The novel coronavirus diseases 2019 (COVID-19) has unfolded an unprecedented worldwide public health emergency with disastrous economic consequences. Around 12 million coronavirus cases have already been identified with over half a million death. Despite numerous efforts by government as well as international organizations, these numbers are still increasing with a surprising rate. Although urgent and absolutely necessary, a reliable therapeutic or vaccine is still elusive and this status quo may remain for an uncertain period of time. Taken that into account, boosting up adaptive immunity through nutritional interventions may help subside this epidemic and save many lives. This review focuses on the nexus between a balanced diet and adaptive immunity, particularly, how poor diet may lead to compromised immunity resulting in susceptibility to the viral infections. Additionally, we discuss how nutrients (vitamins, minerals, trace elements) could be used as a tool to modulate immune response and thus impede viral infections. The study also summarized nutritional recommendations to combat COVID-19 in different countries and territories and dietary sources of those key nutrients. Moreover, different nutritional intervention strategies based on different age groups, physiological and medical conditions were also included, and the challenges of nutritional interventions towards the care of COVID-19 patient were also discussed. Since the availability of a drug or vaccine is still uncertain, a balanced diet or nutrient therapy could be used as a robust strategy to combat COVID-19. Thus, we hope this review may help to make an informed decision with regard to diet choice both at individual level as well as clinical settings.