A bowl of kiwifruit may do more for digestion than the traditional advice to “eat more fiber,” according to new research from King’s College London.
In the first evidence-based dietary guidelines for chronic constipation, researchers found that certain foods and supplements, including kiwi fruit, rye bread and high mineral-content water, show meaningful benefits for adults struggling with constipation. The findings challenge older, one-size-fits-all recommendations that focused mainly on generic high-fiber diets.
The guidelines, published in both the Journal of Human Nutrition & Dietetics and Neurogastroenterology & Motility, are endorsed by the British Dietetic Association and are designed to help clinicians and individuals better manage constipation through diet.
The research team reviewed more than 75 clinical trials, using the GRADE framework to assess the quality of evidence. The resulting 59 recommendations identify foods and nutrients with the strongest support for improving stool frequency, consistency and quality of life.
“For the first time, we’ve provided direction on what dietary approaches could genuinely help, and which diet advice lacks evidence,” said Dr. Eirini Dimidi, Reader in Nutritional Sciences at King’s College London and lead author of the study. “Being able to improve this condition through dietary changes would allow people to self-manage their symptoms more and, hopefully, improve their quality of life.”
Alongside kiwifruit and rye bread, the review found benefits for psyllium fiber supplements, certain probiotic strains and magnesium oxide supplements. By contrast, traditional high-fiber diets and senna-based laxatives lacked strong supporting evidence in chronic constipation.
While the analysis offers much-needed clarity, the researchers also noted that the overall quality of existing studies remains low and that most trials focus narrowly on single ingredients rather than whole-diet patterns. That gap underscores the need for larger, better-designed studies on how overall eating habits influence digestive health.
Professor Kevin Whelan, senior author and professor of Dietetics at King’s College London, said the findings represent “a promising step toward empowering health professionals and their patients to manage constipation through diet,” adding that evidence-based guidance can “help people around the world receive up-to-date advice to improve their symptoms and well-being.”
For those seeking natural relief, the takeaway is simple: instead of loading up on generic fiber, focusing on proven foods like kiwifruit, rye bread and mineral-rich water may offer better results and a gentler approach to digestive balance.
This work was supported by the General and Education Trust Fund of the British Dietetic Association.