The Role of Micronutrients in Support of the Immune Response against Viral Infections

Abstract

Viral infections are a leading cause of morbidity and mortality worldwide, and the importance of public health practices including handwashing and vaccinations in reducing their spread is well established. Furthermore, it is well known that proper nutrition can help support optimal immune function, reducing the impact of infections. Several vitamins and trace elements play an important role in supporting the cells of the immune system, thus increasing the resistance to infections. Other nutrients, such as omega-3 fatty acids, help sustain optimal function of the immune system. The main aim of this manuscript is to discuss of the potential role of micronutrients supplementation in supporting immunity, particularly against respiratory virus infections. Literature analysis showed that in vitro and observational studies, and clinical trials, highlight the important role of vitamins A, C, and D, omega-3 fatty acids, and zinc in modulating the immune response. Supplementation with vitamins, omega 3 fatty acids and zinc appears to be a safe and low-cost way to support optimal function of the immune system, with the potential to reduce the risk and consequences of infection, including viral respiratory infections. Supplementation should be in addition to a healthy diet and fall within recommended upper safety limits set by scientific expert bodies. Therefore, implementing an optimal nutrition, with micronutrients and omega-3 fatty acids supplementation, might be a cost-effective, underestimated strategy to help reduce the burden of infectious diseases worldwide, including coronavirus disease 2019 (COVID-19).

Could nutritional supplements act as therapeutic adjuvants in COVID-19?

“…VD supplementation has demonstrated efficacy in the prevention of acute respiratory infections, with the most significant results observed in patients receiving daily or weekly VD doses [5]. Moreover, different authors have demonstrated that people with VD insufficiency (25OHD < 30 ng/ml) or deficiency (25OHD < 20 ng/ml) have a higher risk of developing respiratory infections [6]. With specific regard to COVID-19, it is important to underline that the disease has mainly spread in winter when is more probable to observe VD deficiency and that the severity of COVID-19 has shown a north-south gradient, being more pronounced in latitudes associated with a deficient VD status 4 .…”

“…Therefore, its wide-spectrum immunomodulatory action allows the hypothesis of the utility of VD supplementation in COVID-19, both for the prevention of the progression to the severe manifestations of the disease and for the reduction of the transmission of the infectious agent. Data deriving from previous studies analyzing the role of VD supplementation in the prevention and treatment of respiratory infections are markedly heterogeneous, as the baseline VD levels of the population examined and the posology of VD are not standardized [6]. However, in most of the trials on pediatric patients, the intervention consists of a daily intake of 400-1200 IU of VD [5,6,13].…”

“…Data deriving from previous studies analyzing the role of VD supplementation in the prevention and treatment of respiratory infections are markedly heterogeneous, as the baseline VD levels of the population examined and the posology of VD are not standardized [6]. However, in most of the trials on pediatric patients, the intervention consists of a daily intake of 400-1200 IU of VD [5,6,13]. Therefore, a supplementation within this posology range, individualized considering the patient's risk factor and baseline 25OHD levels, can be suggested for the prevention of COVID-19 ( Table 1).…”

“…Therefore, a supplementation within this posology range, individualized considering the patient's risk factor and baseline 25OHD levels, can be suggested for the prevention of COVID-19 ( Table 1). On the other hand, the use of short-term regimens of high-dose VD in patients with respiratory infections has not demonstrated a significant beneficial effect [6]. The importance of VD supplementation could be even more pronounced during winter and in geographic areas at a high prevalence of VD deficiency.…”

Mediterranean Diet for the Prevention of Gestational Diabetes in the Covid-19 Era: Implications of Il-6 In Diabesity

“…It is well known that omega-3 polyunsaturated fatty acids (omega-3 PUFA), vitamins (folate, A, B6, B12, C, D, and E) and minerals (copper, iron, magnesium, selenium, and zinc), improve the immune system [ 167 , 168 , 169 , 170 , 171 , 172 , 173 ]. Although supplementations with omega-3 PUFA and/or micronutrients have been suggested to improve clinical outcomes of patients with ARDS [ 174 , 175 , 176 , 177 ] and to improve public health [ 167 , 177 ], it has been pointed out that only individuals at high-risk of specific nutrient deficiencies could benefit from supplementation, whereas the supplementation of a single nutrient is not promising in the general population [ 178 ]. Moreover, it has been recently found that zinc supplementation in pregnant women decreased hemoglobin concentration [ 179 ].…”