day | 40 mg/day |
Why plant-based diets need more
Oysters are by far the richest source, followed by red meat, poultry, beans, nuts, and whole grains. But phytates in legumes and whole grains bind zinc and reduce its absorption, so the Institute of Medicine notes that vegetarians may require as much as 50% more zinc than the RDA.[1] Soaking, sprouting, and leavening bread all reduce phytate content and improve absorption.
The upper limit matters here
Chronic high-dose zinc supplementation interferes with copper absorption and can cause copper deficiency. The 40 mg/day upper limit is not a formality — lozenges and supplements can push past it easily if taken continuously.[1]
Frequently asked questions
How much zinc do I need daily?
The RDA is 11 mg per day for adult men and 8 mg for adult women, with a tolerable upper limit of 40 mg per day for adults.
Do vegetarians need more zinc?
Yes. Phytates in legumes and whole grains bind zinc and reduce absorption, and vegetarians may require up to 50% more zinc than the RDA. Soaking, sprouting, and leavening reduce phytate content.
Can you take too much zinc?
Yes. Chronic intakes above the 40 mg per day upper limit interfere with copper absorption and can cause copper deficiency, so continuous high-dose supplementation should be avoided.
Keep reading: Vegan macros guide · Iron deficiency in athletes · Plant-based protein sources