Viral infections are a global public health concern, as highlighted by annual influenza episodes and the current Covid-19 outbreak. Certain vulnerable population groups, such as elderly people and young children, can be at higher risk.
Recommendations for management of viral infections include standard public health practices (e.g. hand washing, distancing, vaccinations if available) that help reduce the spread of respiratory tract infections, as well as reliance on the body’s immune response.
Against this background, in February 2020 a panel of global experts in nutrition reviewed the role of micronutrients and omega-3 fatty acids in their support of an effective immune system*.
Studies have shown that vitamin C appears to exert a multitude of beneficial effects on cellular functions of both the innate and adaptive immune system. It seems to be able to both prevent and treat respiratory and systemic infections by enhancing various immune cell functions. Taking at least 200 mg of vitamin C per day appears to reduce the duration of cold symptoms by an average of 8% in adults and 14% in children, which translates to about one less day of illness. Note that at doses above 400 mg, vitamin C is excreted in the urine.
Vitamin D can modulate the innate and adaptive immune responses. Deficiency in vitamin D is associated with increased autoimmunity as well as an increased susceptibility to infection. Daily vitamin D supplementation raises the blood serum levels and as such lowers the risk of acute respiratory tract infections.
Zinc has important properties relevant to the immune system
Zinc deficiency affects immune cells, resulting in altered immune defense and increased risk of inflammation. The antioxidant properties of zinc help to protect immune cells. It further helps to promote the growth, maturation and activity of both innate and adaptive immune cells; and is involved in the function of several hundred enzymes. Zinc is also reported to be important to support phagocytosis (eating the pathogen), antibody production, proliferation of activated T cells, and cytokine release.
Omega-3s are essential for optimal immune function
The omega-3 fatty acids EPA and DHA help resolve inflammation, and support healing after an infection. Benefits of omega-3s have also been observed in individuals suffering from asthma and allergic respiratory diseases. In general, typical dietary intake and status of omega-3 EPA and DHA is insufficient. Your body can’t produce adequate amounts of omega-3 EPA and DHA, so it’s important to get them through the diet and by supplementation in optimal amounts.