P3-09-02: Intermittent Dietary Carbohydrate Restriction Enables Weight Loss and Reduces Breast Cancer Risk Biomarkers.

Abstract

Abstract Background: Energy restriction is a potential strategy for breast cancer prevention but is difficult to achieve and maintain. We found that intermittent energy restriction (2 days strict dieting week) is comparable to the standard approach of moderate daily restriction for weight loss and marginally better for improving insulin sensitivity, but no easier to follow1. In this follow on study we wished to test whether 2 novel intermittent low carbohydrate/low energy diets were feasible and easier to follow than a standard daily energy restriction. Design: Randomised comparison of 3 dietary types over 4 months in 115 overweight or obese (mean body mass index 31.0 [±5.3 SD] kg/m2) women at increased risk of breast cancer (lifetime risk > 1 in 6). Diets: 1. A restricted low carbohydrate diet (RLCD): 650 kcal and <50g carbohydrate / day for 2 days per week 2. Ad lib low carbohydrate diet (ALCD): <50g / day for 2 days per week with other food types (e.g. protein) ad lib 3. A standard daily restricted Mediterranean diet (DRMD): ∼ 1500kcal/day for 7 days per week Methods: Weight, anthropometrics, blood markers for breast cancer; insulin resistance, oxidative stress markers, leptin, adiponectin, lipids, inflammatory markers IGF-1 were assessed at baseline, 1, 3 and 4 months. Results: 88/114 completed the study (77%, drop outs 6 RLCD, 8 ALCD 12 DRMD). Last observation carried forward analyses show both intermittent low carbohydrate diets were superior to standard daily restriction for reducing weight and body fat: mean (95% confidence interval [CI]) change in body fat for RLCD was −4.3 (−5.6 to −3.0) kg, for ALCD −4.1 (−5.2 to −3.1) kg vs. −2.4 (−3.4 to −1.2) kg for DRMD (P value for difference between groups = 0.02). The intermittent groups had greater improvement in insulin resistance: mean (95% CI) change for RLCD was −22 (−35 to −11) %, ALCD −14 (−27 to −5%) % vs. −4 (−16 to 9) % for DRMD (P = 0.02). Other biomarkers are being assayed currently. Conclusion: Greater weight loss, fewer drop outs and greater reductions in insulin resistance with the novel intermittent low carbohydrate diets indicate that these are alternative approaches for energy restriction for potentially reducing risk of breast cancer and other diseases. Reference: 1Harvie MN, Pegington M, Mattson MP, Frystyk J, Dillon B, Evans G et al. The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women. Int.J Obes (Lond) 35; 714–27, 2011. This study is funded by the Genesis Breast Cancer Prevention Appeal: www.genesisuk.org Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-09-02.