Even a small reduction in daily salt intake could mean fewer heart attacks, strokes and deaths said US researchers who estimated cutting back by as little as half a teaspoon a day could prevent 92,000 deaths and nearly 100,000 heart attacks in the US every year.
The researchers, from the University of California, San Francisco, Stanford University Medical Center and Columbia University Medical Center, suggest the benefits of cutting salt intake are on a par with reducing smoking and could save the US about 24 billion dollars in healthcare costs.
They wrote a paper on their findings that was published online in the New England Journal of Medicine on 20 January.
Figures from the American Heart Association (AHA) suggest that salt consumption in the US population has risen by 50 per cent and blood pressure by nearly the same amount since the 1970s; despite the fact evidence linking salt to high blood pressure and heart disease has been around for at least that long.
Lead author Dr Kirsten Bibbins-Domingo, UCSF associate professor of medicine and epidemiology and the co-director of the UCSF Center for Vulnerable Populations at San Francisco General Hospital, told the media that:
“A very modest decrease in the amount of salt, hardly detectable in the taste of food, can have dramatic health benefits for the US.”
“It was a surprise to see the magnitude of the impact on the population, given the small reductions in salt that we were modeling,” she added.
For the study, Bibbins-Domingo and colleagues used a computer simulation of heart disease in the US population, the Coronary Heart Disease (CHD) Policy Model, which researchers use to estimate the public health benefits that might accrue from particular changes in lifestyle and medical interventions.
With the model they estimated that if Americans were to reduce their daily salt intake by three grams a day, or about half a teaspoon (equal to about 1,200 mg of sodium), the result would be:
- 11 per cent fewer new cases of heart disease,
- 13 per cent fewer heart attacks,
- 8 per cent fewer strokes, and
- 4 per cent fewer deaths.
For African Americans the impact could be greater because they are more likely to have high blood pressure and may be more sensitive to salt. For this group there could be 16 per cent fewer new cases of heart disease and 19 per cent fewer heart attacks.
Senior author Dr Lee Goldman, executive vice president for health and biomedical sciences and dean of the faculties of health sciences and medicine at Columbia University said:
“Reducing dietary salt is one of those rare interventions that has a huge health benefit and actually saves large amounts of money.”
“At a time when so much public debate has focused on the costs of health care for the sick, here is a simple remedy, already proven to be feasible in other countries,” he added.
Co-author Dr Glenn M. Chertow, professor of medicine and chief of the Division of Nephrology at Stanford University, said:
“In addition to its independent benefits on blood pressure, reducing salt intake can enhance the effects of most anti-hypertensive (blood pressure lowering) agents and reduce complications associated with diabetes, obesity and kidney disease.”
Data from federal government sources suggest the average American man eats more than 10 grams of salt (4,000 mg of sodium) a day. This is about twice as much as that recommended by many health organizations, who suggest a daily limit of 5.8 gms of salt or 2,300 mg sodium and under 3.8 gm of salt for those over 40.
A gram of salt (sodium chloride, NaCl) contains 0.4 grams of sodium.
Bibbins-Domingo said while it’s clear they should reduce their salt intake, people find it hard to do so because most of the salt they eat comes from processed food, not from what they add themselves.
“Our study suggests that the food industry and those who regulate it could contribute substantially to the health of the nation by achieving even small reductions in the amount of salt in these processed foods.”
New York City’s Mayor Michael Bloomberg has already made sweeping changes to the City’s health regulations, cutting trans fats in eating places and making fast-food restaurants list calorie information on their menus.
In his State of the City address on Wednesday, he said NYC and other state and local municipalities are about to join a national movement seeking to reduce salt intake by 25 per cent.
Bibbins-Domingo said such regulatory efforts save healthcare costs as well as improve health:
“For every dollar spent in regulating salt, anywhere from seven to 76 healthcare dollars could be saved,” she said.
A grant from the American Heart Association Western States Affiliate and a pilot grant from the UCSF Clinical and Translational Sciences Institute helped pay for the study.
“Projected Effect of Dietary Salt Reductions on Future Cardiovascular Disease.”
Bibbins-Domingo, Kirsten, Chertow, Glenn M., Coxson, Pamela G., Moran, Andrew, Lightwood, James M., Pletcher, Mark J., Goldman, Lee.
DOI:10.1056/NEJMoa0907355
Source: UCSF.
Written by: Catharine Paddock, PhD