Considering current pandemic of COVID-12 where no effective preventive and curative medicine available. A healthy immune system is the most important weapon against the viral infections. There are several vitamins and trace elements which are essential for the normal functioning of the immune system. Furthermore, supplementation of these have shown positive impact on enhancing immunity in viral infections. Vitamin A and D supplementation have increased the humeral immunity of paediatric patients following influenza vaccination. A high dose Zinc supplementation has shown immune enhancement of patients with torquetenovirus (TTV) . Similarly, Selenium supplementation has shown a positive response after an influenza vaccination challenge. In addition to micronutrients, several herbal and probiotics also have shown effectiveness for treatment and prevention of viral infections. Moreover, several nutraceuticals and probiotics have also shown a supportive role in enhancing immune responses.
Malnutrition increases mortality, morbidity and causes significant economic impact on the health care systems but also the economic situation of a country influences all aspects of optimal nutrition care. The increased risk of mortality and morbidity caused by malnutrition is a result of the increased rate of infections, as well as by delayed recovery. Furthermore, infections increase the demand for several nutrients. It is well-recognized that nutrition is a crucial factor in modulating immune homeostasis. Protein-energy malnutrition or even subclinical deficiencies of one micronutrient may impair one's immune responses. Recently, Calder et al. have highlighted the importance of optimal nutritional status to protect against a viral infection and Wu et al. have provided nutritional advices to reduce damages to the lungs from coronavirus and other lung infections . Acknowledging both these valuable reviews, we used a systematic searching strategy and evaluated the highest quality evidence from clinical trials for both the prevention and treatment of viral diseases by means of nutritional interventions. Priority has been given for supplementation of vitamins, trace-elements, nutraceuticals and probiotics.
In the light of the current pandemic of COVID-19, we wanted to evaluate the evidence on enhancing immunity in viral infections. This review mainly focuses on, influenza-like viral infections; however, other studies on viral infections have also been included. Finally, practical recommendations have been drawn on both preventive and therapeutic nutritional interventions for COVID-19...Continue Reading