Vegetarians often lack zinc
- and supplements strengthen their immune system
Zinc is crucial for the immune system on multiple fronts. Animal-based foods such as meat and eggs are the best sources, as zinc from plant-based sources is less readily absorbed. As a result, vegetarians and vegans often have insufficient zinc intake. On the other hand, zinc supplementation can enhance the production of interferon and other components of the immune system, which are particularly important for defending against viral infections. This is highlighted in a study published in Clinical Nutrition. It is also important to note that aging and certain medications can increase the risk of zinc deficiency.
Plant-based diets have become increasingly popular for various reasons. However, this also means that deficiencies in several essential nutrients have become more widespread, partly because some nutrients are found almost exclusively in animal-based foods. Additionally, it is more difficult to utilize minerals such as iron, calcium, magnesium, and zinc from plant foods. This is due to the presence of phytates in plants, especially whole grains, which bind these minerals and reduce their absorption in the gut.
As plant-based diets have grown in popularity, and even mild zinc deficiencies can impair immune function, researchers have become increasingly interested in the role of zinc deficiency for innate immunity in vegetarians and vegans. The innate immune system, composed of various white blood cells and proteins, fights most pathogens. When a virus infects cells, these cells should initially release proteins such as interferon-α, which both prevent viral replication and activate other defense mechanisms in the body. In the introduction to the new study, the researchers describe how interferon-α is produced through various signaling pathways and gene activation.
Previous in vitro studies have shown that zinc can increase interferon production, but the underlying mechanisms were unclear. The aim of the new study was therefore to describe the immunological, antiviral, and molecular mechanisms underlying zinc-dependent interferon production.
Using food frequency questionnaires (FFQs) and blood zinc measurements, the researchers assessed zinc status in a group of 18-35-year-olds who were omnivores, vegetarians, or vegans. The antiviral interferon-α response in whole blood samples and different white blood cells was measured after viral stimulation. The scientists also measured the expression of interferon regulatory factor 3 (IRF3), which regulates genes involved in interferon-α production.
Participants who were zinc-deficient received a daily zinc supplement of 10 mg for 14 days. Tests were then repeated to assess the effect of supplementation. The researchers observed a particularly high prevalence of zinc deficiency among vegetarians and vegans. Compared with omnivores, vegetarians and vegans had a reduced interferon-α response and lower IRF3 levels.
Zinc deficiency and impaired interferon production can therefore weaken the innate immune system, particularly increasing susceptibility to viral infections. The study also showed that zinc supplementation effectively increased zinc status, boosted IRF3 expression, and consequently enhanced interferon-α production.
According to the researchers, it is especially important to focus on the growing number of vegetarians and vegans, as they risk deficiencies in several essential nutrients. Relevant supplementation, including zinc, may therefore be necessary for those who continue eating a plant-based diet. It is also important to remember that zinc is involved in hundreds of enzymatic processes, and deficiencies can lead to reduced fertility, low mood, and problems with skin, hair, nails, vision, hearing, taste, and appetite.
Note: Widespread zinc deficiency in multiple populations
The new study aligns with a previous review article published in Immunometabolism, which describes in more detail zinc’s role in interferon production and other parts of the immune system. Deficiencies particularly increase the risk of influenza, COVID-19, pneumonia, and other respiratory diseases. It is also problematic that many older adults have low zinc intake, and aging itself impairs absorption. Diuretics, birth control pills, and vitamin B6 deficiency can also reduce zinc utilization.
References:
Fynn Vallboehemer et al. Zinc supplementation among zinc-deficient vegetarians and vegans restores antiviral interferon-α response by upregulating interferon regulatory factor 3. Clinical Nutrition 2025
Jonathan H Yao et al. Impact of zinc on immunometabolism and its putative role on respiratory diseases. Immunometabolism. 2025
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