Dietary fiber is extremely heterogeneous, so a recent study analyzed the impact of different plant-based fibers (pectin, ?-glucan, wheat dextrin, resistant starch, and cellulose as a control) on the gut microbiota in high-fat diet (HFD)-fed mice:
Only ?-glucan supplementation during HFD-feeding decreased adiposity and body weight gain and improved glucose tolerance compared with HFD-cellulose, whereas all other fibers had no effect. This was associated with increased energy expenditure and locomotor activity in mice compared with HFD-cellulose. All fibers supplemented into an HFD uniquely shifted the intestinal microbiota and cecal short-chain fatty acids; however, only ?-glucan supplementation increased cecal butyrate concentrations. Lastly, all fibers altered the small-intestinal microbiota and portal bile acid composition.
Beta-glucan is found in a number of foods:
- Oats: Whole oats, oat bran, and oatmeal are among the best sources, with about 1-2 grams of beta-glucan per 100 grams.
- Barley: Whole barley and barley products like barley flour contain 2-8 grams per 100 grams.
- Mushrooms: Certain varieties, such as shiitake, maitake, reishi, and oyster mushrooms, are rich in beta-glucans, particularly in their cell walls.
- Yeast: Nutritional yeast and baker’s yeast contain beta-glucans, often used in supplements or fortified foods.
- Seaweed: Some types, like laminarin-containing brown seaweed, provide beta-glucans.
- Rye and Wheat: Whole grain rye and wheat contain smaller amounts of beta-glucan compared to oats and barley.
Or you can buy it as a supplement.