Oats contain a form of soluble fibre called oat beta-glucan which is particularly concentrated in the outer layers of the grain. Much of the research into the cholesterol lowering effects of soluble fibre has centered around oat beta glucan.
How does it work?
Because oat beta glucan is a soluble form of fibre it dissolves inside the digestive tract where it forms a thick gel – a bit like wallpaper paste. This gel is able to bind to excess cholesterol and cholesterol like substances within the gut and help to prevent these from being absorbed into the body. The gel and the cholesterol is then excretedas part of the body’s waste.
Oat beta glucan lowers cholesterol in 3 ways:
1. Preventing cholesterol in food from being absorbed
Foods provide about 20% of our cholesterol. Many of the foods that are rich in cholesterol are similar to those high in saturated fat.
2. Preventing cholesterol like substances in bile from being reabsorbed.
Bile is produced from the breakdown of cholesterol. Both bile and cholesterol are released into the gut by the body to help in the digestive process. They help the body to absorb fats from the diet. By binding to bile and cholesterol, oat beta glucan prevents them from being reabsorbed lower down the digestive tract.
3. Causing more cholesterol to be removed from the circulation
Because less cholesterol is being absorbed by the gut, the body has to take more cholesterol out of the blood stream and process it into bile to help with the digestive process. This serves to help reduce the levels of cholesterol in our body
Bioactive oat β-glucan reduces LDL cholesterol in Caucasians and non-Caucasians
There is increasing global acceptance that viscous soluble fibers lower serum LDL cholesterol (LDL-C), but most evidence for this comes from studies in Caucasians.
Thomas Wolever et al randomly assigned 367 healthy men and women aged 35 to 70 years to consume wheat bran cereal (Control), or oat β-glucan twice daily for 4 weeks. Fasting blood was obtained weekly for analysis of total and HDL cholesterol, triglycerides and calculated LDL-C.
They conclude that oat β-glucan reduces LDL-C in Caucasians and non-Caucasians!
Wolever TM, Gibbs AL, Brand-Miller J, Duncan AM, Hart V, Lamarche B, Tosh SM, Duss R. Bioactive oat β-glucan reduces LDL cholesterol in Caucasians and non-Caucasians. Nutr J. 2011 Nov 25;10:130. You can read the full report HERE
In Malaysia, products containing oat β-glucan, for eg Oat BG22, are allowed as supplements to help lower cholesterol and blood sugar