LOW FAT OR A LOW CARBOHYDRATE DIETARY AND BREAST CANCER RISK

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。肥胖与患乳腺癌和许多其他癌症的风险以及心血管疾病、糖尿病、肌肉骨骼疾病和预期寿命缩短有关。建立有效的饮食和运动习惯是控制体重的基础。预防癌症或减肥最有效的饮食模式是一个有争议的话题，在科学界的各个方面都有很大的争论。低碳水化合物饮食，如阿特金斯饮食法、斯卡斯代尔饮食法和区域饮食法提倡的饮食中，碳水化合物占总热量的10%至30%，蛋白质约占总热量的40%。这个数量的蛋白质超过了美国国家科学院推荐的蛋白质占总热量的10%到35%的范围（食品和营养委员会，2002年）。低碳水化合物饮食的支持者报告说，高碳水化合物饮食会导致血浆胰岛素水平升高，促进脂肪生成。低碳水化合物饮食在普通大众中非常受欢迎，一些短期研究报告称，与富含碳水化合物但低脂肪的饮食相比，低碳水化合物饮食更能减少体脂，更能保持瘦体重（Farnsworth, 2003; Foster, 2003）。然而，只有少数研究减少碳水化合物饮食的持续时间超过6个月，长期体重维持和安全性尚不清楚。此外，已发表的研究没有利用可能是成功的关键决定因素的强化教育、反馈和监测。因此，我们建议在绝经前妇女中进行为期18个月的临床试验，强化营养和体育活动联合咨询，以检查诱导和维持体重减轻的效果。这项随机II期试点试验将为所有参与者提供密切监测的干预措施，并将低脂饮食干预与节约蛋白质（低碳水化合物）干预进行比较。我们假设卡路里限制/卡路里消耗是成功减肥的主要决定因素，而常量营养素的分布不太重要，饮食之间没有显著的长期差异。坚持每一种饮食和身体活动建议是关键的结果。这些数据将为未来更大规模的、多机构的、关于体重控制、体育活动和癌症风险因素的随机研究提供必要的可行性数据。该研究的次要目标包括一些可能与癌症相关的人体测量和生物学测量

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Obesity is linked to the risk of breast and many other cancers as well as cardiovascular disease, diabetes, musculoskeletal disorders, and reduced life expectancy. Establishing effective behaviors regarding diet and exercise are the foundations of weight control. The most effective dietary pattern for cancer prevention or weight loss is a controversial topic and the subject of great debate among various facets of the scientific community. Low carbohydrate diets such as the Atkins Diet, the Scarsdale Diet and the Zone Diet advocate a diet consisting of between 10% and 30% of total calories from carbohydrates and approximately 40% of total calories from protein. This amount of protein is exceeds the National Academy of Sciences recommended range of between 10 and 35% of total calories from protein (Food and Nutrition Board, 2002). Proponents of low carbohydrate diets report that diets high in carbohydrates result in higher plasma insulin levels and promote lipogenesis. Low carbohydrate diets have been extraordinarily popular among the general public and some short-term studies report greater loss of body fat and greater maintenance of lean body mass when compared with a diet rich in carbohydrate but low in fat (Farnsworth, 2003; Foster, 2003). However, there are only a few studies of reduced carbohydrate diets that are greater than six months in duration and long-term weight maintenance and safety are unknown. Furthermore, the published studies have not utilized intense education, feedback, and monitoring which are likely to be key determinants of success. Thus, we propose an 18-month clinical trial in premenopausal women with intensive combined nutrition and physical activity counseling to examine the efficacy in inducing and maintaining weight loss. This randomized phase II pilot trial will provide intensively monitored intervention to all participants, and will compare a low-fat dietary intervention to a protein-sparing (low carbohydrate) intervention. We hypothesize that calorie-restriction/calorie expenditure is the major determinant of successful weight loss and that macronutrient distribution is less important with no significant long-term difference between diets. Adherence to each diet and physical activity recommendations are key outcomes. These data will provide essential feasibility data for a future larger, multi-institutional, randomized study of weight control, physical activity and cancer risk factors. Secondary goals of the study include a number of anthropometric and biological measures that may be related to cancer r