摘要：适度地减少食盐摄入量不会降低人们死亡或罹患心血管疾病的可能性。这是发表在最新一期《科克伦图书馆》（The Cochrane Library）上的一篇系统评价得出的主要结论。
很多证据表明减少食盐的摄入量会降低血压，而且研究人员也确实见到了这样的情况发生。“对减少食盐摄入量的强力支持与鼓励确实会在六个多月之后引起食盐摄入量的减少以及血压的轻微降低。”，在英国埃克塞特大学（University of Exeter）半岛医学及牙科学院工作的第一作者Rod Taylor教授说道。
“我们希望看到的是这种摄入量的变化是否也会降低人们死亡或罹患心血管疾病的风险。”，Taylor说道。
2004年发表的一篇有关饮食建议的Cochrane评价没有能够找到足够的证据来使研究人员得出任何有关减少食盐摄入量对死亡率或心血管疾病发生率的影响的结论。但是，在Taylor最新发表的研究中，其研究团队成功地找出了共包括6489名参与者的七项研究。这为能够得出结论提供了足够多的数据。即便如此，Taylor认为他还需要获得至少18000名受试者的数据才有可能发现任何显而易见的健康益处。
大多数专家都同意食用过多的盐对身体不好，减少食盐摄入量对于具有正常和较高血压的人来说是有益处的。“我们认为，我们在这项研究中没有看到太大的益处，因为我们在试验中所分析的受试者只是适度地降低了他们的食盐摄入量，所以对血压和心脏病的影响不是很大。”，Taylor解释道。他认为保健从业人员需要找到降低食盐摄入量的更多可行且廉价的有效方法。
许多国家的政府都提出建议，呼吁人们降低食用钠盐的摄入量。在英国，“国家健康与临床指导研究所（National Institute of Health and Clinical Guidance，NICE）”最近提倡人们加快降低食盐摄入量，目标是从2015年每名成年人每天6克的最大摄入量减少到2025年的3克。
“随着政府设定越来越低的食盐摄入量标准以及食品生产商致力于产品的去盐化，我们非常有必要进行一些大规模的研究试验以充分了解减少食盐摄入量的益处和风险。”，Taylor说道。
生物探索推荐英文论文摘要：
Reduced dietary salt for the prevention of cardiovascular disease
Abstract
Background
An earlier Cochrane review of dietary advice identified insufficient evidence to assess effects of reduced salt intake on mortality or cardiovascular events.
Objectives
1. To assess the long term effects of interventions aimed at reducing dietary salt on mortality and cardiovascular morbidity.
2. To investigate whether blood pressure reduction is an explanatory factor in any effect of such dietary interventions on mortality and cardiovascular outcomes.
Search strategy
The Cochrane Library (CENTRAL, Health Technology Assessment (HTA) and Database of Abstracts of Reviews of Effect (DARE)), MEDLINE, EMBASE, CINAHL and PsycInfo were searched through to October 2008. References of included studies and reviews were also checked. No language restrictions were applied.
Selection criteria
Trials fulfilled the following criteria: (1) randomised with follow up of at least six-months, (2) intervention was reduced dietary salt (restricted salt dietary intervention or advice to reduce salt intake), (3) adults, (4) mortality or cardiovascular morbidity data was available. Two reviewers independently assessed whether studies met these criteria.
Data collection and analysis
Data extraction and study validity were compiled by a single reviewer, and checked by a second. Authors were contacted where possible to obtain missing information. Events were extracted and relative risks (RRs) and 95% CIs calculated.
Main results
Seven studies (including 6,489 participants) met the inclusion criteria - three in normotensives (n=3518), two in hypertensives (n=758), one in a mixed population of normo- and hypertensives (n=1981) and one in heart failure (n=232) with end of trial follow-up of seven to 36 months and longest observational follow up (after trial end) to 12.7 yrs. Relative risks for all cause mortality in normotensives (end of trial RR 0.67, 95% CI: 0.40 to 1.12, 60 deaths; longest follow up RR 0.90, 95% CI: 0.58 to 1.40, 79 deaths) and hypertensives (end of trial RR 0.97, 95% CI: 0.83 to 1.13, 513 deaths; longest follow up RR 0.96, 95% CI; 0.83 to 1.11, 565 deaths) showed strong evidence of any effect of salt reduction. Cardiovascular morbidity in people with normal blood pressure (longest follow-up RR 0.71, 95% CI: 0.42 to 1.20, 200 events) or raised blood pressure at baseline (end of trial RR 0.84, 95% CI: 0.57 to 1.23, 93 events) also showed no strong evidence of benefit. Salt restriction increased the risk of all-cause death in those with congestive heart failure (end of trial relative risk: 2.59, 95% 1.04 to 6.44, 21 deaths). We found no information on participants health-related quality of life.
Authors' conclusions
Despite collating more event data than previous systematic reviews of randomised controlled trials (665 deaths in some 6,250 participants), there is still insufficient power to exclude clinically important effects of reduced dietary salt on mortality or cardiovascular morbidity in normotensive or hypertensive populations. Further RCT evidence is needed to confirm whether restriction of sodium is harmful for people with heart failure. Our estimates of benefits from dietary salt restriction are consistent with the predicted small effects on clinical events attributable to the small blood pressure reduction achieved.
