Are you hearing about foods and supplements that can boost your immunity? Or maybe you are wondering if there are foods that you can eat that will help you avoid getting sick from COVID-19 (corona virus.) Research into whether a particular nutrient improves immunity usually comes up with the answer “it depends.” It depends on whether studies were done in animals or humans, healthy persons or unhealthy, older persons or younger, persons with adequate nutrition or marginal nutrition, what form of nutrient was tested, what aspect of the immune system was assessed, and so on. Additionally, immunity varies a lot from person to person based on genetics, environment, lifestyle, nutrition and the interaction of these factors.
The immune system consists of a variety of tissues, specialized cells and proteins that protect the body from pathogens. We have both an innate immunity (baseline) and an adaptive immunity (response to a “foreign” cell, like a virus.) There are different types of immune system cells (click here for a chart) that work together to root out alien cells without triggering dangerous levels of inflammation. Nutrients can affect the signaling within and among these cells.
Some of the nutrients and compounds that researchers have been focusing on include vitamin D, vitamin E, zinc, omega 3 fatty acids, epigallocatechin-3-gallate (EGCG, found in green tea), polyphenols and probiotics. Research does not provide any clear evidence that supplementing with these nutrients is helpful, except in the case of deficiencies.
For those of us in the Northeast, vitamin D deficiency is not uncommon because of limited sun exposure. (In sunlight your skin is stimulated to make vitamin D.) You can get vitamin D from egg yolks, fatty fish, fortified milks/yogurt/cheese, fortified cereals, fortified juice, and fortified margarines. The RDA for people ages 1-69 is 600 IU/day; for those over 70 it is 800 IU.
Nutrition is an important factor in maintaining a healthy immune system. Because of the complex interactions of nutrients and aspects of the immune system it has been difficult for researchers to “prove” the role of any one particular nutrient. The best advice – as always! – is to eat a healthy diet with a variety of foods in an amount that maintains a healthy weight.
Consult with a health professional for questions about your individual health and care. This post is for informational purposes and is not intended to diagnose or treat any illness or nutrient deficiency.
Reference:
Wu D, Lewis ED, Pae M and Meydani SN (2019) Nutritional Modulation of Immune Function: Analysis of Evidence, Mechanisms, and Clinical Relevance. Front. Immunol. 9:3160. doi: 10.3389/fimmu.2018.03160
Yahfoufi N, Alsadi N, Jambi M, Matar C. The immunomodulatory and anti-inflammatory role of polyphenols. Nutrients 2018, 10, 1618; doi:10.3390/nu10111618
© 2020 Kathleen Searles, MS, RDN, CSSD, LD