Harvie Michelle N, Howell Tony
Genesis Prevention Centre, University Hospital South Manchester National Health Service Foundation Trust, Manchester, United Kingdom
Genesis Prevention Centre, University Hospital South Manchester National Health Service Foundation Trust, Manchester, United Kingdom.
Adv Nutr. 2016 Jul 15;7(4):690-705. doi: 10.3945/an.115.011767. Print 2016 Jul.
Animal studies and human observational data link energy restriction (ER) to reduced rates of carcinogenesis. Most of these studies have involved continuous energy restriction (CER), but there is increasing public and scientific interest in the potential health and anticancer effects of intermittent energy restriction (IER) or intermittent fasting (IF), which comprise periods of marked ER or total fasting interspersed with periods of normal eating. This review summarizes animal studies that assessed tumor rates with IER and IF compared with CER or ad libitum feed consumption. The relevance of these animal data to human cancer is also considered by summarizing available human studies of the effects of IER or IF compared with CER on cancer biomarkers in obese, overweight, and normal-weight subjects. IER regimens that include periods of ER alternating with ad libitum feed consumption for 1, 2, or 3 wk have been reported to be superior to CER in reducing tumor rates in most spontaneous mice tumor models. Limited human data from short-term studies (≤6 mo) in overweight and obese subjects have shown that IER can lead to greater improvements in insulin sensitivity (homeostasis model assessment) than can CER, with comparable reductions in adipokines and inflammatory markers and minor changes in the insulin-like growth factor axis. There are currently no data comparing IER or IF with CER in normal-weight subjects. The benefits of IER in these short-term trials are of interest, but not sufficient evidence to recommend the use of IER above CER. Longer-term human studies of adherence to and efficacy and safety of IER are required in obese and overweight subjects, as well as normal-weight subjects.
动物研究和人类观察数据表明，能量限制（ER）与癌症发生率降低有关。这些研究大多涉及持续能量限制（CER），但公众和科学界对间歇性能量限制（IER）或间歇性禁食（IF）的潜在健康和抗癌作用的兴趣日益增加，IER或IF包括明显的ER期或完全禁食期，其间穿插正常进食期。本综述总结了与CER或随意进食相比，评估IER和IF对肿瘤发生率影响的动物研究。通过总结IER或IF与CER相比对肥胖、超重和正常体重受试者癌症生物标志物影响的现有人类研究，也考虑了这些动物数据与人类癌症的相关性。据报道，在大多数自发小鼠肿瘤模型中，包括1、2或3周的ER期与随意进食期交替的IER方案在降低肿瘤发生率方面优于CER。超重和肥胖受试者短期研究（≤6个月）的有限人类数据表明，与CER相比，IER可使胰岛素敏感性（稳态模型评估）得到更大改善，同时脂肪因子和炎症标志物有类似程度的降低，胰岛素样生长因子轴有微小变化。目前尚无在正常体重受试者中比较IER或IF与CER的相关数据。IER在这些短期试验中的益处值得关注，但尚无足够证据推荐使用IER而非CER。肥胖、超重以及正常体重受试者都需要开展关于IER依从性、疗效和安全性的长期人类研究。
