MIT scientists report that a ketogenic diet has a surprising, region-specific effect on cancer risk in mice. In animals predisposed to intestinal tumors, the diet increased tumors in the small intestine while simultaneously reducing tumors in the colon. The contrasting outcomes within adjacent parts of the gut highlight how dietary interventions may not act uniformly along the digestive tract.
The researchers initially suspected ketones—the metabolic byproducts that define the keto diet—might drive the effect. Instead, they traced the increased risk to intestinal stem cells. The diet appears to alter stem-cell behavior in ways that differ between the small intestine and the colon, leading to opposite tumor outcomes.
The findings underscore the importance of studying diet effects across the entire gut rather than assuming a single metabolic signal applies everywhere. They also suggest that keto-style diets may carry hidden risks for certain individuals, even as they show protective effects in other contexts.