U.S.- wide salt reduction could prevent deaths : study
The United States could prevent up to half a million deaths over the next decade if Americans cut their salt intake to within national guidelines, according to a new study.
That finding - which comes the week New York City announced success toward its goals of cutting salt levels by one-quarter by 2014 - is based on computer simulations using data from various studies on the effects of extra sodium on blood pressure and heart risks.
The Institute of Medicine recommends most healthy people get 1,500 milligrams (mg) of sodium per day, with an upper limit of 2,300 mg. But the average American eats more like 3,600 mg each day, largely through processed food.
“Reducing sodium intake is important for everyone, not just a small subset of people who are salt sensitive,” said Pamela Coxson, the study’s lead author from the University of California, San Francisco.
Although the health effects of a salt cutback may be small for the average person, she said, the results show they add up when projected across millions of Americans.
Still, one blood pressure researcher not involved in the new study said the models don’t reflect the full picture of health consequences tied to too little or too much salt.
Too much sodium can raise a person’s risk for high blood pressure, heart disease, stroke and other vascular diseases, and government estimates show 90 percent of Americans exceed their recommended daily allotment.
Now, new research shows that by reducing sodium intake to recommended levels or beyond could prevent hundreds of thousands of deaths.
“No matter how we look at it, the story is the same - there will be huge benefits in reducing sodium,” study author Dr. Pam Coxson, mathematician UC San Francisco who performed one of three analyses included in the study, told UCSF News.
Americans on average consume about 3,600 milligrams of sodium each day, mostly from table salt (or sodium chloride), which is found primarily in processed foods. The top six sources of sodium in the American diet according to the American Heart Association, or “The Salty Six” are bread and rolls, cold cuts and cured meats, pizza, poultry, soup and sandwiches. The government recommends a limit of 2,300 milligrams per day of sodium and 1,500 milligrams for those 51 and older while the AHA recommends 1,500 milligrams each day.
The Centers for Disease Control and Prevention said that excess sodium is one of the factors that can raise the risk for heart disease. For the month of February, National Heart Month, the CDC offers 28 tips for a healthier heart.
Coxson and her colleagues ran three salt-reduction scenarios through models that predicted how a lower-sodium diet would impact a person’s risk of having high blood pressure or dying of cardiovascular disease.
The most realistic scenario was a gradual decline in Americans’ average sodium intake over ten years to about 2,200 mg per day. That goal would be “optimistic but potentially achievable,” the researchers wrote in the journal Hypertension.
Based on their calculations - and taking into account uncertainties about sodium’s direct effect on the heart - Coxson and her colleagues calculated 280,000 to 500,000 fewer Americans would die over the next decade as a result of that reduction.
We should recognize that the national conversation about salt and sodium should not be just about salty taste and sodium reduction, but about flavor in our foods in general. For much of the 20th century, our national food and agricultural focus has been on quantity and value - and quality often as a function of consistency, appearance, safety, convenience, and shelf life. If natural flavor sometimes suffered, there was always fat (often saturated fats and trans fats), sugar, and salt to take up the slack - all high-impact, low-cost flavor enhancers that most people love. But at a time when we have “over-delivered” on the promise of affordable calories, and both salt and sugar (and all refined carbohydrates) are turning out to have serious negative health consequences, we need to refocus our attention on enhancing natural flavors. As a practical matter, this means growing more flavorful tomatoes at the same time we try to reduce the sodium in tomato soup.
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Too many of us have the habit of reaching for the salt shaker as soon as our plates are put in front of us. Try taking the salt shaker off the table and making it available “upon request only.” Always, always taste your food before you salt: Maybe you don’t need the extra sodium. And in the kitchen, add salt late in the cooking process. Foods release their flavors (and salt, in the case of salted ingredients) during the cooking process, and “palate fatigue” on the part of the cook can cause over-salting if this is undertaken too early.
