A study published in Stem Cell Reports on November 12 concluded that a common Western-style high-fat diet may increase the risk of colon cancer through changes in intestinal stem cells. The research, conducted by scientists at Arizona State University, examined the effects on mice.
Within 24 hours of publication, two UK professors working for the Science Media Centre gave their responses to the findings, both urging caution in interpreting the results for human health.
Expert Reactions to the Study
Professor Dusko Ilic, Professor of Stem Cell Science at King's College London, said it remains to be seen whether the changes observed in mice would also affect humans. He described the research as an interesting mechanistic study of intestinal stem cells, which reside at the base of the crypts of Lieberkühn in both the small intestine and colon.
However, he noted that the experiments were conducted in mice and focused on the small intestine. "The study therefore does not show that a high-fat diet causes colon cancer in people, or that changing diet reverses cancer risk," he said. He added that some changes in chromatin accessibility persisted after the mice returned to a control diet, but whether these changes contribute to colorectal cancer risk in humans remains to be established.
Limitations Highlighted by Second Expert
Professor Darius Widera, Professor of Stem Cell Biology and Regenerative Medicine at the University of Reading, echoed this view, saying the way the study was done meant "we cannot assume the same effects occur in people."
He explained that the increased tumour growth was seen in mice with an introduced genetic change, where researchers switched off a gene called Apc specifically in the gut stem cells. "Apc normally helps keep cell growth under control, so switching it off allowed them to examine how diet affected early tumour growth," he said.
Professor Widera also stressed that the study does not establish that switching to a low-fat diet prevents bowel cancer in humans, as it measured changes in stem cells and the growth of experimentally triggered early-stage tumours rather than long-term cancer likelihood.
Background on Western Diets and UK Guidance
The National Library of Medicine describes a Western-style high-fat diet as involving a lot of fats, overeating, and frequent snacking. Science Direct notes such a diet includes processed foods, snacks, and soft drinks, with a lack of fibres, vitamins, and minerals.
Current UK government guidance recommends reducing all fats in diets and replacing saturated fats with some unsaturated fat, such as those in oily fish, olives, and avocados. The Eatwell Guide advises at least 5 portions of fruit and vegetables a day, 6 to 8 cups or glasses of fluid daily, and dairy or dairy alternatives, while limiting foods high in fat, sugar, or salt.
