Nutrition and immunity: lessons for COVID-19

Abstract

The role of the immune system is to protect the individual against pathogenic organisms. Nutrition is one of multiple factors that determines the immune response and good nutrition is important in supporting the immune response. Immunity can be impaired in older people, particularly those who are frail, in those living with obesity, in those who are malnourished and in those with low intakes of micronutrients. The immune impairments associated with nutritional inadequacy increase susceptibility to infection and permit infections to become more severe, even fatal. The adverse impact of poor nutrition on the immune system, including its inflammatory component, may be one of the explanations for the higher risk of more severe outcomes from infection with SARS-CoV-2 seen in older people and in those living with obesity. Studies of individual micronutrients including vitamin D and zinc suggest roles in reducing severity of infection with SARS-CoV-2. Good nutrition is also important in promoting a diverse gut microbiota, which in turn supports the immune system. The importance of nutrition in supporting the immune response also applies to assuring robust responses to vaccination. There are many lessons from the study of nutrition and immunity that are relevant for the battle with SARS-CoV-2.

Nutritional interventions to augment immunity for COVID-19

“…Though Zn supplementation augments the immune systems of deficient individuals and reduces their chance of getting an infection, the benefit of supplementation for already sufficient or over supplemented individuals—the majority, remains debatable. The lower serum Zn levels observed for severe COVID-19 in studies quoted in [ 1 ] are as expected. The severity of the disease is expected to drive acute phase response reducing the free Zn levels to limit the damages to host tissues from oxidative stress [ 3 , 5 ].…”

“…Calder, P.C. has discussed the key role of good nutrition in immunity against COVID-19 [ 1 ]. It emphasizes the need for appropriate nutrition supplementation to people who are elderly, frail, and/or suffering from obesity, diabetes, malnutrition, etc., and have been adversely impacted by COVID-19.…”

Rethinking COVID-19 and Beyond: Prevention, Remedies, and Recovery

“…Vitamin D plays many roles in immune function, including cellular aspects of innate immunity, T-cell mediated immunity, B-cell mediated immunity, improved gut and skin barrier function, and others associated with antimicrobial activities (72). Low serum 25-hydroxyvitamin D (25D) concentrations, vitamin D deficiency, is another preventable global pandemic, with body fat content inversely related to serum 25D concentration and a decline in cutaneous vitamin D synthetic capacity, which is also associated with age (73)(74)(75).…”

Response to Singh and Singh

“…I thank Singh and Singh for their interest in my article [ 1 ]. However, they misinterpret the message of the article.…”

“…They summarise that the article “emphasises the need for appropriate nutrition supplementation for the old, frail, obese, diabetic, and generally malnourished, who have been adversely impacted in COVID-19” and they urge caution about micronutrient supplementation in those who are infected. In fact, the summary of my article is that “attention should be focussed on addressing current nutritional inadequacies (frailty, obesity, general undernutrition, micronutrient insufficiency or deficiency) that are widespread in the population in order to better support the immune response …for ensuring the population is better prepared for future pandemics” [ 1 ]. With regard to micronutrients, the summary of my article is that “multiple micronutrients play vital roles in supporting all aspects of the immune response and therefore their intake and status need to be considered in the context of susceptibility to SARS-CoV-2 infection and COVID-19 severity” [ 1 ].…”