Breath Hydrogen and Methane Responses of Men and Women to Breads Made with White Flour or Whole Wheat Flours of Different Particle Sizes

Abstract

Objective: While it is well known that consumption of whole grain foods results in beneficial health effects, the great majority of Americans prefer bread made with white flour. Consumption of whole grain foods in high fiber menus may cause undesirable intestinal responses. The purpose of this study was to determine whether consumption of bread made with ultra fine ground whole wheat flour retained beneficial effects while reducing undesirable effects.

Methods: Twenty-six men and women (31 to 55 years of age) consumed glucose solutions or bread made with white, whole wheat or fine ground whole wheat flour (1 g carbohydrate/kg body weight) in a Latin square design after two days of controlled diet. Breath methane and hydrogen were determined over the 24 hours after consumption of test foods.

Results: Hydrogen and methane responses of men and women were similar. There were no significant differences in methane responses to the different treatments, but hydrogen response was increased by all breads (p<0.0001). Although the overall mean response values were similar for all three breads, the patterns of hydrogen response differed (treatment*time, p<0.003). Gastrointestinal symptoms were not associated with fiber content or particle size of bread; however, subjects reporting symptoms tended to have higher methane responses (0.05<p<0.10).

Conclusion: Neither fiber content of bread nor particle size of whole wheat flour substantially affected breath hydrogen or methane responses or gastrointestinal symptoms. Fine ground whole wheat breads may provide a more acceptable food choice than standard whole wheat bread without sacrificing the beneficial health effects of higher fiber.

• whole grains
• fiber
• wheat
• methane
• hydrogen
• fermentation
• particle size

The authors would like to thank Evelyn Lashley, Chief Dietitian of the Human Study Facility, for her conscientious supervision of the HSF; the research cooks Linda Lynch and Sue Burns for excellent food preparation and cheerful interaction with subjects; Daniel J. Scholfield for study coordination; Willa Mae Clark and Anna van der Sluijs for analysis of the breath samples; Elisa Armero for painless phlebotomy, and all subjects who participated in the study.

Notes

Presented in part at the annual meeting of the American College of Nutrition, New York, September 27, 1997.