不限制脂肪摄入的地中海饮食可降低乳腺癌风险
2016年7月19日，美国内科医师学院官方期刊《内科学年鉴》在线发表明尼阿波利斯退伍军人医疗中心、明尼苏达大学的系统回顾与荟萃分析，发现不限制脂肪摄入的地中海饮食可降低心血管事件、乳腺癌和2型糖尿病的发病率。
地中海饮食是一种富含水果和蔬菜的饮食，不饱和脂肪酸含量较高（约占每天总热量摄入的30%～40%），尤其是橄榄油、豆类、鱼类、少到中等量乳制品和肉类产品。
作者检索了1990～2016年4月Ovid MEDLINE、CINAHL、Cochrane Library，选择对死亡率、心血管、高血压、糖尿病与依从性结局随访≥1年、人数≥100的对照试验，以及有关癌症结局的队列研究。
结果共筛选出56项研究的90篇文章。其中，对7447人（女性4282人）平均随访4.8年的西班牙大型初级预防随机单盲对照研究（PREDIMED）发现，不限制脂肪摄入的地中海式饮食可使主要心血管事件、乳腺癌和糖尿病的发病率分别降低29%、57%、30%。
Ann Intern Med. 2016 Jul 19. [Epub ahead of print]
Effects on Health Outcomes of a Mediterranean Diet With No Restriction on Fat Intake: A Systematic Review and Meta-analysis.
Bloomfield HE, Koeller E, Greer N, MacDonald R, Kane R, Wilt TJ.
Minneapolis Veterans Affairs Medical Center, Minneapolis, MN; University of Minnesota, Minneapolis, MN.
BACKGROUND: Mediterranean diets may be healthier than typical Western diets.
PURPOSE: To summarize the literature comparing a Mediterranean diet with unrestricted fat intake with other diets regarding their effects on health outcomes in adults.
DATA SOURCES: Ovid MEDLINE, CINAHL, and the Cochrane Library from 1990 through April 2016.
STUDY SELECTION: Controlled trials of 100 or more persons followed for at least 1 year for mortality, cardiovascular, hypertension, diabetes, and adherence outcomes, as well as cohort studies for cancer outcomes.
DATA EXTRACTION: Data extracted by 1 investigator was verified by another. Two reviewers assessed risk of bias and strength of evidence.
DATA SYNTHESIS: Two primary prevention trials found no difference in all-cause mortality between diet groups. One large primary prevention trial found that a Mediterranean diet resulted in a lower incidence of major cardiovascular events (hazard ratio [HR], 0.71 [95% CI, 0.56 to 0.90]), breast cancer (HR, 0.43 [CI, 0.21 to 0.88]), and diabetes (HR, 0.70 [CI, 0.54 to 0.92]). Pooled analyses of primary prevention cohort studies showed that compared with the lowest quantile, the highest quantile of adherence to a Mediterranean diet was associated with a reduction in total cancer mortality (risk ratio [RR], 0.86 [CI, 0.82 to 0.91]; 13 studies) and in the incidence of total (RR, 0.96 [CI, 0.95 to 0.97]; 3 studies) and colorectal (RR, 0.91 [CI, 0.84 to 0.98; 9 studies]) cancer. Of 3 secondary prevention studies reporting cardiovascular outcomes, 1 found a lower risk for recurrent myocardial infarction and cardiovascular death with the Mediterranean diet. There was inconsistent, minimal, or no evidence pertaining to any other outcome, including adherence, hypertension, cognitive function, kidney disease, rheumatoid arthritis, and quality of life.
LIMITATIONS: Few trials; medium risk-of-bias ratings for many studies; low or insufficient strength of evidence for outcomes; heterogeneous diet definitions and components.
CONCLUSION: Limited evidence suggests that a Mediterranean diet with no restriction on fat intake may reduce the incidence of cardiovascular events, breast cancer, and type 2 diabetes mellitus but may not affect all-cause mortality.
PRIMARY FUNDING SOURCE: Department of Veterans Affairs, Veterans Health Administration, Office of Research and Development, Quality Enhancement Research Initiative. (PROSPERO: CRD42015020262).
PMID: 27428849
DOI: 10.7326/M16-0361