Arun Chockalingam， MS， PhD， FACC
世界高血压联盟秘书长
加拿大温哥华Simon Fraser大学

    Salt (sodium chloride) plays a ma- jor role in the regulation of blood pressure (BP). Influence of dietary salt on high blood pressure is well documented even 2500 year ago by the Chinese Yellow Emperor Huang Ti. When too much salt is consumed there is a corresponding retention of water in the body and the blood pressure rises. Epidemiological studies have shown positive correlation between salt intake and blood pressure in different populations. While the majority of the population worldwide are ‘salt sensitive’， some are ‘salt resistive’. Those who are lucky to be salt resistive never experienced an increase in blood pressure with increasing dietary salt consumption.  However， these people are very rare.

The relation between salt intake and blood pressure and corresponding stroke mortality in the population has been well demonstrated in the literature. Likewise when the dietary salt intake is lowered there is proportional decline in blood pressure in the population. Change in blood pressure is significantly higher in hypertensive population compared to normotensive controls. 

    The epidemiologic evidences point to harmful effects of salt beyond hypertension—resulting in increased left ventricular mass and stomach cancer. The Finnish experience clearly demonstrates that population-wide reduction of dietary salt leads to population-wide reductions in BP and parallel reductions in deaths from stroke and heart disease.
Human consumption of dietary salt is significantly more than what is required. Since high blood pressure is the main risk factor for all (cardio-， cerebro- and reno-) vascular diseases we believe that salt leads to harmful public health. 

    In most western diets， over 75% of salt we consume comes from processed or manufactured food.  Whereas， in China， people use little processed food and much of it comes from cooking or added at the table. Therefore， in the Western society it is essential to work with food manufacturers to reduce dietary salt content and educate the public to avoid or minimize salt on the table or in cooking. In China， it is estimated that people consume as much as 15～20 grams of salt (or 6000～8000 mg of sodium) per day per person. It is also known that people in northern China consume much more salt in their diet than the southern Chinese people. Correspondingly， higher prevalence of hypertension and cerebrovascular stroke is seen in northern China compared to the southern population.

    Economic analysis shows by reducing daily dietary sodium consumption to less than a tea spoon or 2000 mg through public policy， at least 22% of vascular related deaths can be averted. This could mean as much as 150 000 deaths per year could be avoided in China alone. Cost to implement low salt diet is less than 1 RMB per person per year.
The World Hypertension League (WHL) is aiming to work with its 85 member countries to promote awareness of salt and hypertension during the World Hypertension Day， May 17  2009.  The theme is:“Salt and Hypertension -Two silent killers”. The awareness programs in each of the WHL countries will include public education campaigns， working with physicians to advise their patients to reduce salt consumption， working with policy makers to promote healthy public policy as well as working with global food manufactures to reduce the dietary sodium content in the processed foods. While we recommend a decrease in dietary sodium content we also recommend， at the same time， to increase dietary potassium content. While salt (sodium) is bad for your health， potassium is good for health. Potassium is available in plenty in fresh fruits such as banana and leafy vegetables such as broccoli and cabbage.

    In a country like China，where much of the salt comes during cooking， an emphasis on education at the family level is important. Also we need to educate the restaurant owners to produce food with less salt. Although our taste buds are accustomed to salt， because of lifelong dietary habits， it is possible to get used to lower salt.
Let us reduce salt in our diet， enjoy the freshness of the food and live healthy for a long time!
 

  盐和高血压

  盐（氯化钠）在血压调节中发挥重要作用。早在2500年前的《黄帝内经》中就有食盐导致高血压的记载。当盐摄入过多时，体内水分潴留，导致血压升高。流行病学研究表明，在不同的人群中，盐摄入和血压之间均存在正相关关系。大部分人属于“盐敏感”型，一小部分人属于“盐抵抗”型。幸运的是，“盐抵抗”者即使摄入过多的盐也不会患上高血压，但是属于该型的人仍为极少数。

    文献中已经有关于盐摄入与血压及其相应卒中死亡率关系的详细记载。当摄盐减少时，血压会相应下降，高血压患者的血压变化要比血压正常者明显。

    流行病学研究还显示，盐摄入过多除了引起高血压以外，还可以导致左室体积增大和胃癌。芬兰的研究表明，整个人群的盐摄入量减少以后，人群血压会相应降低，同时卒中和心脏病的死亡率降低。

    人们摄入的盐实际上已经远远超过了对盐的需求。因为高血压是所有血管疾病（心、脑、肾）的主要危险因素，所以我们认为盐摄入过多有害公众健康。

    在大多数西方饮食中，75%以上的盐来源于加工或人造食品。在中国，人们很少食用加工食品，盐主要来源于烹饪或调味。因此，在西方国家，与食品加工商密切合作减少盐的用量以及教育公众在烹饪或调味时不吃盐或少吃盐十分重要。在中国，估计每人每天要食用15～20克盐（相当于6000～8000 mg钠），北方人比南方人食用的盐更多。相应地，北方人比南方人更容易患高血压和脑卒中。

    经济分析显示，通过公众健康教育将盐摄入量控制在少于1茶匙或2000 mg以下时，能够至少减少22%的血管性死亡。这意味着，单在中国平均每年就可以减少150 000例死亡，而实施低盐饮食的费用低于1元/人年。

    2009年5月17日是世界高血压日，届时世界高血压联盟（WHL）及其85个成员国将普及盐摄入和高血压关系的相关知识，活动主题为“盐和高血压——两个无声的杀手”。WHL的每个成员国均应当开展全民健康教育，同医生一起劝告患者减少盐的摄入，与政府官员合作促进公众健康教育的实施，同时与全球的食品制造商协商以减少加工食品中盐的含量。我们在推荐限制钠摄入的同时，也提倡增加钾的摄入。食盐（钠）对我们的健康有害，但是钾对健康是有益的。香蕉等新鲜水果和甘蓝、卷心菜等多叶蔬菜中均富含钾。

    像中国这样的国家，盐摄入主要来源于烹饪，所以强调家庭水平的教育是很重要的。同时应该教育餐饮从业者减少盐的用量。虽然长久以来的饮食习惯使得我们的味蕾已经对盐产生了适应，但是让它适应低盐饮食也是完全可能的。

让我们携手减少盐的摄入，享受新鲜的食物和健康的人生。