Salt Linked to Heart Woes, but Some Say the Evidence Is Shaky

Salty diets have been linked to heart woes, but how certain is the science?

ByCARRIE GANN, ABC News Medical Unit
November 10, 2011, 4:44 PM

Nov. 10, 2011— -- Uncle Sam wants you to consume less salt. The U.S. Food and Drug Administration held a day-long hearing today, discussing strategies to help Americans cut the salt from their diets, the latest assault in the crusade against sodium.

In the past few decades, the government has created guidelines, cajoled industry groups and garnered support from major medical groups such as the World Health Organization and the American Heart Association to encourage more Americans to get the salt out of their diets. Their action is stems from the medical wisdom that many know by heart: A diet high in salt raises blood pressure, which increases the risk of heart attacks, strokes and a host of other cardiovascular problems. If the food industry, restaurants and citizens cut their daily salt intake, the feds argue, the national burden of cardiovascular disease would be eased.

The FDA's goal is to get the food industry to gradually reduce the amount of salt in processed and restaurant foods, which account for 75 percent of Americans' salt intake, according to the U.S. Centers for Disease Control and Prevention.

But a number of scientists and physicians say that the case against salt is far from closed. The evidence connecting high-sodium diets with heart disease and death is flimsy, they argue, and does not warrant such sweeping changes in salt consumption.

"Other than in those patients with underlying heart or kidney failure, there is little conclusive evidence that moderate salt intake actually increases heart disease risk," said Dr. Stuart Seides, associate director of cardiology at the Washington Hospital Center.

At the forefront of the fight to save salt is the Salt Institute, an industry group representing salt manufacturers. The group is mobilizing a grassroots effort to save their seasoning, including a Facebook page and a two-minute YouTube video featuring the group's vice president of science and research, Mortin Satin, the "Salt Guru," who exhorts all salt-lovers to send in comments to the FDA's hearing, warning the feds to keep their hands off salt.

"There are biological processes, physiological processes that respond when the body gets too little salt," Satin said. "The data is not there to warrant salt reduction, and the government is willing to put the entire country into what is effectively a clinical trial."

Satin and other pro-salt supporters point to a handful of recent studies suggesting that low-sodium diets are ineffective or may even do harm. One study published Wednesday in the American Journal of Hypertension analyzed more than 160 studies of salt intake and found that a low-salt diet seemed to have a minimal effect on reducing blood pressure, and increased certain factors associated with heart disease, such as cholesterol, triglycerides and hormones associated with heart attacks.

Others take these studies with a grain of salt. Overall, they say there is overwhelming evidence that a reduction in sodium improves heart health. Dr. Norman Kaplan, a professor of internal medicine at the University of Texas Southwestern Medical Center, called it a life-and-death issue.

"More than 99 percent of the medical/scientific world simply are not wrong," Kaplan said. "Moderate salt reduction is an absolute necessity and can be attained by deletion of some of the salt added to virtually all processed food."

The advice to cut salt should be taken seriously by people who are "salt-sensitive" – those whose bodies hang on to the salt they consume, which drives up their blood pressure and creates chronic problems. About 20 percent of the population is salt-sensitive, particularly people who are overweight, African-American, or who have high blood pressure. The CDC recommends that these groups keep their daily salt consumption under 1,500 milligrams.

But for the rest of the population, some scientists say the harmful effects of salt are overblown.

"Salt intake is most dangerous for the person with left ventricular weakening, or congestive heart failure, who really need to be on a low sodium diet," said Dr. Chip Lavie, medical director of cardiac prevention at the Ochsner Clinic Foundation and Hospital in New Orleans. "However, for thin people with good heart function who have low levels of blood pressure, it probably is not so important to keep salt low."

For those groups at special risk or for others who simply want to keep their salt low, Dr. Clyde Yancy, chief of cardiology at Northwestern Memorial Hospital in Chicago, said it's exceedingly difficult, given the amount of salt that lurks in unlikely foods like bread, cookies, and ketchup.

"Nearly 60 percent of our sodium consumption is embedded in our foodstuff and is consumed passively," Yancy said. "Ideally, we would consistently have lower sodium options for most if not all food items with clear labeling. How can a message of the provision of choice in a free market society not be palatable?"

Certain food companies have proved willing to compromise on the salt content of their foods, balancing consumer demand for taste with medical and federal concerns about salt. McDonald's, Kraft, and Campbell's are among the companies that have instituted voluntary sodium reductions in some of their products.

Dr. Jay Cohn, director of the Rasmussen Center for Cardiovascular Disease Prevention at the University of Minnesota, said even eliminating the very high salt content of certain foods like soups or tomato juice would make a difference.

"Modest restriction will not harm anyone and probably will have some small benefit on the whole population," Cohn said. "It is nothing like smoking, which helps nobody and has a profound adverse effect on individuals and on the population."Until the great salt debate shakes out, experts say consumers should focus on other ways to reduce blood pressure and improve their heart health: getting regular exercise and eating a diet full of fruits and vegetables.

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