Consumption of a meal containing refined barley flour bread is associated with a lower postprandial blood glucose concentration after a second meal compared with one containing refined wheat flour bread in healthy Japanese: A randomized control trial

OBJECTIVE

Foods reducing postprandial hyperglycemia could suppress the postprandial blood glucose response after the next meal (a "second-meal" effect). However, the second-meal effect of refined barley flour bread has not been evaluated. The aim of this study is to determine whether consumption of refined barley flour bread reduces postprandial glucose concentrations after this and the subsequent meal.

METHODS

We enrolled 23 healthy young Japanese adults and conducted a randomized, double-blind, placebo-controlled, crossover study. The participants consumed refined barley flour bread containing 2.5 g β-glucan or refined wheat flour bread in a first meal, then consumed three rice balls as a second meal. Their postprandial blood glucose concentrations were measured 0, 15, 30, 45, 60, 90, and 120 min after both meals. Participants with fasting glucose concentrations above the diagnostic threshold for diabetes were excluded.

RESULTS

The blood glucose concentration 30 min after the first meal was significantly lower (P < 0.05) if refined barley flour bread (7.1 ± 1.0 mmol/L) rather than refined wheat flour bread (7.7 ± 1.2 mmol/L) was consumed. Significantly lower glucose concentrations after the second meal measured at 60 (P < 0.05, barley flour bread: 8.7 ± 1.8 mmol/L, wheat flour bread: 9.3 ± 1.7 mmol/L) and 90 min (P < 0.01, barley flour bread: 7.8 ± 1.4 mmol/L, wheat flour bread: 8.8 ± 2.1 mmol/L) were lower in participants who had previously consumed the refined barley flour bread.

CONCLUSIONS

Consumption of bread made with refined barley flour lowers postprandial blood glucose concentration after this and a subsequent meal compared with the consumption of refined wheat flour bread in healthy young Japanese adults.

Efficiency of barley bran and oat bran in ameliorating blood lipid profile and the adverse histological changes in hypercholesterolemic male rats

The efficiency of oat bran and barley bran in lowering the induced hyperlipidemia and hypercholesterolemia in blood of male Albino rats (Rattus rattus) was studied. Twenty rats were divided into four groups each consisted of five rats and fed the specified test diets for eight weeks. The first group (G1) is the negative group which was fed basal diet, the second group (G2) was fed 1.0% cholesterol, was the third group (G3) fed 1.0% cholesterol and 10% oats bran, and the fourth group (G4) was fed 1.0% cholesterol and 10% barley bran. Feeding rats on 1% cholesterol significantly increased serum total cholesterol, low density lipoprotein, and very low density lipoprotein and triglyceride and decreased serum high density lipoprotein. Furthermore, enzyme activity of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase was increased, and lipid peroxide was increased, whereas catalase and glutathione-S-transferase were decreased. Kidney functions parameters in the cholesterol supplemented group were elevated compared with the negative control. In addition, histological alteration in kidney, liver, heart, and testes was observed, compared with the negative control. Hypercholesterolemic rats supplemented with oat bran and barley bran showed significant decrease in lipid parameters, significant increase in high density lipoprotein-cholesterol, improved antioxidant enzyme, and improved histopathology of kidney, liver, heart, and testes. In conclusion, both oat bran and barley bran had protective effects against induced hyperlipidemia and improved histological alterations. Oat bran appeared more efficient than barley bran in lowering the lipid profile levels in hypercholesterolemic rats.