What are Beta Glucans?

13th March 2013

By Rick Lyons, with expert comment from nutritional therapist, Sarah Barber

Find out how this little known substance could help lower your cholesterol

In chemical terms, beta glucans are chains of glucose molecules (a kind of sugar) called polysaccharides. In nutritional terms, they are classified as a dietary fibre because they are derived from the indigestible parts of plant foods.

The role of fibre

The role of dietary fibre, or roughage, is to keep the digestive system functioning properly. In particular, fibre aids the excretion of waste and toxins from the body, preventing them from sitting in the intestine or bowel for too long. As nutritional therapist, Sarah Barber says: "Fibre latches onto nasty toxic substances in our body and helps us excrete them."

Beta glucans and cholesterol

Evidence has shown beta glucans have a special role to play in helping our bodies get rid of cholesterol. "The main function that beta glucans perform is helping lower cholesterol," explains Sarah. "They do this by grabbing hold of the cholesterol and binding it with bile acids, which is then excreted from the body."

The cholesterol targeted by beta glucans includes cholesterol we have just ingested and cholesterol which has been in the body for some time. Sarah explains: "It looks at what has just come in but also at cholesterol that has built up over time - the stuff that has gone through our digestive system, through our liver and has been deposited in places like our arteries."

In 2009, the European Food Safety Authority (EFSA) Panel on Dietetic Products, Nutrition and Allergies (NDA) concluded "a cause and effect relationship has been established between the consumption of beta glucans and the reduction of blood cholesterol concentrations." This conclusion was based on a survey of existing evidence, which included a 1999 meta-analysis of 67 controlled trials. This meta-analysis found soluble fibres, such as beta glucan, "reduce total and LDL cholesterol [so-called 'bad' cholesterol in blood vessels] by similar amounts."

Health benefits of beta glucans

Research has also shown beta glucans could help modulate and stimulate the immune system. A 1994 study, published in the Annals of Surgery, found a group of high-risk surgical patients given beta glucans had significantly fewer infectious complications than those given a placebo.

Similarly, a piece of Japanese research published in 1986 found patients with advanced gastric or colorectal cancer had prolonged survival rates if given beta glucans derived from shiitake mushrooms.

Sources of beta glucans

Beta glucans are found in cereal grains such as wheat, oats, and barley - the largest concentration of which is found in the bran. Other sources include shiitake and maitake mushrooms and baker's yeast. "The RDA of beta glucans is 3-15g with the higher end having the most beneficial effect," says Sarah. "Oat porridge, for example, provides 3g.

"The sort of people who would benefit most from beta glucans are those who know they have high cholesterol or think they might be predisposed to high cholesterol because of their family history," concludes Sarah.