The effects of low-carbohydrate diets on the metabolic response to androgen-deprivation therapy in prostate cancer

Prostate cancer (PC) is the second most lethal cancer for men and metastatic PC is treated by androgen deprivation therapy (ADT). While effective, ADT has many metabolic side effects. Previously, serum metabolome analysis showed that ADT reduced androsterone sulfate, 3-hydroxybutyric acid, acyl-carnitines while increased serum glucose. Since ADT reduced ketogenesis, we speculate that low-carbohydrate diets (LCD) may reverse many ADT-induced metabolic abnormalities in animals and humans. To test this possibility, we conducted a multi-center trial of PC patients initiating ADT randomized to no diet change (control) or LCD. We previously showed LCD led to significant weight loss, reduced fat mass, improved insulin resistance and lipid profiles. To determine whether and how LCD affects ADT-induced metabolic effects, we analyzed serum metabolites after 3-, and 6-months of ADT on LCD vs. control. We found androsterone sulfate was most consistently reduced by ADT, and was slightly further reduced by LCD. Contrastingly, LCD increased 3-hydroxybutyric acid and various acyl-carnitines, counteracting their reduction during ADT. LCD also reversed the ADT-reduced lactic acid, alanine and S-adenosyl Methionine (SAM), elevating glycolysis metabolites, amino acids and sulfur-containing metabolites. While the degree of ADT-reduced androsterone was strongly correlated with glucose and indole-3-carboxaldehyde, LCD disrupted such correlation. However, many LCD-induced changes were seen at 3- but not 6-month, suggesting metabolic adaption. Together, LCD significantly reversed many ADT-induced metabolic changes while slightly enhancing androgen reduction. Future research is needed to confirm these findings and determine whether LCD can mitigate ADT-linked comorbidities and possibly delaying disease progression by further lowering androgens.