人们通常认为，过度减少盐的摄入对身体健康没有益处，甚至会增加一些疾病的发病率，缩短寿命。但一项发表在《心血管病进展》上的最新研究反驳了此看法。
赫尔辛基大学Heikki Karppanen博士和Kuopio大学Eero Mervaala博士表示，在过去30年里芬兰人的盐摄入量平均降低了30％-35％，与之相应，65岁以下人群中风和冠心病的死亡率也大幅度下降了75％-80％。在此期间，芬兰人的预期寿命延长了6-7年。
出现这种令人欢欣的改变最主要是由于人们的平均血压下降了10 mmHg，，平均胆固醇水平也有明显下降，从而降低了心脏病的发病率，但药物在这方面仅起到10%的作用。
美国食盐协会的销售数据显示，在80年代中期到90年代末的15年间，美国的盐摄入量增加了五成之多。该研究指出，高血压的患病率曾一度出现下降趋势，但随着盐摄入量的增加而再次上升。
研究中最有趣的是发现了盐摄入与肥胖之间的紧密关系。研究指出，增多钠盐摄入势必会引起口渴，伴随而来的是饮料的摄入量增加，从而使美国在该时期的卡路里摄入量出现明显的净增加。在美国1977-2001年间，从加糖饮料中获得的能量平均增加了135%，与此同时，从牛奶中获得的能量却减少了38%。这样每人每天的能量摄入量净增加了278千焦。美国心脏协会估计，为了消耗这每天增加的278千焦卡路里，避免肥胖症或使肥胖加剧，每个美国人每天应比1977年多步行或吸尘1小时10分钟。不幸的是，人们并没有这样做。与1976-1980年相比， 1988-1994年间患肥胖症的男性增加了61%，女性则增加了52%，而1999-2002年间患肥胖症的男性增加了120%，女性则增加了99%。盐的摄入增多，也会增加口渴，从而增加了高能量饮料的摄入，这显然促使了美国肥胖症患病率升高。
值得注意的是，1983年前美国的盐摄入量没有变化，甚至出现持续的下降趋势。此段时期肥胖症的患病率也相应较低，而且在60年代早期到80年代早期没有太大的变化。研究显示，在现在的工业化社会，肥胖问题一直是悬而未决的难题，全面减少盐的摄入可以减少高能量饮料的摄入，这是减少肥胖症的一种强而有效的方法。
研究员认为，现在有确证证明全面减少盐的摄入对身体健康有益，而且还能减少肥胖。在芬兰的长期人口调查结果显示，大量减少盐的摄入并没有副作用。Karppanen教授认为，各企业反复发出全面减少盐摄入有损身体健康的警告，这种做法是不正当的，而且是不道德的。
http://www.eurekalert.org/pub_releases/2006-11/uoh-sii110106.php
Salt intake is strongly associated with obesity
Comprehensive reduction in salt intake would be a powerful means against obesity, claims new study
A study published in the journal "Progress in Cardiovascular Diseases" refutes the frequently repeated claims that a comprehensive salt reduction would not produce any overall health benefits, or would even increase diseases and shorten the life-span.
Professors, Dr. Heikki Karppanen of the University of Helsinki and Dr. Eero Mervaala of the University of Kuopio report that an average 30-35 % reduction in salt intake during 30 years in Finland was associated with a dramatic 75 % to 80 % decrease in both stroke and coronary heart disease mortality in the population under 65 years. During the same period the life expectancy of both male and female Finns increased by 6 to 7 years.
The most powerful explaining factor for the favorable changes was the more than 10 mmHg ("point") decrease in the average blood pressure of the population. A marked decrease in the average cholesterol levels of the population also remarkably contributed to the decrease of heart diseases. The extensive use of drugs contributed less than 10 % of the observed decreases in blood pressure, cholesterol, and cardiovascular diseases.
"To our surprise, the sales figures of the American Salt Institute divulged that salt intake increased more than 50 % in USA during 15 years from mid-1980s to the late 1990s", says Professor Karppanen. The study reports that the prevalence of high blood pressure, which had long shown a decreasing trend, turned to a marked increase concomitantly with the increase in salt intake.
Perhaps the most interesting finding of the study is the close link between salt intake and obesity. The study reports that increasing intakes of sodium (salt) obligatorily produce a progressive increase in thirst. The progressive increase in the average intake of salt explains the observed concomitant increase in the intake of beverages which, in turn, has caused a marked net increase in the intake of calories during the same period in the United States.
Between 1977 and 2001, energy intake from sweetened beverages increased on the average by 135 % in the United States. During the same period, the energy intake from milk was reduced by 38 %. The net effect on energy intake was a 278 kcal increase per person a day. The American Heart Association has estimated that, to burn the average increase of 278 kcal a day and avoid the development or worsening of obesity, each American should now walk or vacuum 1 hour 10 minutes more every day than in 1977. Unfortunately, this has not been the case.
In a decade from 1976-1980 to 1988-1994 the prevalence of obesity increased 61 % among men and 52 % among women. During 1999 to 2002, the prevalence of obesity was 120 % higher among men and 99 % higher among women as compared with the 1976 to 1980 figures. The increased intake of salt, through induction of thirst with increased intake of high-energy beverages has obviously remarkably contributed to the increase of obesity in the United States.
It is noteworthy that, until 1983 the use of salt did not change or even showed a continuous decreasing trend in the United States. The prevalence of obesity was relatively low and remained essentially unchanged from early 1960s to early 1980s. The study suggests that a comprehensive reduction in salt intake, which would reduce the intake of high-energy beverages, would be a potentially powerful means in the so far failed attempts to combat obesity in industrialized societies.
The authors conclude that there now is conclusive population-wide evidence, which indicates powerful beneficial health effects of comprehensive salt reduction. Decrease of obesity is now added to the previous list of recognized benefits. The population-wide long-term experience from Finland indicates that a remarkable decrease in the salt intake has not caused any adverse effects. Professor Karppanen states that "the repeated warnings of various industries on possible harmful effects of comprehensive salt reduction are unjustified and even unethical".
编辑：蓝色幻想
