Diet can impact most physical functioning, so it’s no surprise that it can also play a role in immune health. Similar to the ways supplements have been studied, the focus has been on the ability of nutrients to either reduce susceptibility to infection or to enhance healing through modulating inflammation and oxidation. Current research suggests that when part of the diet, plant-based compounds such as flavonoids may reduce incidence, duration, and severity of upper respiratory infection.[1] Foods like blueberries and grapes tend to be high in flavonoids (anthocyanidins and flavonols), which have antioxidant properties that may enhance immune health. Beyond flavonoids and their antioxidant capacity, complete plant-based diets, such as the Autoimmune Protocol and vegan diets, are full of phytochemicals, fiber, vitamins, and minerals, all of which can contribute to immune health.[2] Alterations in the gut microbiome may also play a role in immune health,[3] which could explain why diets that include probiotic-rich foods, such as Kefir, have potential immune-enhancing effects