High-fat diets may change gut bacteria and raise risk of colorectal cancer.

High-fat diets may change gut bacteria and raise risk of colorectal cancer.

High-Fat Diets and Colorectal Cancer: The Gut Microbiome Connection


Experts have discovered that high-fat diets can have a detrimental effect on the gut microbiome, increasing the risk of colorectal cancer. A recent study involving mice revealed that high-fat diets can cause changes in gut bacteria and digestive molecules known as bile acids. However, this doesn’t mean you need to give up on delicious cheeseburgers just yet! By adopting healthy dietary practices and limiting the consumption of foods high in fat content, you can significantly reduce your risk of colorectal cancer.

The Connection between High-Fat Diets and Colorectal Cancer

Obesity has long been identified as a risk factor for colorectal cancer. A new study published in the journal Cell Reports suggests that a high-fat diet triggers changes in the digestive system that lead to inflammation and an increased prevalence of this type of cancer. The study also highlights a key protein in the gut that could potentially be targeted in anti-cancer therapies.

Dr. Anton Bilchik, the chief of medicine and the director of the gastrointestinal and hepatobiliary program at Providence Saint John’s Health Center in California, explains, “This provides a more detailed explanation of how the gut microbiome may be altered, resulting in an increase in inflammation, which is one of the current explanations for the development and progression of colorectal cancer.”

Insights from the Study on High-Fat Diets and Colorectal Cancer

In their study, researchers at the Salk Institute and the University of California San Diego fed lab mice with a genetic predisposition to colorectal cancer a high-fat diet. They closely monitored the changes in gut bacteria and bile acids — substances crucial for digesting food and absorbing cholesterol, fats, and nutrients.

The study found that the consumption of a high-fat diet increased the levels of specific gut bacteria, which, in turn, altered bile acids in a way that promoted inflammation and inhibited the replenishment of intestinal stem cells. These stem cells play a vital role in repairing cellular damage in the body. Consequently, these changes raise the risk of colorectal cancer.

Ronald Evans, a senior study author and the director of Salk’s Gene Expression Laboratory, explains, “We’ve deconstructed why high-fat diets aren’t good for you and identified specific strains of microbes that flare with high-fat diets. By knowing what the problem is, we have a much better idea of how to prevent and reverse it.”

The Role of Bile Acids in Colorectal Cancer

Previous research led by Ronald Evans showed that an increase in bile acids in the gut shuts down a protein called the farnesoid X receptor (FXR). This protein plays a role in lipid and energy metabolism and reducing inflammation. The new study on high-fat diets and colorectal cancer also revealed that changes in bile acids affect the proliferation of stem cells in the intestines.

When these stem cells replenish slowly, they are more likely to mutate and encourage the growth of colorectal cancers, as they are often the origin of such tumors. The study found that two types of gut bacteria, Ileibacterium valens and Ruminococcus gnavus, were much more prevalent in the guts of mice on high-fat diets.

The study showed that a high-fat diet has a more profound effect on the gut microbiome and bile acids than the genetic mutation that predisposes mice to colorectal cancer. Dr. Jesse P. Houghton, a senior medical director of gastroenterology at the Southern Ohio Medical Center, explains, “We’ve known that a high-fat diet, along with a diet high in red meat, tends to increase the risk of colon polyp formation and colon cancer. However, this new research links the high-fat diet with a detrimental change in the composition of the gut microbiome, leading to an increase in inflammatory bile acids, which in turn leads to a downregulation in the FXR receptor.”

Reducing Colorectal Cancer Risk

The researchers behind the study suggest that targeting the FXR receptor could be a potential intervention to prevent colorectal cancer. However, human clinical studies are still needed to further confirm the findings and potentially develop new treatments.

In the meantime, it’s important to note that up to 70% of colorectal cancer cases are preventable through adopting a healthy lifestyle, engaging in regular exercise, and following a balanced diet.

Additionally, a study published in the journal JAMA Network Open suggests that taking vitamin D supplements could help reduce the risk of relapse or death in certain types of digestive cancers, including colorectal cancer. Maintaining a normal weight and ensuring adequate vitamin D intake can improve your ability to survive cancer.

It’s clear that what we eat plays a significant role in our overall health, including cancer risk. By making conscious choices and opting for a low-fat diet, we can protect our gut microbiome, reduce inflammation, and decrease the likelihood of developing colorectal cancer. So, while it’s okay to indulge in a cheeseburger every now and then, remember to balance it out with plenty of healthy, nutritious options.