Beta-glucan, a soluble fibre found in barley and oats, is believed to help lower cholesterol, a concern prevalent in Japan thanks to rising cases of metabolic syndrome in the country.
One hundred male and female Japanese subjects aged 30 to 70, each with a BMI of 24 and above, were randomly assigned to consume either a mixture of rice and high-beta-glucan barley (test group), or a mixture of rice and beta-glucan-free barley (placebo group) daily for 12 weeks.
The study stated: “Both groups showed decreases in body weight and BMI, and these changes were significantly greater in the test group. Waist circumference and visceral fat area (VFA) significantly decreased in both groups.”
"A subgroup analysis of subjects with VFA > 100cm2 showed a significant decrease in VFA in the test group, and this decrease was significantly greater than that in the placebo group.”
Apart from both groups’ regular barley intake, the study noted that their decreased VFA “is likely to have been caused by reductions in the intake of total calories and carbohydrates”, but that the significantly lower VFA in the test group was due to the presence of high-beta-glucan barley in their diets.
It added that high-beta-glucan content in one’s diet leads to increased viscosity in the human gut and “slows gastric emptying, digestion and absorption” (effects related to low-insulin and low-GI responses), and that it has “a tendency towards a reduction in LDL cholesterol”.
The latter result is “strongly related” to higher viscosity in the small intestine due to beta-glucan intake and the subsequent increase in bile acid and neutral sterol excretion, which lowers LDL cholesterol.
As such, the study suggested that the regular consumption of a rice-based dish supplemented with high-beta-glucan barley could help weight control.
Still, it was concluded that “further studies are needed to clarify the relationship between the reduction of VFA and increase in gut hormones by barley intake”.
“Effects of high beta-glucan barley on visceral fat obesity in Japanese subjects: a randomized double blind study”
Authors: Seiichiro Aoe, Yasunori Ichinose, et al.