Many supplements have been proposed to help boost immune function and reduce the risk of infection. Here are just a few established and emerging supplements worth considering:
Multivitamin – Taking mega-doses of vitamins and minerals is NOT recommended. Excess intakes of some micronutrients (e.g. iron, zinc, vitamin E) can impair immune function. Taking a high quality multivitamin ONLY during periods of increased stress, fatigue or increased susceptibility to illness may help to boost immune function.
Probiotics – Probiotics such as Yakult have been shown to benefit gut health, as well as immune function by their interaction with the gut. Drink a probiotic drink such as Yakult every morning.
Glutamine – Individuals on an energy restricted diet, with a low protein intake or who are undertaking extensive endurance exercise may benefit from supplementing with the amino acid glutamine. Glutamine is known to play a role in immune function however the benefits of supplementation remain to be elucidated.
Beta-glucans – Although a relatively new supplement, research in humans is showing promising evidence. Supplementation with yeast or fungi beta-glucans may increases resistance to a wide variety of infections. Yeats derived beta-glucans has been recently shown to decrease the incidence of URTIs in marathon runners
Quercetin – The richest food sources of quercetin are onions, apples, blueberries, curly kale, hot peppers, tea, and broccoli. Supplementation with quercetin during or immediately after extensive endurance training has shown some early positive signs of reducing the risk of upper respiratory tract infection.