Oyster mushrooms keep athletes disease free
Oyster mushrooms – Latin name: Pleurotus ostreatus – contain sugar chains that activate the immune system, and help to prevent flu and colds. A sponsored study suggests that athletes can reduce their chances of becoming ill by taking a supplement that contains oyster-mushroom extract.
Exercise, immunity & nutrition
Moderately intensive exercise stimulates the immune system, and reduces the chances of you getting a cold or flu; highly intensive exercise is more likely to overload the immune system – and therefore increases the chance of upper respiratory tract infections.
The figure below is taken from a review article by David Nieman in 1994 [Int J Sports Med. 1994 Oct;15 Suppl 3:S131-41.], and shows the relationship between exercise and the effectiveness of the immune system. It makes clear why endurance sports take a heavy toll on the immune system.
Marathon runners, triathletes and cyclists who want to avoid becoming ill – but want to continue training – can choose between two basic dietary strategies, according to a review published by Austrian nutritionists in Nutrients in 2012 [Nutrients. 2012 Sep;4(9):1187-212.].
According to the Austrians endurance athletes' first priority is to make sure that they have a balanced diet Secondly, they should consume part of their daily carbohydrate allowance – the review says six percent – during while doing their training.
So far there is insufficient scientific evidence to back up other immunomodulatory strategies, such as increasing intake of protein, BCAAs or supplementation in the form of a combination of L-cystine and L-theanine, say the Austrians.
The review does not cover phytochemicals, and therefore not pleuran either. Pleuran is an extract from oyster mushroom Pleurotus ostreatus that contains glucan. The structural formula of pleuran is shown here.
Pleuran is also the name of a Slovakian manufacturer of imunoglukan supplements. Pleuran funded a study, published in 2011 in the European Journal of Applied Physiology, in which researchers gave the Pleurotus-ostreatus extract to 25 elite athletes. [Eur J Appl Physiol. 2011 Sep;111(9):2033-40.] An equal-sized group of athletes were given a supplement containing no active ingredients for the same period of three months.
The athletes in the experimental group took two capsules of Pleurotus ostreatus extract before breakfast every day. The capsules contained 200 mg pleuran.
Before and after the supplementation period the researchers asked the athletes about whether they had been bothered by a runny nose, sore throat, cough, fatigue, headache and other symptoms that would indicate a viral infection. Each athlete was assigned a score on the basis of the answers given. The figure was significantly lower in the experimental group at the end of the supplementation period than it had been at the start.
Supplementation with the glucans in Pleurotus ostratus boosted the Natural Killer cell count in the blood. Natural Killer cells are the immune cells that spring into action first when a virus or other pathogen tries to enter your body.
Immunologists think that our immune system regards glucans and other compounds in fungi [a mushroom is a form of fungus] as a piece of membrane from a bacteria or virus, and therefore goes on high alert.
"The results from this double-blind study suggest that pleuran, insoluble beta-glucan from the Pleurotus ostreatus mushroom, supplementation may have the capacity to attenuate immune changes and decrease URTI symptoms in intensively training athletes", the researchers conclude.
Eur J Appl Physiol. 2011 Sep;111(9):2033-40.
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