Dr. Amy Nett: Beta-glucan is a glucose polymer that’s found in the cell walls of cereals. This includes oats and barley. Beta-glucans are also in certain types of mushrooms, including shiitake and maitake mushrooms. It’s also in yeasts, seaweed, and algae, certain types, and then a lesser amount is in wheat, rye, and sorghum. Those are all the foods that you would want to avoid if someone showed an intolerance to beta-glucans. Hopefully that answers that, but you can also just google “food sources of beta-glucans,” and then that will help you.