The new study, published in European Journal of Clinical Nutrition, suggests that a daily consumption of three grams of barley, containing beta-glucan can significantly reduce both total and LDL cholesterol concentrations.
“This meta-analysis of 11 studies indicates that the consumption of barley or beta-glucan from barley incorporated into different food products is associated with a significant reduction in total and LDL cholesterol concentrations.
“Increased consumption of barley products should be considered as a dietary approach to reduce LDL cholesterol concentrations,” wrote the researchers, led by Dr. Nancy Ames from the Cereal Research Centre at Agriculture and Agri-Food Canada.
In many Western countries, barley is mainly used for animal feed and malting, however there is renewed interest in barley as food due research suggesting its health benefits – including its potential to reduce the risk of cardiovascular disease through lowering cholesterol, and improving glucose tolerance.
The bioactive ingredient believed to give barley its health benefits is beta-glucan, a type of soluble fiber. Of all cereal grains, oats and barley contain the highest level of beta-glucan, with barley containing the highest levels of up to 11 percent.
Previous research has shown consumption of oats to significantly lower serum total cholesterol concentrations, and there is emerging data to support the belief that barley may have similar health benefits.
The authors noted that a number of primary studies have been carried out to test the effects of barley (or more specifically beta-glucan in barley) as a cholesterol lowering agent. However, the findings of these individual studies have been mixed, and therefore it is suggested by the researchers that a meta-analysis of existing studies “could be used to more precisely quantify the efficacy of barley and its products as lipid-lowering agents.”
Analysis of the eleven studies included found barley and beta-glucan isolated from barley significantly lowered both total and low-density lipoprotein (LDL) cholesterol concentrations.
However the ingestion of beta-glucan from barley was not seen to affect HDL cholesterol or triacylglycerol concentrations.
The researchers noted the pattern of cholesterol-lowering action from beta-glucan cannot be viewed as a dose dependent response, and instead reveals a plateau effect.
They suggested that one reason a dose-dependent response may not be observable was because of the narrow range of doses used.
The authors also noted that beta-glucan characteristics, including its solubility and molecular weight, are important determinants of its cholesterol-lowering action. Adding that highly water-soluble beta-glucan with moderate to high molecular weight may reduce serum LDL cholesterol levels better than beta-glucan with a low water solubility and low molecular weight.
The researchers concluded that increased consumption of barely products should be considered as a dietary approach to reduce LDL cholesterol concentrations.
“High consumption of beta-glucan (over 7 grams per day) did not appear to have substantially greater effects than modest consumption (between 3 and 5 grams per day). Therefore, consumption of at least 3 grams per day of barley beta-glucan will reduce blood cholesterol concentrations,” stated the authors.
Source: European Journal of Clinical Nutrition
Published online ahead of print, doi: 10.1038/jhh.2010.88
“B-glucan from barley and its lipid-lowering capacity: a meta-analysis of randomized, controlled trials”
Authors: S.S. AbuMweis, S. Jew, N.P. Ames