The Hidden Cancer Risk of Ketogenic Diets - SciTechDaily

What the report says

SciTechDaily reports that an MIT-led study in Nature found ketogenic diets may have sharply different effects in nearby parts of the digestive tract. In experiments involving mice genetically predisposed to intestinal cancer, a diet very high in fat and extremely low in carbohydrates appeared to increase tumor formation in the small intestine, even as earlier work had suggested a protective effect against tumors in the colon.

The study, led by researchers including Omer Yilmaz of MIT’s Stem Cell Initiative and Koch Institute for Integrative Cancer Research, compared mice fed a ketogenic diet with those on a control diet and an obesity-promoting high-fat, high-calorie diet. SciTechDaily says the ketogenic-fed mice did not become obese, but developed small-intestinal tumors at rates comparable to or higher than mice on the obesogenic diet.

According to the report, the tumor-promoting effect was linked not to ketone bodies such as beta-hydroxybutyrate, but to the large amount of dietary fat. Cells in the small-intestine lining increased fatty acid oxidation, activating PPAR proteins and stimulating intestinal stem cells to divide more. That process can aid tissue repair, but more stem-cell activity can also create more opportunities for abnormal growth.

The findings matter because ketogenic diets have gained attention for weight loss and possible metabolic or cancer-related benefits, while ketone supplements are also commercially popular. The article notes the researchers distinguish between high-fat ketogenic eating and ketone products, since the observed effects were tied to fat metabolism in intestinal cells. SciTechDaily says the work may be particularly relevant to people with inherited intestinal tumor risks, including familial adenomatous polyposis, though the reported experiments were in mice.