Writing in the Journal of Nutrition, researchers from the University of Helsinki report that whole-grain rye bread performed better than laxatives and white wheat bread in the easing of symptoms of constipation, a condition reported to affects up to 27 per cent of the population of Western countries, according to the researchers.
“To the best of our knowledge, this study is the first to evaluate the effects of rye bread in treating constipation as compared with laxatives and to simultaneously investigate the changes in the colonic metabolism,” wrote the researchers, led by Reetta Holma.
“The results are encouraging,” they added.
The beneficial effects of rye were put down to its fibre content, which could fermented by bacteria in the colon, and lead to an increase in colonic short chain fatty acids (SCFA).
“Arabinoxylan, which is abundant in rye, appears to be a preferred substrate for fermentative generation of SCFA,” noted the researchers. “SCFA may induce propulsive contractions, leading to accelerated transit and relief of constipation.
“The decrease in fecal pH caused by rye bread consumption, which was found in the present study, is a natural consequence of increased fecal SCFA and also decreased intestinal transit time. The importance of maintaining a slightly acidic environment is critical, because the majority of harmful bacterial enzymes operate optimally at a neutral to slightly basic pH,” they added.
The Finnish researchers recruited 51 constipated adults and randomly assigned them to one fo five groups: One group received the whole-grain rye bread (240 grams per day), one group received buttermilk containing Lactobacillus rhamnosus GG (LGG), one group received both rye bread and LGG, the fourth group received white wheat bread, and the final group received laxatives.
At the end of the study an increase in intestinal transit time of 23 and 41 per cent was reported for the rye bread group, compared with white wheat bread and laxatives, respectively, and the average number of weekly defactions increased by 1.4.
On the other hand, LGG supplementation did not affect constipation, they noted.
“In conclusion, rye bread relieves mild constipation and improves colonic metabolism compared with white wheat bread and commonly used laxatives without increasing gastrointestinal adverse effects,” wrote Holma and her colleagues.
Source: Journal of Nutrition
Published online ahead of print, doi: 10.3945/jn.109.118570
“Constipation Is Relieved More by Rye Bread Than Wheat Bread or Laxatives without Increased Adverse Gastrointestinal Effects”
Authors: R. Holma, S.-M. Hongisto, M. Saxelin, R. Korpela