The buzz about the health benefits of oats and barley has centered on past evidence that beta-glucan-rich foods and supplements improve blood lipid (cholesterol) profiles. Oats and barley represent the major grain sources of beta-glucans (BG), the primary soluble fiber found in these plants. Some new studies, however, have contradicted the previous findings.

In one study, researchers gave participants three different doses of oatmeal or oat-bran products over the course of six weeks. The highest dose of BG (6 grams per day) was no better than the lowest dose (3.6 grams per day) at reducing LDL (bad) cholesterol. Researchers conducting another study found no positive effect on any blood-lipid marker after eight weeks of supplementing with oat bran (3 grams BG per day), and they even discovered a decrease in HDL (good) cholesterol.

At least one study shows that BG derived from barley, although less scrutinized than oat BG, may have modest lipid-lowering effects. Still, only certain people seem to respond to BG; it depends on their age, sex, and initial blood cholesterol concentration.

Supplements is written by nutrition and exercise biochemist Anthony Almada, MS. He has collaborated on more than 45 university-based studies, is co-founder of Experimental and Applied Sciences (EAS), and is founder and chief scientific officer of IMAGINutrition.