A new study in mice looked at how the keto diet impacted cancer in mice. It sped the growth of intestinal tumors. Other research has found it may protect against colon cancer.
When we look at studies like this, we always stress the “in mice” part of the sentence. Animal studies are not human studies. Animal models are not a perfect fit for human health. While we can get insight from the research, we can’t draw firm conclusions.
The research came from MIT. Omer Yilmaz, director of the MIT Stem Cell Initiative, was the senior author of the study. Prof Yilmaz said, “Ketogenic diets have distinct effects on different tissues even within the gastrointestinal tract. I think the message here is that we need to be very careful in generalizing the effects that these diets can have, because what might be beneficial for one tissue may be detrimental for another tissue.”
The keto diet was first intended as a way to treat epilepsy in the 1920s. Many people use it to lose weight, aid longevity and help blood sugar. The diet is high-fat, low-carb, and normal or reduced protein.
The diet causes the body to burn fatty acids and create ketones. In 2022, a study suggested that the ketone BHB, created when following the diet, protects against colon cancer. The researchers wanted to see if the diet could also protect the small intestine.
The researchers used mice that were bred to be more likely to develop intestinal cancer. The mice ate a control diet, a keto diet or a high-fat, high-calorie diet. The mice eating keto were the most likely to develop intestinal tumors out of the three groups.
The research found that ketones may be playing a smaller role than thought. The dietary fat seemed to be playing its part according to Prof. Fangtao Chi. “We found that its tumor-promoting effects in the small intestine were driven by the metabolism of dietary fat rather than by ketone bodies.”
As the intestines break down fat, they activate proteins, and those proteins cause intestinal stem cells to divide rapidly. When stem cells divide, they can repair damage in the body. But they can also turn into tumors.
Prof. Jessican Shay said, “Our findings show that in this model, it's the high dietary fat content, not the ketone bodies produced during ketosis, that drives these effects on intestinal cancer, highlighting the importance of distinguishing ketogenic diets from ketone supplements.”
This research was in mice, not humans. But we always preach caution and research when it comes to the keto diet. It is a rather restrictive and extreme diet. Before making drastic changes to your diet, it’s best to talk to a health professional who is familiar with your history, needs and goals to make sure your plans are a good fit.
