Appropriate nutrition in long-COVID-19

Metabolic dysfunction and, particularly, type 2 diabetes mellitus (T2DM) are often associated with high mortality, great severity, and worse progression of COVID-19. This association depends on diferent reasons: the overexpression of ACE2 receptor in individuals with diabetes, comorbidities such as hypertension and cardiovascular disease, obesity, and pro-infammatory state. Age, sex, and ethnicity play also a role in the disease outcome. Although it is well recognized that nutrition has a significant role in individual health, only few data have described the role of adequate alimentary regimen during long-COVID disease. Besides the well-known polyphenols derived from fruit and vegetables, biologically active and useful substances have been identifed in eggs: several egg white proteins, including ovalbumin, ovotransferrin, ovomucin, lysozyme, and avidin, as well as the peptides derived from the proteins, have been recognized for their functional importance as antimicrobial, antioxidant, and anti-infammatory agents and for their ACE-inhibitory activity (1). The role of vitamins and minerals for a correct immune system response has been fully investigated. Many nutrients, such as vitamin A, B, C, and D, and minerals like zinc, and selenium play a key role in maintaining a healthy immune system. Vitamin A is fundamental for the performances of T and B cells and for antibody production and its defciency has been associated in vivo with reduced number and functionality of natural killer cells, activity of phagocytic cells and macrophages (2). Flavonoids are a group of natural substances that have different subgroups including chalcones, flavonols, flavones, and isofavones. These molecules have many activities besides antioxidant efects and antiviral capacity. Recent research has suggested that the anti-coronavirus activity of some favonoids (herbacetin, rhoifolin, and pectolinarine) is due to the inhibition of the 3C-like protease (3). Furthermore, herbacetin, quercetin, and helichrysetin were found to be able to block the MERS-CoV/3CL pro enzymatic activity (3). In conclusion, the use of a plant-based diet and of freshly cooked and lightly processed foods, avoiding bioactive compound degradation, could help in reducing the symptoms related to long-COVID. Furthermore, data collected before the pandemic era indicated that a vegetable alimentary regimen usually reduced symptoms found in long-COVID patients such as sleep disorder, anxiety headaches, and depression.