Abstract 2816: Low-carbohydrate diets and prostate cancer growth: How low is “low enough”

Introduction: Previous dietary studies indicate carbohydrate intake may influence prostate cancer biology, as LAPC-4 and LNCaP xenograft mice fed a no-carbohydrate ketogenic diet (NCKD; 84% fat-0% carbohydrate-16% protein kcal) had significantly smaller tumors and longer survival times compared to mice fed a Western diet (40% fat-44% carbohydrate-16% protein kcal). The NCKD mice were also found to have higher levels of circulating IGFBP-3 and the lowest levels of insulin, IGF-1, and IGF-1:IGFBP-3 ratio despite consuming more calories than the Western group. As it is nearly impossible for a human to consume and maintain a no-carbohydrate diet similar to that in the previous xenograft studies, we sought to determine whether diets containing 10% or 20% kcal from carbohydrates could slow tumor growth in a similar manner to the NCKD in a xenograft model. METHODS: A total of 150 male SCID mice were injected with LAPC-4 cells and placed on a Western diet (35% fat-49% carbohydrate-16% protein kcal) ad libitum. Two weeks post-injection, all mice were randomized to one of three arms: NCKD, 10% carbohydrate, or 20% carbohydrate. Ten mice not injected with tumor were fed an ad libitum low-fat diet (12% fat-72% carbohydrate-16% protein kcal) and served as the reference group in a modified-paired feeding protocol for the other three groups. Calorie intake and body weights were measured thrice weekly and tumor volumes twice per week. Mice were sacrificed when tumors reached 1,000mm 3 . RESULTS: Despite consuming 5-10% extra calories on average, all mice receiving low-carbohydrate diets were significantly lighter than the mice consuming the low-fat diet (p CONCLUSIONS: LAPC-4 xenograft mice fed a low-carbohydrate diet (10-20% carbohydrate kcal) had similar survival to mice consuming a NCKD (0% carbohydrate kcal). Thus, the survival benefit of a NCKD may be achievable with less restrictive low-carbohydrate diets. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2816.