We all know the critical role of diet, exercise, and quality sleep plays at keeping a robust immune system. But what role do supplements play in contributing to the immune system? There are two supplements that you should consider; zinc and vitamin D, particularly now with the coronavirus pandemic. 

Zinc is a mineral that has many important roles in the body including cell replication, DNA synthesis, and growth. It also has a reputation for boosting immunity. Research has shown that athletes, particularly endurance athletes, tend to have deficiencies in zinc (Cordova & Alvarez-Mon, 1995). Three decades of work have indicated that zinc deficiency quickly deteriorates antibody and cell-mediated responses. Even short periods of zinc supplementation can improve immunity (Fraker et. al, 2000). Zinc supplementation has been found to reduce pneumonia in children (Lassi et. al, 2016). Moreover, it appears that zinc can directly disrupt the RNA replication process that allows for viruses to propagate (Read et. al, 2019). However, megadosing is not recommended as it can reduce copper, another mineral that aids the immune system. Foods that contain sources of zinc are meats, whole grains, liver, eggs, seafood, oysters, oatmeal, peas, beans, and maple syrup. Interestingly, lack of zinc has been associated with loss of smell and taste (Zumkley, 1985), which is a commonly reported dysfunction with coronavirus. 

Vitamin D functions to activate the immune system, and deficiencies have been correlated to increased risk of viral infections (Beard et. al, 2010). Some viruses have a lipid membrane outer coating, acting as a shield (this is called “enveloped”). Vitamin D appears to be able to disrupt the shield and break it down (Beard et. al, 2010). One study suggested that vitamin D supplementation reduced the incidence of influenza during the winter months in school children (Mitsuyoshi et. al, 2010). However, vitamin D is fat soluble, meaning that it can be toxic in high levels and RDAs (recommended daily allowances) should be followed. Food sources of vitamin D include eggs, butter, cream, halibut, fish liver oil, mackerel, salmon, sardines, and shrimp. Also, about 15 minutes of sunshine can give you adequate vitamin D. 

As always, consult with your physician if you are thinking about supplementation, as there is a such thing as toxicity and the can interact with medicine. Stay safe out there. 

References: 

Cordova, A. “Behaviour of Zinc in Physical Exercise: A Special Reference to Immunity and Fatigue.” Neuroscience & Biobehavioral Reviews, vol. 19, no. 3, 1995, pp. 439–445., doi:10.1016/0149-7634(95)00002-v.

Fraker, Pamela J., et al. “The Dynamic Link between the Integrity of the Immune System and Zinc Status.” The Journal of Nutrition, vol. 130, no. 5, Jan. 2000, doi:10.1093/jn/130.5.1399s.

Lassi, Zohra S, et al. “Zinc Supplementation for the Prevention of Pneumonia in Children Aged 2 Months to 59 Months.” Cochrane Database of Systematic Reviews, Apr. 2016, doi:10.1002/14651858.cd005978.pub3.

Zumkley, H., et al. “Zinc Metabolism during Captopril Treatment.” Hormone and Metabolic Research, vol. 17, no. 05, 1985, pp. 256–258., doi:10.1055/s-2007-1013508.

Read, Scott A, et al. “The Role of Zinc in Antiviral Immunity.” Advances in Nutrition, vol. 10, no. 4, 2019, pp. 696–710., doi:10.1093/advances/nmz013.

Beard, Jeremy A., et al. “Vitamin D and the Anti-Viral State.” Journal of Clinical Virology, vol. 50, no. 3, 2011, pp. 194–200., doi:10.1016/j.jcv.2010.12.006.

Urashima, Mitsuyoshi, et al. “Randomized Trial of Vitamin D Supplementation to Prevent Seasonal Influenza A in Schoolchildren.” The American Journal of Clinical Nutrition, vol. 91, no. 5, Oct. 2010, pp. 1255–1260., doi:10.3945/ajcn.2009.29094.