Does a ketogenic diet have beneficial effects on quality of life, physical activity or biomarkers in patients with breast cancer: a randomized controlled clinical trial

INTRODUCTION: Despite recent interest in the use of ketogenic diets (KDs) for cancer, evidence of beneficial effects is lacking. This study examined the impact of a randomly assigned KD on quality of life, physical activity and biomarkers in patients with breast cancer. METHOD: A total of 80 patients with locally advanced or metastatic breast cancer and without a history of renal disease or diabetes were randomly assigned to either a KD or a control group for this 12-week trial. Concurrent with the first, third, and fifth chemotherapy sessions, quality of life, physical activity, and biomarkers (thyroid function tests, electrolytes, albumin, ammonia, ALP, lactate and serum ketones) were assessed. Dietary intake was also recorded on admission and the end of the treatment. RESULTS: No significant differences were seen in quality of life or physical activity scores between the two groups after 12 weeks; however, the KD group showed higher global quality of life and physical activity scores compared to the control group at 6 weeks (P = 0.02 P = 0.01). Also, serum lactate and ALP levels decreased significantly in the KD group compared to the control group at the end of the intervention (10.7 ± 3 vs 13.3 ± 4, 149 ± 71 vs 240 ± 164, P = 0.02 and P = 0.007, respectively). A significant inverse association was observed between total carbohydrate intake and serum beta-hydroxybutyrate at 12 weeks (r = − 0.77 P < 0.001). No significant differences between groups were observed in thyroid hormones, electrolytes, albumin, LDH or ammonia. Compliance among KD subjects ranged from 66.7 to 79.2% as assessed by dietary intake and serum ketones levels of > 0.5. CONCLUSION: According to our results, besides a higher global quality of life and physical activity scores compared to the control group at 6 weeks, KD diet combined to chemotherapy in patients with breast cancer does not bring additional benefit about quality of life and physical activity at 12 weeks. However, decreases seen in levels of lactate and ALP in the KD group suggest that a KD may benefit patients with breast cancer. TRIAL REGISTRATION: This trial has been registered on Iranian Registry of Clinical Trials (IRCT) under the identification code: IRCT20171105037259N2 https://www.irct.ir/trial/30755