Eating lots of button mushrooms helps Natural Killer Cells to clear up more cancer cells
A diet containing relatively large amounts of ordinary button mushrooms may offer protection against cancer. An American animal study published in 2007 in the Journal of Nutrition suggests that button mushrooms make Natural Killer Cells behave more aggressively towards cancer cells.
The researchers freeze-dried button mushrooms and ground them into a powder. They then mixed the powder with feed that they gave to mice for 10 weeks. One group of mice got feed that consisted for 2 percent of mushroom powder; another group got feed that consisted for 10 percent of mushrooms and a third group was given standard feed.
The 2-percent feed was equivalent to a diet of people who eat button mushrooms often. The 10-percent feed resembled the diet of people who use supplements containing button mushroom extracts.
At the end of the 10 weeks the researchers extracted immune cells, and therefore also Natural Killer Cells, from the mice's spleen [splenocytes]. They mixed them with cancer cells in different proportions in test tubes [target cells]. The researchers observed that eating button mushrooms boosted the number of cancer cells that were destroyed by Natural Killer Cells.
In another experiment the researchers stimulated the Natural Killer Cells with concanavalin A, a substance that the immune system identifies as a pathogen.
The Natural Killer Cells were more active if the mice had eaten button mushrooms and this was associated with higher secretions of interferon-gamma and TNF-alpha.
The researchers think that polysaccharides - indigestible sugar chains - are the active ingredient in button mushrooms.
"The results of this study demonstrate that dietary supplementation with white button mushrooms enhances Natural Killer cell activity," the researchers summarised. "This effect of mushrooms may be mediated through increased production of IFN-gamma and TNF-alpha."
"These results suggest that consumption of white button mushrooms may increase innate immunity to tumors and viral infections. Future studies are needed to determine the clinical significance of these findings, particularly in those with impaired immune functions, such as elderly, and in those with cancer."
The American ministry of agriculture and the Mushroom Council [mushroominfo.com], an organisation representing American mushroom growers, funded the study.
J Nutr. 2007 Jun;137(6):1472-7.
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