What are Beta-Glucans?
Beta-glucans are soluble fibers, a type of dietary fiber, found in high amounts in grasses such as cereals. They are found both in the vegatative part and seeds (grains). Beta-glucans are non-starch carbohydrates made up of long chains of glucose. Beta-glucans form thick and sticky consistency. There fore, they increase the viscosity of ingested food in the gut. They are not digestible in the stomach and small intestine, but fermented in the colon and produce short fatty chain acids.
Health Benefits of Beta-Glucans
The ability of beta-glucans to increase viscosity of stomach content and their fermentation products in the colon have several health benefits. The increased viscosity of ingested food in the gut slows down digestion and emptying of gut contents. This results in lowered after meal blood glucose levels and insulin response. Human studies show that consumption of breakfast cereals and bread with oats and barley rich in beta-glucans resulted in reduced after meal blood glucose and insulin responses.
Several studies also report that meal high beta-glucans from barley and oats, like other soluble fibers, lowered LDL and total cholesterol.
Other benefits of the slow emptying of ingested food due to beta-glucans are increased sense of satiety and reduced urge to consume more calories.
Foods High in Beta-glucans
Beta-glucans are a diverse group of molecules. Their composition and content varies depending on the source and even the growth stage or condition of the source.
Beta-glucans are found in yeast, mushrooms (such as shiitake), seaweeds, and grasses. Cereal grains, such as barley and oats, are among the foods with the highest beta-glucan content. Below is a listof high beta-glucan food sources and their beta-glucan content.
| Food sources | Beta-glucans content (g/100 dry weight food) |
|---|---|
| Barley | 2 - 20 |
| Oats | 3 - 8 |
| Sorghum | 1.1 - 6.2 |
| Rye | 1.3 - 2.7 |
| Common wheat | 0.5 - 1.0 |
| Durum wheat | 0.5 - 0.6 |
| Rice | 0.13 |
Sources:
El Khoury D, Cuda C, Luhovyy BL, Anderson GH. Beta glucan: health benefits in obesity and metabolic syndrome. J Nutr Metab. 2012;2012:851362. doi:10.1155/2012/851362
Bacic A, Fincher GB, Stone BA. Chemistry, Biochemistry, and Biology of (1-3)-[beta]-Glucans and Related Polysaccharides. 1st edition. Amsterdam, The Netherlands: Academic Press; 2009.
Teas J. The dietary intake of Laminaria, a brown seaweed, and breast cancer prevention. Nutrition and Cancer. 1983;4(3):217–222