Healthnotes Newswire (May 31, 2007)—Reducing sodium intake is a well known first-line treatment for high blood pressure (hypertension), and the more salt is restricted, the more positive impact the change has on health. But the cardiovascular benefits of cutting down on sodium don’t stop at blood pressure reduction: new research has found that eating less salt also seems to prevent other cardiovascular diseases.
“Until now, there have been few observational studies and virtually no trial data to show the effect of sodium intake on cardiovascular diseases such as heart attack and stroke,” said Nancy R. Cook, ScD, associate professor of Medicine (Biostatistics) at Harvard Medical School and lead author of the new study.
The researchers conducted two randomized lifestyle intervention studies: the Trials of Hypertension Prevention Phase I (TOHP I), which lasted 18 months, and Phase II (TOHP II), which lasted 36 to 48 months. In both studies, participants were educated and counseled on reducing sodium in the diet. Dr. Cook and colleagues assessed the long-term effects of the dietary restrictions followed in these studies by following up with participants 10 to 15 years after the original trials.
The two studies included more than 3,000 people with slightly elevated blood pressure, or “prehypertension.” Researchers measured the incidence of cardiovascular diseases: heart attack, stroke, coronary revascularization (for example, coronary bypass surgery or angioplasty to restore blood flow), or death from cardiac causes.
People in the two trials were randomly assigned to a sodium-reduction group or to no treatment (control group). Follow-up information on illness was obtained from 77% of participants, 200 of whom reported a cardiovascular event. Risk of a cardiovascular event was 25 to 30% lower among those who restricted their salt.
“The TOHP interventions reduced sodium intake by about 25 to 35%,” said Dr. Cook. “The observed reduction in cardiovascular risk associated with this sodium decrease was substantial and provides strong support for reducing dietary sodium intake across the population to prevent cardiovascular disease.”
In the United States, current recommendations for reducing hypertension and cardiovascular disease risk call for a 50% decrease in the amount of sodium in food.
(BMJ 2007;334:885)
Jeremy Appleton, ND, CNS, is a licensed naturopathic physician, certified nutrition specialist, and published author. Dr. Appleton was the Nutrition Department Chair at the National College of Naturopathic Medicine, has served on the faculty at Bastyr University of Natural Health Sciences, and is a former Healthnotes Senior Science Editor and a founding contributor to Healthnotes Newswire. He has worked extensively in scientific and regulatory affairs in the supplement industry and is now a consultant through his company Praxis Natural Products Consulting and Wellness Services.
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