Food bioactives, micronutrients, immune function and COVID-19
The development of targeted therapeutics against the novel coronavirus disease 2019 (COVID-19) is highly desirable but may present a challenge in the foreseeable future. Adequate nutrition is a prerequisite of an optimally functioning immune system.
Nutritional approaches, including the administration of food bioactives and micronutrients, may therefore have the potential to augment immune function and defend against COVID-19. The supplementation of micronutrients, including vitamins and trace elements, and food bioactives, such as carotenoids and polyphenols, has shown itself to be beneficial in enhancing immunity in viral infections. However, the purported significance of these compounds in naturally occurring infections derives primarily from studies using animal models. The findings of human studies are inconsistent. The efficacy of micronutrients and food bioactives in infectious diseases can be affected by a wide array of factors, including the type of pathogen, the dose, timing and duration of supplementation and the characteristics of target populations. High-dose supplementation over extended periods of time may be associated with serious adverse effects, including aggravation of infectious diseases. Evidence evaluating dietary supplementation in COVID-19 is lacking. A reliance on supplements to prevent or treat COVID-19 would therefore be premature.