Holma, R., Hongisto, S.M., Saxelin, M., & Korpela, R. (2010). Constipation is relieved more by rye bread than wheat bread or laxatives without increased adverse gastrointestinal effects. Journal of Nutrition, 140, 534–541.
To investigate the effects of rye bread and cultured buttermilk on bowel function, colon metabolism, and gastrointestinal symptoms in adults with constipation.
For three weeks before the beginning of the study, participants were instructed not to use products containing Lactobacillus rhamnosus GG (LGG). At the end of the baseline period, participants were randomized into one of five groups.
Foods considered to have laxative effects (e.g., prunes, flax, fiber products) were only allowed for the laxative group. All participants were permitted laxative use as necessary after first contacting the principal investigator. Participants were to exclude products containing other lactic acid bacteria.
Participants collected all feces for five days during the baseline week, one day during week 1, and five days during week 3. The samples were kept frozen until taken to the study center. Sitzmarks® Radiopaque capsules were used to determine total intestinal transit time (TITT) measurements.
A metropolitan area in Helsinki, Finland
This study had a randomized, unblended, 2 x 2 factorial design (LGG given, LGG not given, rye bread given, rye bread not given).
Patients self-reported the following.
In adults with constipation, bowel function and colonic metabolism may improve more with rye bread consumption than with wheat bread consumption or common laxative use without causing adverse abdominal symptoms. Cultured buttermilk with LGG did not significantly improve bowel function or affect colonic metabolism in this population.
Rye bread consumption may be more effective in relieving constipation than wheat bread or commonly used laxatives in adults. However, the convenience sample of volunteers was small, comprised predominately men, and did not include patients with cancer. Additional study is warranted in a larger population that includes patients with cancer, as well as a balanced number of women and men.