A ketogenic diet fed to mice with epithelial ovarian cancer led to significantly increased tumor growth and gut microbiome alterations, according to study recently presented at the annual meeting of the Society of Gynecologic Oncology.
“The keto diet is very popular, especially among patients who believe it may treat cancer by starving tumors of the fuel they need to grow, altering the immune system, and other anticancer effects,” said study leader Mariam AlHilli, MD, of the Cleveland Clinic.
The findings are surprising because in other studies the high-fat, zero-carb ketogenic diet has demonstrated tumor-suppressing effects. It has been under study as a possible adjuvant therapy for other cancers, such as glioblastoma, colon cancer, prostate cancer, and pancreatic cancer.
“While we don’t know yet whether these findings extend to patients, the results in animals indicate that instead of being protective, the keto diet appears to promote ovarian cancer growth and progression,” Dr. AlHilli said. In the present study, tumor bearing mice were fed a keto diet consisting of 10% protein, 0% carbohydrates, and 90% fat, while the high-fat diet was 10% protein, 15% carbohydrates, and 75% fat. The control diet consisted of 10% protein, 77% carbohydrates, and 13% fat. Epithelial ovarian cancer tumor growth was monitored weekly.
Over the 6- to 10-week course of study, a 9.1-fold increase from baseline in tumor growth was observed in the keto diet-fed mice (n = 20). Among mice fed a high-fat diet (n = 20) that included some carbohydrates, tumor growth increased 2.0-fold from baseline, and among control group mice (n = 20) fed a low-fat, high carbohydrate diet, tumor growth increased 3.1-fold.
The investigators observed several hallmarks of tumor progression: tumor associated macrophages were enriched significantly, activated lymphoid cells (natural killer cells) were significantly reduced (P < .001), and M2:M1 polarization trended higher. Also, in keto diet–fed mice, gene set enrichment analysis revealed that epithelial ovarian cancer tumors had increased angiogenesis and inflammatory responses, enhanced epithelial-to-mesenchymal transition phenotype, and altered lipid metabolism. Compared with high-fat diet–fed mice, the keto-fed mice had increases in lipid catalytic activity and catabolism, as well as decreases in lipid synthesis.
“The tumor increase could be mediated by the gut microbiome or by gene alterations or by metabolite levels that influence tumor growth. It’s possible that each cancer type is different. The composition of the diet may be a factor, as well as how tumors metabolize fat and ketones,” Dr. AlHilli said.
The results need to be confirmed in preclinical animal studies and in additional models, she added.
The study was funded by a K12 Grant and internal funding from Cleveland Clinic. Dr. AlHilli declared no relevant disclosures.