Keto diet may increase risk of small intestine cancer, study reveals
A new study conducted by researchers from the Massachusetts Institute of Technology (MIT) and published in the journal Nature reveals that the ketogenic diet, widely popular for weight loss and metabolic improvement, may be associated with an increased risk of small intestine tumors, despite previous studies suggesting potential benefits in preventing colon cancer.
The ketogenic diet relies on high fat intake and very low carbohydrate consumption, forcing the body to switch from using glucose as its primary energy source to burning fat and producing ketone bodies.
Omer Yilmaz, director of the MIT Stem Cell Initiative and the study’s lead researcher, stated that the findings confirm that dietary effects can vary from one tissue to another within the same digestive tract, emphasizing the need for caution when generalizing the health benefits of any diet.
Originally developed in the 1920s to treat epilepsy, the ketogenic diet later gained popularity as a weight-loss method and potentially as a means to extend lifespan.
A previous study published in Nature in 2022 showed that one ketone body, known as beta-hydroxybutyrate (BHB), may help protect against colon cancer.
However, the new study focused on the small intestine, where researchers tested the effects of the ketogenic diet on genetically modified mice more susceptible to intestinal cancer. The results were compared with groups fed a standard diet or a high-fat, high-calorie diet.
The results showed that mice on the ketogenic diet developed small intestine tumors at higher rates than those on a traditional diet. They also exhibited similar, and sometimes higher, tumor rates compared to obese mice fed a high-fat diet.
Subsequent experiments revealed that the cause of this effect was not the ketone bodies themselves, but rather the process of “fatty acid oxidation” used by intestinal cells to extract energy from fat. Activating this process stimulates proteins known as PPARs, which in turn accelerate the division of intestinal stem cells.
Researchers note that increased stem cell activity may be beneficial for repairing the intestinal lining after injury and disease, but it can also raise the likelihood of mutations and cancerous transformations that lead to tumor formation.
Interestingly, the study observed a contrasting response in the colon: while the ketogenic diet promoted tumor growth in the small intestine, it helped reduce tumor formation in the colon, highlighting the complex effects of this diet on different parts of the digestive system.
Researcher Fantaou Chi noted that one of the key questions the team aims to answer in the future is why the same diet produces contradictory results in two adjacent organs.
The researchers pointed out that these findings do not necessarily apply to commercial ketone supplements or ketone-containing beverages, as the observed effects were linked to fat metabolism within the intestine rather than the ketone bodies themselves.
The scientific team believes these results are particularly significant given the noticeable rise in small intestine tumor rates in recent decades, especially among individuals with genetic disorders that increase susceptibility to intestinal cancer, such as familial adenomatous polyposis.
