Beta-glucans are a type of soluble fiber found in oats and barley, and mushrooms, as well as yeasts, bacteria, and algae. Beta-glucans are a key factor in the cholesterol-lowering effect of oats. As with other soluble fibers, beta-glucans lower circulating cholesterol levels by binding to dietary cholesterol, reducing its absorption, and by altering cholesterol metabolism, partly through effects on the gut microbiome.^1,2 A meta-analysis of results from 21 controlled trials that included a combined total of 1,120 participants with mildly elevated cholesterol levels found supplementing with a minimum of 3 grams per day of beta-glucan for at least three weeks led to reductions in total and LDL-cholesterol levels.³ In one placebo-controlled trial that included 191 subjects with borderline to very high LDL-cholesterol levels, taking 3 grams of beta-glucan daily for four weeks reduced LDL-cholesterol levels by 6% and cardiovascular risk scores by 8%.⁴ A placebo-controlled crossover trial that had 83 participants with moderately high cholesterol levels found LDL-cholesterol levels dropped 15.1%, total cholesterol levels decreased 8.9%, and non-HDL-cholesterol levels fell 12.1% after eight weeks of supplementing with 3 grams of beta-glucan daily.⁵