Cutting salt ‘cuts’ heart attack risk

People who significantly reduced the amount of salt in their diet decreased their chances of developing cardiovascular disease by 25 to 30 percent over the following 10 to 15 years, a team of researchers from Brigham and Women's Hospital and Harvard Medical School, Boston, found. Also, their risk of death from cardiovascular disease decreased by 20 percent.

Cardiovascular disease refers to the class of diseases that involve the heart and/or blood vessels.

Heart diseases alone cause 30 percent of all deaths, while other diseases of the cardiovascular system cause substantial further death and disability. Though evidence suggests that cutting back on salt or sodium in diet lowers blood pressure and subsequent levels of cardiovascular disease in the population, the results are limited and inconclusive.

Sodium is an essential nutrient and salt is the major source of sodium. Most people, however, consume more sodium than is required.
As salt affects the artery and heart health by raising blood pressure, it also makes blood vessels less flexible, thus curtaining expansion and contraction movements and toughening heart cells.

To examine the effects of reduction in dietary sodium intake on cardiovascular events, the researchers randomly picked up over 3,000 adults aged 30-54 years with pre-hypertension symptoms.

Of the total, 744 people took part in the first Trial of Hypertension Prevention (TOHP). It was completed in 1990. Remaining 2,382 participants undertook the second TOHP trail which ended in 1995.

In two randomized trails, participants slashed their salt intake by about 25 percent to 35 percent, from about 10g to around 7g.

After adjustments of age, race, and sex, risk of a cardiovascular event reduced by 25 to 30 percent.

Long term follow up reported 200 cases of adverse cardiovascular outcomes, of which 67 participants died.

Sodium reduction, previously shown to lower blood pressure, may also reduce long term risk of cardiovascular events, researchers’ concluded.

The study headed by Dr. Nancy Cook of Brigham and Women's Hospital, Boston, is published in the online version of the British Medical Journal.

"Our study provides unique evidence that sodium reduction might prevent cardiovascular disease and should dispel any residual concern that sodium reduction might be harmful," the report states.

Previous research works suggest that high salt intake causes heartburn, raised osteoporosis risk in girls, gastric cancer, hypertension and edema.

According to the Dietary Guidelines for Americans 2005, US citizens should consume less than 2,300 mg of sodium per day.

A consultant in cardiovascular medicine, Graham MacGregor at London's St. George's Hospital and chairman of the Consensus Action Group on Salt said, "This is a very important study. It shows that if people reduce their salt intake it will reduce the number of people suffering from heart attacks, strokes and heart failure. We did not have that type of evidence before.”