Scientists issue verdict as study says 1 common diet ‘may increase cancer risk’

Scientists issue verdict as study says 1 common diet ‘may increase cancer risk’ Two UK professors have issued a verdict on a new study within 24 hours of its publication Two UK scientists have issued a verdict on a new study claiming that a common diet could increase the risk of colon cancer. A new study examining the effects on mice has been published this week in Stem Cell Reports. The study, published on Thursday, November 12, concluded that one common Western diet may increase the risk of colon cancer through changes in intestinal stem cells. Now two professors have explored the claims made by the researchers at Arizona State University. The National Library of Medicine says a Western-style high-fat diet involves consuming a lot of fats and involves overeating and frequent snacking. Science Direct says such a diet includes processed foods, snacks and soft drinks, and a lack of fibres, vitamins and minerals. But could there be a link to such a diet and an increased risk of colon cancer? Twenty-four hours after the new study was issued, two UK scientists working for the Science Media Centre gave their response to the new research. Professor Dusko Ilic, Professor of Stem Cell Science, King’s College London, said it remains to be seen whether the changes seen in mice would also affect humans. He said: "This is an interesting mechanistic study of intestinal stem cells (ISCs), which reside at the base of the crypts of Lieberkühn (intestinal glands) in both the small intestine and colon. However, 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. Some changes in chromatin accessibility persisted after the mice returned to a control diet. Whether these changes contribute to colorectal cancer risk in humans remains to be established." Professor Darius Widera, Professor of Stem Cell Biology and Regenerative Medicine, University of Reading, echoed this view. He said the way the study was done meant "we cannot assume the same effects occur in people". He said: "This is an interesting study suggesting that the stem cells responsible for renewing the gut lining in mice can ‘remember’ a previous Western-style high-fat diet, potentially making them more prone to tumour growth when exposed to it again. However, the increased tumour growth was seen in mice with an introduced genetic change – the 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. Therefore, we cannot assume the same effects occur in people. "This study also does not establish that switching to a low-fat diet prevents bowel cancer in humans – the study measured changes in stem cells and the growth of experimentally triggered, early-stage tumours, rather than whether a low-fat diet reduced the likelihood of developing bowel cancer over time." Diets high in saturated fats - University of Oxford study A study funded by the British Heart Foundation found that a diet high in saturated fat - for example, processed meats and sweets - is more dangerous for the heart than a diet high in unsaturated fat, even when there has been no weight gain. Nikola Srnic, MD/DPhil Candidate at the University of Oxford, who led the research in 2024 said: “We want to study how the type of fat that a person eats affects their risk of heart and circulatory disease beyond a change in body weight. The results suggest that a diet high in saturated fat may negatively change cardiovascular disease risk factors even when a person does not gain weight. “On the other hand, we saw protective effects if a person ate a diet high in polyunsaturated fat. Although our study is ongoing, our findings so far suggest that even when you are not gaining weight, different fats can have drastically different effects on our health in a short time frame.” Current UK government guidance recommends reducing all fats in our diets and replacing saturated fats with some unsaturated fat, such as those in oily fish, olives and avocados. The Government’s Eatwell Guide recommends that people should have at least 5 portions of fruit and vegetables a day, and 6 to 8 cups or glasses of fluid a day, as well as dairy or dairy alternatives. It says people should have foods high in fat, sugar or salt less often and in smaller amounts. It advises eating some beans, pulses, fish, eggs, meat and other proteins (including 2 portions of fish every week, one of which should be oily). And it recommends basing meals on potatoes, bread, rice, pasta or other starchy carbohydrates, choosing wholegrain versions where possible.