Ketogenic Diet May Increase Small Intestine Cancer Risk in Mouse Study

Researchers are raising questions about the long-term safety of ketogenic diets after a preclinical study found that mice fed a high-fat, low-carbohydrate eating pattern developed molecular changes in the small intestine linked to an increased risk of cancer. The findings, reported on Bioengineer.org, add a cautionary note to a diet widely promoted for weight loss and metabolic health.

What the Study Found

The research team observed that animals on a ketogenic regimen showed accelerated growth of intestinal cells lining the small bowel. According to the report, this rapid expansion occurred regardless of whether the animals lost weight, suggesting the effect was tied to the composition of the diet rather than to body mass changes alone.

Investigators also noted a rise in markers associated with tumour-promoting signalling. The authors cautioned that results from mouse models do not directly translate to people, but said the pattern warrants further investigation, particularly for individuals using the diet over extended periods.

Why the Diet May Influence Cancer Risk

Ketogenic diets sharply reduce carbohydrate intake and push the body to burn fat for fuel, producing molecules called ketone bodies. The researchers proposed that ketones may alter how stem cells in the intestinal lining divide and repair tissue.

• Reduced carbohydrate availability can change the energy balance of rapidly dividing cells.
• Ketone metabolites may interact with signalling pathways that control cell growth.
• High dietary fat itself can influence inflammation and hormone levels in the gut.

What This Means for Patients

Clinicians who recommend ketogenic eating for conditions such as epilepsy, certain metabolic disorders, or as an emerging adjunct for anorexia nervosa are being urged to weigh the potential benefits against the new safety questions. Patients using the diet alongside weight-loss medications should also be mindful of overlapping metabolic effects and broader safety protocols their clinicians follow.

The authors called for human studies to determine whether the cellular changes observed in mice appear in people who follow ketogenic diets for months or years.