The effect of particle size of whole-grain flour on plasma glucose, insulin, glucagon and thyroid-stimulating hormone in humans

Objective: Although it is well known that consumption of whore-grain foods with higher fiber content results in beneficial health effects, most Americ ans usually prefer bread made with white flour. Changes in bread texture an d undesirable intestinal responses have been reported as reasons for avoidi ng consumption of whole-grain foods or high-fiber menus. The purpose of thi s study was to determine whether consumption of bread made with ultra-fine- ground whole-grain wheat flour retained beneficial effects while reducing u ndesirable effects. Methods: Twenty-six men and women, 31 to 55 years of age, consumed glucose solutions or bread made with traditional white, conventional whole-grain wh eat (WWF), or ultra-fine whore-grain wheat (UFWF) flour (1 g carbohydrate/k g body weight) in a Latin square design after two days of controlled diet T he effect on glycemic response was determined by comparing blood variables, after a tolerance test with white bread, WWF bread, and UFWF bread, with t hose after a glucose tolerance test. Results: Men and women had similar responses to all tolerances except postp randial TSH. Glucose and insulin levels one half hour after the glucose loa d were significantly higher than after any of the bread tolerances. Glucose , but not insulin, areas under the curve were significantly higher after th e glucose load than areas after the three breads. Consumption of UFWF resul ted in glucose and insulin responses, as well as areas under the curve, sim ilar to those after consumption of conventional whole-wheat bread. Conclusion: The particle size of whole grain wheat flour did not substantia lly affect glycemic responses.