Number of vitamins (A, B6, B12, folate, C, D and E) and trace elements (zinc, copper, selenium, iron) are vital for supporting immune function. Other essential nutrients including other vitamins and trace elements, amino acids and fatty acids are also important in this regard. Thus, nutrient deficiency impairs immune function and increases susceptibility to infections and that these two outcomes can both be prevented or reversed by treating the deficiency(ies). This may be through diet or in some cases may require supplementation or some other form of therapeutic administration, depending on the nutrient, the extent of the deficiency and the setting.
The best diet to support the immune system is one with a diverse and varied intake of vegetables, fruits, berries, nuts, seeds, grains and pulses along with some meats, eggs, dairy products and oily fish. Such a diet would preclude too much processed and ‘junk’ food and excessive amounts of saturated fat and sugar. In addition to considering the ‘direct’ effects of nutrition on the immune system, many plant foods, fibre and fermented foods play a role in creating and maintaining a healthy gut microbiota that will also help to support the immune system.