How beta-glucans in oats & barley reduce heart disease risk
How beta-glucans in oats & barley reduce heart disease risk
Researchers have found a new mechanism for how beta-glucans, found in very high amounts in oats and barley, reduce heart disease risk
University of Queensland researchers have conducted a ground breaking study that investigated the cholesterol-handling mechanisms of beta-glucans, which are found in very high levels in oats and barley grains. This ground breaking study has just been published in the high ranking biology journal, the Federation of American Societies for Experimental Biology.
Beta-glucans are a type of soluble fibre and are known to lower the risk of heart disease, but the way they do this has until now, been a mystery.
Now, Professor Mike Gidley and his Colleagues have identified a novel mechanism by which this occurs. All of this reinforces the importance of eating a diet that includes oats and grains like barley, which contain high levels of beta-glucans. The good thing about this is that including oats and barely in the diet is so easy to do, with the benefits of such diets showing up in a matter of weeks, not years.
This unique study used a very high quality animal model in pigs, an animal model very important to studying human digestion because it is very like that in humans, to get more detailed and important information than could ever be obtained from a human study.
Professor Mike Gidley and colleagues wrote that:

we demonstrated that beta-glucan added to the diet for 26 days caused a 57% decrease in LDL cholesterol [commonly known as the bad blood-cholesterol], a 34% decrease in total cholesterol and a decrease of 24% in blood total bile acids, compared to a control diet.”

Professor Gidley and colleagues added that while past human studies have shown that beta-glucans do lower levels of blood LDL-cholesterol and reduce the risk of heart disease, the detailed mechanism has not been defined, and although scientists have believed that beta-glucans prevent bile acids from being reabsorbed back into the blood, the new research shows it is not as simple as that.
Bile acids are made using cholesterol and secreted into the intestine. Having less bile acid reabsorbed is a good thing, and in the past, researchers thought that having less bile acids reabsorbed meant that extra cholesterol was mopped up when the body made more bile acids.
However, Professor Gidley and his team have found that the reduced blood cholesterol levels seen with eating beta-glucans in the diet

not only physically hinders the active reabsorption of bile acids and uptake of cholesterol, but also changes the bile acid profile with lower circulating levels …, resulting in reduced blood total cholesterol and LDL-cholesterol.”

Cholesterol absorption from the gut is also decreased.

What this means is that while the amount of bile acids circulating in the blood system decreases over a few weeks, the lower levels of blood bile acids are ultimately the result of the body making fewer bile acids, and so less cholesterol is needed by the body to make more bile acids. That’s good news.
So a diet rich in beta-glucans essentially allows the body to reset its blood bile acid levels and this ultimately reduces the body’s need for cholesterol to make more bile acids so ultimately, blood cholesterol levels go down. All this means there is less LDL-cholesterol circulating in the blood, and so less LDL-cholesterol available to do damage to the heart blood vessels.
Another important ant finding from this study is that the prebiotic activity of the beta-glucans and the changes in the gut thereof, resulted in positive changes in favourable markers of gut function.
A diet rich in beta-glucans can be achieved by eating oats and cereal grains such as barely. That is so easy to achieve for so much benefit to health.
The full manuscript details of Professor Gidley’s research:
Gunness, Michiels,Vanhaecke et al., (2016). Reduction in circulating bile acid and restricted diffusion across the intestinal epithelium are associated with a decrease in blood cholesterol in the presence of oat beta-glucan. The FASEB Journal Vol., No. , pp:, December, 2016   
The University of Queensland research was supported by the Australian Research Council Grant (CE110001007) to the Centre of Excellence in Plant Cell Walls.