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
How can diet affect immune health?
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•Last Updated: May 16, 2025
Diet supports immune health by providing essential nutrients that help reduce infection risk and promote healing, particularly through plant compounds like flavonoids found in foods such as blueberries and grapes. Additionally, plant-based diets and probiotic-rich foods supply phytochemicals, fiber, and beneficial gut bacteria, all of which contribute to a well-functioning immune system.