Understanding our immune system is a complex process that is still being studied. There are many factors involved in a healthy immune system, but the onset of the COVID-19 pandemic has brought great emphasis on studying what makes certain immune systems more vulnerable than others. One cannot underestimate the role of genetic factors, diet, and a healthy lifestyle on an immune system. Yet more and more studies are discovering the effects of minor deficiencies of micro-nutrients on our immune system. Doctors are emphasizing micronutrients such as zinc, selenium, vitamin C and vitamin D, specifically Vitamin D3.

It is important to understand that vitamin D is more than just one vitamin. It is a family of nutrients that share similar chemical structures. Vitamin D is a fat-soluble vitamin that promotes the absorption of calcium, regulates bone growth, and plays a complex role in the immune function. It is considered a hormonal vitamin as your body can produce it with direct exposure to the sun. In fact, vitamin D by medical definition is itself a hormone, a group of fat-soluble secosteroids.

The body synthesizes it after sun exposure, and it is activated by the kidneys and the liver. In itself, it has the function of a hormone although we call it a vitamin as we are also able to get it from foods such as oily fish, red meat, liver, egg yolks and other animal products. The difference between vitamin D2 and D3 is essentially that vitamin D2 is derived from plant-based sources while vitamin D3 comes from animal-sourced foods. Many studies suggest that Vitamin D3 is much better at increasing the levels of vitamin D in the bloodstream.

While research on this group of nutrients called vitamin D suggest that its main purpose is for bone strength, recent research indicates that a deficiency of this complex “vitamin” may also compromise the immune function.

Vitamin D can modulate the innate and adaptive immune responses. In other words, it has a balancing effect on your immune system. Deficiency in vitamin D is associated with increased susceptibility to infection and auto-immunity.

The micro-nutrients mentioned above, zinc, selenium, vitamin C and vitamin D have a synergetic effect on your immune system. A deficiency of one can compromise the whole system. The law of minimums in biology and nutritional theory which is being applied to our immune systems suggests that your immune system is as strong as its weakest link. In this context, zinc, selenium, vitamin C and D are the micronutrients for which there is robust evidence for their immunomodulating activity. If there is a deficiency of one, even if marginal, it can compromise their metabolism and consequently their action on the immune system. Hence the importance of understanding marginal deficiency and the role on the immune system. This concept is grounded on the Triage Theory proposed by Ames building on the Law of Minimum proposed by Justus van Liebig in 1840.

Consequently, one needs to understand that a balance of these nutrients is what creates a strong immune system. It is as stated above, a complex matter but there are current clinical trials which are uncovering the importance of vitamin D3, zinc, selenium, vitamin C and their role in preventing viral infections. Furthermore, the presence of pathogens and viruses increases the demand for these micro-nutrients. As well as other unhealthy lifestyle habits such as smoking, obesity and overall a sedentary life.

Resources:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/

https://www.frontiersin.org/articles/10.3389/fnut.2020.606398/full

https://www.nytimes.com/2017/12/29/well/live/does-a-strong-immune-system-ward-off-colds-and-flu.html

https://www.news-medical.net/health/What-is-Trained-Immunity.aspx

https://www.healthline.com/nutrition/vitamin-d2-vs-d3

https://www.yourhormones.info/hormones/vitamin-d/