In this article, a brief review of immunonutrition as a feasible alternative to modulating the immune system in defence of the SARS-CoV-2 that causes COVID-19 was presented. Immunonutrition is the nutritional practice that includes the necessary nutrients to modulate the activity of the immune system in health and disease. To date, studies are encouraging because they indicate that a good diet restores or improves the immune system's response to pathogens such as SARS-CoV-2. In addition, applying immunonutrition helps people recover with fewer sequelae after going through a serious infection in hospitalization and/or intensive care unit. Finally, it is suggested that immunonutrition be applied in conjunction with other good lifestyles and strictly following current health recommendations.

In recent decades, research into how our cells function using cellular and molecular approaches has further opened our understanding of how homeostasis is disrupted by environmental insults. Unhealthy diet over time generates a wide range of problems that lead to morbidity and mortality. Previously, the causes of diseases were attributed solely to the genetic makeup of individuals, however, epigenetics emerged to help understand how lifestyles can influence the expression of an individual's genes. Therefore, in this review article, we discuss recent evidence indicating that dietary components can modulate gene function through epigenetic control (e.g., DNA methylation, histone modifications, and microRNAs) to maintain homeostasis. In addition, it is discussed what happens when harmful nutritional habits predominant (e.g., high fat and sugar diet and low consumption of vitamins-rich foods...