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Collectively, because we eat so much of it, bread is one of the largest contributors of sodium to our diets. Even whole grain bread, while a healthier choice than white, can contain considerable sodium. But only part of the sodium in bread is for taste: Much of it is used to help the bread-making process and preserve the final results. You can skip that extra salt when you use these marvelous whole grains by themselves. Try a Mediterranean-inspired whole grain salad with chopped vegetables, nuts, and legumes, perhaps a small amount of cheese, herbs and spices, and healthy oils and vinegar or citrus. You can enjoy many of the same flavors you love in a sandwich, but in a delicious new form that has much less sodium. For breakfast, cook up steel cut oats, farro, or other intact whole grains with a generous amount of fresh or dried fruit, and you can skip the toast (and the extra sodium).
A more dramatic and immediate decline to 1,500 mg of salt per day across the U.S. population could prevent up to 1.2 million deaths, largely from heart disease or stroke, the researchers calculated. But that isn’t very realistic, policy-wise.
“The gradual reduction is something that many countries around the world are working on in various ways,” Coxson told Reuters Health.
For example, she said, some countries have worked with bakers to cut back on sodium in bread, and others have focused on meat and canned goods.
“The big majority of our intake of sodium is coming from those types of processed foods,” Coxson said.
“The individual at home with their salt shaker only controls maybe 20 to 25 percent of their intake.”
TOO LITTLE SODIUM?
Dr. Michael Alderman from the Albert Einstein College of Medicine in Bronx, New York, said the researchers’ calculations are missing data on how too little sodium can also raise heart risks, through its effect on blood fats and insulin.
“They begin with the hypothesis that lowering sodium intake, because it will lower blood pressure - and nobody debates that - will inevitably translate into a reduction in cardiovascular events,” he told Reuters Health.
But in reality, he said, “The net effect of these conflicting consequences of reducing sodium will be the health effect.”
Alderman said there’s no evidence eating less than 2,000 mg of sodium per day is beneficial for the average person. “Like every other essential nutrient that I know of, too little is not good for you, and too much is not good for you,” he said.
For people who do want to cut back on their sodium, Coxson said diet changes are possible despite the influence of the country’s salty, processed food environment.
“The best thing would be if we could all shift our consumption a little more toward fresh fruits and vegetables, and away from processed foods,” she said.
SOURCE: Hypertension, online February 11, 2013
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Mortality Benefits From US Population-wide Reduction in Sodium Consumption
Computer simulations have been used to estimate the mortality benefits from population-wide reductions in dietary sodium, although comparisons of these estimates have not been rigorously evaluated. We used 3 different approaches to model the effect of sodium reduction in the US population over the next 10 years, incorporating evidence for direct effects on cardiovascular disease mortality (method 1), indirect effects mediated by blood pressure changes as observed in randomized controlled trials of antihypertension medications (method 2), or epidemiological studies (method 3).The 3 different modeling approaches were used to model the same scenarios: scenario A, gradual uniform reduction totaling 40% over 10 years; scenario B, instantaneous 40% reduction in sodium consumption sustained for 10 years to achieve a population-wide mean of 2200 mg/d; and scenario C, instantaneous reduction to 1500 mg sodium per day sustained for 10 years. All 3 methods consistently show a substantial health benefit for reductions in dietary sodium under each of the 3 scenarios tested. A gradual reduction in dietary sodium over the next decade (scenario A) as might be achieved with a range of proposed public health interventions would yield considerable health benefits over the next decade, with mean effects across the 3 models ranging from 280 000 to 500 000 deaths averted. Projections of instantaneous reductions illustrate the maximum benefits that could be achieved (0.7–1.2 million deaths averted in 10 years). Under 3 different modeling assumptions, the projected health benefits from reductions in dietary sodium are substantial.
Pamela G. Coxson,
Nancy R. Cook,
Michel Joffres,
Yuling Hong,
Diane Orenstein,
Steven M. Schmidt,
Kirsten Bibbins-Domingo
From the Department of Medicine, University of California San Francisco (UCSF), San Francisco, CA (P.G.C., K.B-D.); Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA (K.B.-D.); Division of Preventive Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA (N.R.C.); Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada (M.J.); and Division for Heart Disease and Stroke Prevention, Centers for Disease Control and Prevention, Atlanta, GA (Y.H., D.O., S.M.C.).
Correspondence to Pamela G. Coxson, UCSF-SFGH, Box No. 1364, San Francisco, CA 94143. E-mail .(JavaScript must be enabled to view this email address)