MONDAY, Dec. 9, 2024 (HealthDay News) -- A component of the keto diet appears to boost the powers of immunotherapy in treating cancer, a new study finds.

Beta-hydroxybutyrate (BHB), an acid produced by the body when it’s burning fat instead of blood sugar for energy, appeared to improve response in mice and humans to an immunotherapy approach called CAR T-cell therapy, researchers reported Saturday at the American Society of Hematology’s annual meeting.

Patients respond better to CAR T-cell therapy if they have higher BHB levels.

“Our theory is that CAR T-cells prefer BHB as a fuel source rather than standard sugars in our body, such as glucose,” exlained co-lead researcher Puneeth Guruprasad, a medical student at the University of Pennsylvania’s Perelman School of Medicine, in Philadelphia. “So, increasing the levels of BHB in the body gives the CAR T-cells more power to take out the cancer cells.”

CAR T-cell therapy is an innovative cancer treatment in which a person’s immune cells are drawn from their body and genetically altered in a lab, reprogrammed to target and kill their cancer.

“Thousands of patients with blood cancers have been successfully treated with CAR T-cell therapy, but it still doesn’t work for everyone,” said co-lead researcher Shan Liu, a postdoctoral fellow at the University of Pennsylvania.

“We took an outside-the-box approach to improve CAR T-cell therapy, by targeting T-cells through diet rather than further genetic engineering,” Liu added in a university news release.

In a keto diet, people eliminate nearly all carbohydrate-heavy foods, instead eating fats and proteins. As a result, their body shifts to burning fat instead of sugar for energy.

Researchers first tested the potential of a keto diet on lab mice, and found that the diet improved the ability of CAR T-cell therapy to treat lymphoma in the rodents.

Further, researchers found that higher levels of BRB created by the keto diet appeared to trigger this improvement in CAR T-cell effectiveness.

Next, they fed mice a BHB supplement alongside a normal diet and found that it boosted CAR T-cell therapy, actually causing complete obliteration of cancer in the vast majority of mice.

Blood samples from humans who’d recently undergone CAR T-cell therapy showed that the immune cells were more active if BHB levels were higher, researchers said.

Based on these results, researchers are launching a clinical trial aimed at proving that BHB supplements can boost CAR T-cell treatment.

“We’re talking about an intervention that is relatively cheap and has low toxicity potential,” said researcher Maayan Levy, an assistant professor of microbiology at the University of Pennsylvania. “If the clinical trial data pans out, I’m excited to think about how a fairly simple approach like this could be combined with dietary interventions or other, more traditional approaches, to enhance the anti-cancer effect.”

The trial will soon begin enrolling patients with large B-cell lymphoma that’s either come back or has not responded to other treatments, researchers said.

“I’m thrilled to see this research move from the lab bench to translational studies and now to a clinical trial,” said co-senior researcher Dr. Marco Ruella, scientific director of Penn Medicine’s Lymphoma Program. 

"However, we want to emphasize that, at this point, the research is still preliminary, and we’re not making any dietary or supplement recommendations to patients based on this study until we have definitive clinical evidence,” Ruella added.

Findings presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.

More information

The American Cancer Society has more on CAR T-cell therapy.

SOURCE: University of Pennsylvania, news release, Dec. 7, 2024