Without proper nutrition, some infections are not easily fought off by the immune system. So, how might we combat these infections with adequate nutrition? The following will highlight some of the nutritional tools we have to assist in the reduction of infection:

Fruit and Vegetables

These dietary components provide several benefits to your immune system. They provide fiber to support beneficial gut bacteria. These bacteria are the “gatekeepers” of our immune systems. They also provide essential vitamins, minerals, antioxidants, and phytochemicals that support a strong immune system.  

Vitamin C

This important antioxidant found in many fruits, vegetables, and supplements can support your health all year long.  Research has shown that vitamin C can shorten the length and severity of illness, such as the common cold or flu.  However, taking mega doses via supplementation is likely a waste and may cause gastrointestinal side effects. We are only able to absorb 500 mg at one time, so a steady diet of fruits and vegetables is your best source for reaching the tolerable upper intake level for adults of 2000 mg/day.

Vitamin D

The “sunshine vitamin” is also important in maintaining our immune system.  It is speculated that through a variety of mechanisms that low vitamin D levels may contribute to an increased rate of infection. This vitamin is found in limited amounts in fatty fish, mushrooms, dairy, eggs, and foods that are fortified with vitamin D.  You can get it from sunlight, but then you must be exposed to harmful UV rays.  The alternative is supplementation.  With the dietary reference intake at 600–800 IU and a tolerable upper intake level 4000 IU, a recommended daily dose would be 2000 IU (50 µg/d).

Vitamin E

Studies have pointed to the immunoprotective properties of vitamin E.  These studies show evidence that a deficiency of vitamin E can impair immune function. It is further known that the antioxidant actions of vitamin E have immune enhancing effects. Several foods are rich in vitamin E including green leafy vegetables, seeds, nuts and vegetable oils.

Zinc and Copper

These trace elements are critical to the immune system, important cofactors for many enzymes, and deficiencies can lead to compromised cell-mediated immunity. They are important in maintaining the integrity of DNA by modulating oxidative damage. Foods that contain zinc include meat, legumes, and dairy. Foods that contain copper include nuts, cereals and fruits.

References

Boldogh, I., Albrecht, T., Porter, D.D. (1996) Persistent Viral Infections. In: Baron S, ed. Medical Microbiology. 4th edition. Galveston (TX): University of Texas Medical Branch at Galveston. Chapter 46. Available from: https://www.ncbi.nlm.nih.gov/books/NBK8538/

Malyshkin, A.P. (2014). Chronic infections: causes and possible approach to treatment. Research Journal of Infectious Diseases; 2:3. http://dx.doi.org/10.7243/2052-5958-2-3

Zabetakis, I., Lordan, R., Norton, C., & Tsoupras, A. (2020). COVID-19: The Inflammation Link and the Role of Nutrition in Potential Mitigation. Nutrients, 12(5), 1466. https://doi.org/10.3390/nu12051466