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Prolonged exercise or heavy training causes numerous changes in immunity and can increase the risk of infections. Nutritional supplements designed to reduce the occurrence of these infections have become increasingly popular over the last few years. One of the most promising nutritional supplements is β-glucan.

β-glucan is a polysaccharide that is found in foods such as oats, barley, mushrooms and yeasts. β-glucans vary in structure, biological activity and ability to prevent or reduce incidence of illness or infection. The majority of research over the last decade has been carried out in animal models however, emerging research has found that β-glucans are effective at modulating the immune response in adults and athletes. The origin and properties of the β-glucan is a key factor in its effectiveness however, oral ingestion of β-glucans in a supplement form has proven to be effective.

Although we don’t yet know the exact mechanisms involved in how β-glucans activate and strengthen the immune system, we do know that they do so by influencing the white blood cells called macrophages that literally devour bacteria, foreign cells, dead and dying cells, and other invaders in our bloodstream. These are the most important cells in our immune system. β-glucan supplementation activates these cells, making them more powerful and effective in attacking and consuming any foreign invader.

A study in the Journal of Sports Science and Medicine by Talbott (2009) investigated the effects of 4 weeks of supplementation of β-glucans from the yeast Saccharomyces cerevisiae on mood and upper respiratory tract infection in 75 runners, 4 weeks following a marathon. Overall, the incidence of upper respiratory tract infection and mood was significantly better in the supplement group compared to the placebo group.

A study in the European Journal of Applied Physiology by Bergendiova and colleagues (2011) investigated the effects of β-glucan from Pleurotus ostreatus on immune response in athletes. In this double blind, placebo controlled study, 50 athletes took the supplement for 3 months whilst incidence of upper respiratory tract injection and cellular immune function were monitored. The research showed that supplementation reduced the number of infections and increased the number of circulating Natural Killer cells. The authors suggested that daily supplementation of β-glucan may be beneficial for athletes undertaking heavy training phases. Unfortunately, more research is required to understand the mechanisms involved.

There is no doubt more research is required to uncover the exact mechanisms involved in the modulation of the immune system following supplementation however, the growing body of research demonstrating the health benefits are promising. This is an emerging supplement worth keeping an eye on!