A national program to reduce dietary salt could prevent tens of thousands of heart attacks, strokes and deaths and trim as much as $24 billion from the U.S. health-care tab, according to a study published Wednesday in the New England Journal of Medicine.

    The study, a computer simulation, suggests the impact would be similar to prevention strategies such as quitting smoking, lowering cholesterol or modest weight-loss.

    But significant cuts in salt from the diet could be challenging for individuals without action from food manufacturers. Some 75% of dietary salt intake comes from processed foods, according to the researchers.

    Their findings add to a growing body of research suggesting that lowering dietary salt could be an effective weapon against high blood pressure and cardiovascular disease. 'The time is right now to consider efforts to . . . achieve population wide reduction in salt' intake, says Kirsten Bibbins-Domingo, first author of the study and an associate professor of medicine and epidemiology at the University of California, San Francisco.

    Morton Satin, technical director of the Salt Institute, a nonprofit group of salt producers, says few data exist linking salt intake and disease. He is skeptical that reducing salt will yield important health benefits.

    Americans consume far more than the recommended daily salt intake. The average adult male consumes more than 10 grams of salt a day, according to the U.S. National Health and Nutrition Examination Survey. On Wednesday, the American Heart Association published new guidelines calling for all Americans to reduce their daily intake of sodium -- a key component of salt -- to 1,500 milligrams, equivalent to 3.8 grams of salt. Previously, that was the recommended limit for higher risk individuals; the regular limit had been 2,300 milligrams of sodium, or 5.8 grams of salt.

    In the computer simulation, which included data from the U.S. Census, the Centers for Disease Control and Prevention and other national studies, Dr. Bibbins-Domingo and her colleagues estimated the effect of lowering salt in the daily American diet by a small amount -- up to three grams a day -- in adults age 35 and older.

    Based on other research, they assumed a three-gram reduction in salt would lower systolic blood pressure by 3.6 to 5.6 millimeters of mercury; a one-gram reduction would reduce the level by 1.2 to 1.9 millimeters. （Systolic is the higher number in a blood-pressure reading. People whose level is 140/90 or more are considered to have high blood pressure.） Such modest blood-pressure reductions are associated, in other studies, with significant lowering of risk of death, heart attack and stroke.

    In the current study, researchers found that lowering salt intake by three grams a day would cut new cases of heart disease annually by a third -- an estimated 60,000 to 120,000 cases per year -- heart attacks by 54,000 to 99,000 cases and strokes by 32,000 to 66,000 cases. It would reduce about 100,000 deaths a year in the U.S.

    據《新英格蘭醫學雜志》（New England Journal of Medicine）1月20日刊登的一篇研究稱，一項旨在降低飲食中鹽攝入量的國家項目將減少數以萬計的心臟病發作、中風和死亡病例，并使美國的國民醫療費用降低240億美元。

    這項運用了電腦模擬的研究顯示，這種影響類似于戒煙、降低膽固醇或適度減肥等預防性策略的影響。

    但是，如果食品生產企業不行動起來，僅靠個人很難做到顯著降低飲食中的鹽攝入量。研究人員稱，飲食中約75%的鹽攝入量來自于加工食品。

    有越來越多的研究都表明降低飲食中的鹽攝入量是對抗高血壓和心血管疾病的有效武器，這項成果進一步充實了這些研究。"在全社會范圍內展開降低鹽攝入量的行動……現在正是時候",這項研究的第一作者、加利福尼亞大學舊金山分校（University of California）的醫學與流行病學副教授柯爾斯滕？比賓斯-多明戈（Kirsten Bibbins-Domingo）說。

    美國鹽業協會（Salt Institute,一家由鹽類生產商組成的非贏利組織）的技術總監莫頓？薩坦（Morton Satin）稱，幾乎沒有數據顯示鹽攝入量與疾病之間存在聯系。他對降低鹽攝入量明顯有益于健康表示懷疑。

    美國人的每日鹽攝入量遠遠高于建議每日鹽攝入量。據《美國國民健康與營養調查》（U.S. National Health and Nutrition Examination Survey.）顯示，一名普通美國成年男性一天攝入的鹽超過10克。1月20日，美國心臟協會（American Heart Association）公布了新的指引，呼吁所有美國人將每日的鈉攝入量──鈉是鹽的主要成份──降至1,500毫克，相當于3.8克鹽。以前，這是高風險人群的建議攝入限量；常規攝入限量原本為2,300毫克鈉，或5.8毫克鹽。

    在包括來自美國人口普查、疾病控制與預防中心和其它全國性研究的數據的電腦模擬中，比賓斯-多明戈博士和她的同事們估計了小幅降低美國人每日鹽攝入量──每日最高降低3毫克──對35歲及35歲以上成人的影響。

    根據其它研究，他們假設減少3毫克的鹽攝入量將降低3.6至5.6毫米汞柱的收縮壓；減少1毫克的鹽攝入量將降低1.2至1.9毫米汞柱的收縮壓。（收縮壓是血壓讀數的較高值。血壓水平為140/90或更高的人被認為患有高血壓。）其它研究發現，這種適度的血壓降低與死亡、心臟病發作和中風風險的顯著降低相關。

    在目前的研究中，研究人員發現，每天降低3克鹽攝入量，將使每年的新增心臟病病例降低三分之一，估計可減少60,000宗至120,000宗病例；使心臟病發作病例減少54,000至99,000宗；使中風病例減少32,000至66,000宗。這一做法還將使美國每年減少約100,000宗死亡病例。