The ketogenic diet has become one of the world’s most popular eating plans. Originally created to manage epilepsy, the high-fat, low-carbohydrate approach has been studied for weight loss, Alzheimer’s disease, and possible effects on cancer. Despite extensive work, researchers still lack full understanding of its influence on various organs, including different sections of the digestive tract. Some investigations indicated ketogenic diets might limit certain tumors, while others showed more complex results. A new study published in Nature adds further detail. In mice genetically prone to intestinal cancer, the diet produced opposite outcomes based on location: it sped tumor growth in the small intestine but reduced tumors in the colon. The key factor was not ketone bodies, as often assumed, but how intestinal cells process dietary fat. This process activated proteins called PPARs, which increased stem cell division. While helpful for tissue repair, faster division can raise cancer risk. Mice on the ketogenic diet developed small intestinal tumors at rates similar to or higher than those on an obesity-inducing diet, yet stayed lean. The diet still suppressed colon tumors. The findings differ from a 2022 study linking protection to ketones. Instead, both effects tied to fat metabolism. The work was led by MIT researchers and highlights the need to separate dietary fat effects from ketone production. As with all mouse studies, results require further validation in other models.
