JAMA Intern Med：吃素比吃肉更长寿

研究发现，素食者死于心脏病的可能性比肉食者低19%。据《美国医学会杂志•内科学》（JAMA Internal Medicine）周一发表的一项研究显示，素食者比肉食者更长寿。

研究作者对73,308名基督复临安息日会（Seventh-day Adventist Church）的成员进行了为期近六年的跟踪调查。该教会主张素食，不过并非所有的信徒都遵守这一教义。研究人员调查研究对象所吃食物的种类，然后进行随访，找出有多少研究对象去世以及死因。

研究期间，素食者死亡人数比肉食者少12%。饮食选择似乎在保护研究对象避免罹患心脏病方面发挥了重要作用。素食者死于心脏病的人数比肉食者少19%。

素食者中死于糖尿病和肾衰竭的人数似乎也比肉食者少。

热量摄入量似乎并不重要。不同的研究对象小组每日摄入的热量大体相同。研究人员发现，饮食模式给身体带来的益处与能量的摄入量无关。

素食对男性的益处比女性更明显。饮食模式对女性健康的影响似乎没有男性大。素食似乎并没有保护研究对象避免罹患癌症。素食者和非素食者罹患癌症的比例大体相同。

研究报告由位于加州洛马林达的洛马林达大学（Loma Linda University）的研究人员撰写。报告第一作者、洛马林达大学预防医学实习项目主任奥尔利奇（Michael Orlich）说，相比之前的研究，这次的研究规模更大，研究对象更加多样化。他说，人们面对各种各样的营养信息，但关键在于，你的饮食模式将如何影响你的死亡风险？

研究人员不知道素食为何似乎起到保护作用，但一个可能的原因在于素食的营养成分。素食往往纤维含量较高，饱和脂肪含量较低。奥尔利奇说，素食者往往较瘦，这是另外一个已知的对身体健康有影响的因素。他补充说，还有一个原因是研究对象饮酒和吸烟的比例都不高。

当然，仅仅不吃肉并不总是等于健康的饮食习惯。素食（比如蔬菜春卷）的脂肪和热量含量仍可能很高。此外，某些肉类也是健康的。

洛马林达大学是一所专注于医疗保健的基督复临安息日会机构。据该教会网站上的一份声明说，建议的饮食包括大量全麦面包、麦片和意大利面，不限量的新鲜蔬菜和水果，适量的豆类蔬菜、坚果和果仁。周一发布的研究由美国国立卫生研究院（National Institutes of Health）资助。

当选择一种素食生活方式时，营养学家建议需要密切注意确保主要营养的摄入是充足的。这些主要营养包括铁和锌（常含于肉中），以及钙和维生素B12。据盖洛普（Gallup）去年发布的一项调查显示，约有5%的美国人自认为是素食者。

洛马林达大学的研究人员利用一份问卷调查，根据饮食习惯将研究对象划分为不同的类别。

研究对象分类包括非素食者及被认为是半素食的人。半素食者指的是每个月食用一次以上的肉食，但每周吃肉不到一次。除肉类外，严格的素食者也不吃奶制品和蛋类。

其他类别有吃鱼的，以及不吃肉但吃奶制品和蛋类的。对很多分析项目来说，研究人员将所有这些类别统称为“素食者”。

Should We All Be Vegetarians?: Comment on “Vegetarian Dietary Patterns and Mortality in Adventist Health Study 2”
Abstract
As a graduate student studying nutrition in the early 1970s, I became a vegetarian (a lacto-ovo vegetarian, to be exact). Early observational studies had already pointed to better health outcomes on meat-free diets. Similarly, early reports suggested that meat production was wasteful and had adverse environmental impacts. The mainstream nutrition community, though, strongly resisted the growing vegetarian movement, often raising concerns about nutritional deficiencies with the most extreme types of vegetarian diets. By the time I was a third-year medical student, I had returned to eating meat, given the lack of vegetarian options in hospital cafeterias. As my clinical training and experience increased, though, I became convinced that patients in any phase of life, and with virtually any medical condition, could safely follow a meat-free diet.

Vegetarian Dietary Patterns and Mortality in Adventist Health Study 2
Abstract
Importance  Some evidence suggests vegetarian dietary patterns may be associated with reduced mortality, but the relationship is not well established.
Objective  To evaluate the association between vegetarian dietary patterns and mortality.
Design  Prospective cohort study; mortality analysis by Cox proportional hazards regression, controlling for important demographic and lifestyle confounders.
Setting  Adventist Health Study 2 (AHS-2), a large North American cohort.
Participants  A total of 96 469 Seventh-day Adventist men and women recruited between 2002 and 2007, from which an analytic sample of 73 308 participants remained after exclusions.
Exposures  Diet was assessed at baseline by a quantitative food frequency questionnaire and categorized into 5 dietary patterns: nonvegetarian, semi-vegetarian, pesco-vegetarian, lacto-ovo–vegetarian, and vegan.
Main Outcome and Measure  The relationship between vegetarian dietary patterns and all-cause and cause-specific mortality; deaths through 2009 were identified from the National Death Index.
Results  There were 2570 deaths among 73 308 participants during a mean follow-up time of 5.79 years. The mortality rate was 6.05 (95% CI, 5.82-6.29) deaths per 1000 person-years. The adjusted hazard ratio (HR) for all-cause mortality in all vegetarians combined vs nonvegetarians was 0.88 (95% CI, 0.80-0.97). The adjusted HR for all-cause mortality in vegans was 0.85 (95% CI, 0.73-1.01); in lacto-ovo–vegetarians, 0.91 (95% CI, 0.82-1.00); in pesco-vegetarians, 0.81 (95% CI, 0.69-0.94); and in semi-vegetarians, 0.92 (95% CI, 0.75-1.13) compared with nonvegetarians. Significant associations with vegetarian diets were detected for cardiovascular mortality, noncardiovascular noncancer mortality, renal mortality, and endocrine mortality. Associations in men were larger and more often significant than were those in women.
Conclusions and Relevance  Vegetarian diets are associated with lower all-cause mortality and with some reductions in cause-specific mortality. Results appeared to be more robust in males. These favorable associations should be considered carefully by those offering dietary guidance.