Obesity Fuels Aggressive Breast Cancer: Ketogenic Diet May Do More Harm Than Good, Study Finds
A groundbreaking new study reveals a critical link between lipid levels, obesity, and the growth of triple-negative breast cancer, suggesting that commonly recommended high-fat diets like the ketogenic diet could inadvertently accelerate tumor development.
Researchers at Huntsman Cancer Institute at the University of Utah have discovered that this particularly aggressive form of breast cancer exhibits a significant “addiction” to fats, making it more prevalent and dangerous in patients with higher body mass indexes. The findings, published in Cancer & Metabolism, could reshape treatment strategies and dietary recommendations for individuals battling the disease.
The Hidden Role of Lipids in Cancer Growth
For years, the focus in cancer research has largely centered on glucose as a primary fuel source for tumors. However, this new research highlights the underestimated importance of lipids – commonly known as fats – in driving cancer progression, particularly in the context of obesity.
“The key here is that people have underestimated the importance of fats and lipids in the all-encompassing term that is obesity,” explained a senior investigator. “But our study shows that breast cancer cells are really addicted to lipids, and the abundance of lipids in patients with obesity is one of the reasons that breast cancer is more prevalent and more aggressive in these patients.”
The research team, led by investigators Amandine Chaix, Greg Ducker, and Keren Hilgendorf, conducted experiments using preclinical mouse models. They observed that both mice fed high-fat diets and those genetically engineered to have hyperlipidemia – high levels of lipids in the blood – experienced accelerated tumor growth. Importantly, this growth occurred even without the presence of other common obesity-related factors like elevated glucose and insulin.
Building Blocks for Proliferation
The mechanism behind this phenomenon appears to be surprisingly straightforward. As one researcher explained, “Lipids, which form the surface membrane of the cell, are like building blocks. If a cell receives the signal to proliferate and more building blocks are available, the tumor is going to grow more easily. We see that a high amount of lipids enables this proliferation.”
Conversely, when researchers reduced lipid levels in the mouse models, tumor growth significantly slowed, offering a potential therapeutic avenue. “We think this has therapeutic implications, because if you could just lower the lipids – which we already know how to do in patients, for example, with lipid-lowering medication – that could be a way to decelerate breast cancer growth,” a lead researcher stated. “If we can target these high levels of fat in the blood, the cancer suffers because the lipids are no longer feeding the cancer.”
Caution Advised: The Ketogenic Diet and Cancer
The study’s findings raise serious concerns about the safety of high-fat diets, particularly the ketogenic diet, for individuals with breast cancer and obesity. While the keto diet is often promoted for weight loss and metabolic health, researchers caution that it could inadvertently fuel tumor growth in susceptible patients.
“For patients who are diagnosed with breast cancer and have an elevated BMI, we would advise them to consult their physician and develop a weight loss plan as part of their treatment,” advised a researcher. “If you have high cholesterol levels to start with, think about a weight loss plan or potential pharmaceuticals that could lower your lipid levels. As our study shows, diets like keto that are very high in fat can have serious unintended side effects – even causing the tumor to grow.”
Expanding the Scope of Research
The implications of this research extend beyond triple-negative breast cancer. The team believes that lipids may also play a crucial role in fueling the growth of other cancers, including ovarian and colorectal cancers, in obese patients.
Future research will focus on evaluating how anti-lipid drugs could enhance the effectiveness of chemotherapy and gaining a deeper understanding of the precise mechanisms by which lipids support cancer cell growth. The team also acknowledges the need for further investigation using human samples and patients to validate their findings.
“While our results in mice were striking, there are clear limitations in directly projecting these findings onto human patients,” a researcher cautioned. “More research using human samples and patients will be necessary to confirm our hypotheses.”
The research was supported by the National Institutes of Health/National Cancer Institute, including cancer center support grant P30 CA042014, U01 CA272529-03S1, NCI UH2 CA286584, as well as Huntsman Cancer Foundation. Renan Vieira, a doctoral student at the U, served as the first author of the study.
