Obesity Fuels Aggressive Breast Cancer: Ketogenic Diet May Do More Harm Than Good, Study Finds
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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.
For years, obesity has been recognized as a risk factor for numerous cancers, including breast cancer. However, the precise mechanisms driving this connection have remained elusive. This new research illuminates a key piece of the puzzle: the role of lipids – commonly known as fats – in fueling tumor growth.
“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 Keren Hilgendorf, Amandine Chaix, and Greg Ducker, 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 occurred even without the presence of other metabolic issues typically associated with obesity, such as elevated glucose and insulin levels.
Lipids as Building Blocks for Cancer Cells
The researchers propose that lipids act as essential “building blocks” for cancer cells. As one researcher explained, “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 lipid levels were reduced in the mouse models, tumor growth significantly slowed, even in the presence of high glucose and insulin. This suggests that targeting lipid metabolism could be a promising therapeutic strategy.
“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, the research suggests it could inadvertently provide fuel for tumor growth.
“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 team’s investigation doesn’t stop at triple-negative breast cancer. They hypothesize 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 mechanisms by which lipids support cancer cell proliferation.
The researchers emphasize that their findings are specific to the interaction between obesity and this particular type of cancer, and that the ketogenic diet may offer benefits for other conditions. However, this study serves as a critical reminder of the complex relationship between diet, metabolism, and cancer progression.
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.
