Purely anecdotally, I’ve been using beta glucan to nip colds in the bud for years. If I can catch it, just at the onset of that first tickle, one or two do the trick. But if I forget or miss it and something’s trying to settle in, I wind up taking several through the day, along with increasing my dose of vitamin C from the usual 4 grams/day to about 6-8 grams (staying home especially if I’m worried about reaching bowel tolerance).
Some research is beginning to support these anecdotes of mine and several NYBC members. One small (industry) study showed reduced number of symptoms. Another study among 182 marathoners who may be more prone to colds due to suppressed mucosal immunity after a run, showed those using the beta glucans experienced “a 37% reduction in the number of cold/flu symptom days postmarathon compared to placebo (p = .026).” In a second study by the same researchers, they observed that beta glucan use was associated with “a 32% increase in salivary IgA (p = .048) at 2 hr after exercise compared to placebo.” That might provide a partial understanding of how these compounds work to stimulate a key feature of immunity.
Others have found that higher doses (8 g/day) may help lower LDL. Clearly, more studies can help us to understand the benefits, limitations and contraindications or side effects of this intriguing polysaccharides. Would that research were run based on science and the actual needs of medicine instead of the anti-science distortions of greed!
See nybuyersclub entry on Beta Glucan