Salt is commonly viewed as the enemy of a healthy diet. However, liberal use of the salt shaker might actually be more of a cure than a curse when it comes to human health, according to new research.
The study, published Tuesday in the Journal of the American Medical Association (JAMA), followed health trends in 3,681 individuals over a median of almost 8 years, and found that a higher sodium intake was actually associated with a lower incidence of cardiovascular disease (CVD), and that the amount of salt consumed had no correlation with hypertension.
Participants were divided into three groups based on their salt consumption: low, medium or high. Results showed a higher rate of deaths from cardiovascular disease (4.1 percent) among the low-salt population than among the high-salt group, only 1.9 percent of whom died of cardiovascular disease.
Hypertension rates were found to be the same between people in the high-salt category and those in the low, suggesting that salt intake does not increase the risk of high blood pressure.
“We started this study more than 25 years ago, and in all our studies, it was almost impossible to find an association between blood-pressure and 24-hour sodium excretion,” said Dr. Jan A. Staessen, professor of medicine at the University of Leuven in Belgium and one of the study’s authors, in a news@JAMA interview.
This research, which suggests that salt may not be detrimental to health after all, and might even contribute to a decrease in CVD-related mortality, runs counter to the government’s current nutritional policy, which has been pushing for a reduction of salt in the American diet on the theory that it’s dangerous in large doses.
Indeed, the most recent Dietary Guidelines issued by the Food and Drug Administration recommend a daily intake of 2,300 mg of sodium for healthy individuals, a reduction of almost 1/3 from the 3,400 mg Americans now consume, according to the Mayo Clinic.
And the new U.S. Department of Agriculture rules for the National School Lunch Program, set to go into effect in 2012, limit the amount of sodium allowed in schools lunches to around 700 mg.
In light of this latest study, as well as previous research, the industry’s Salt Institute says it’s time for the government to change course.
“This study confirms previous research that reductions in sodium lead to an increased risk of disease and death,” said Lori Roman, president of the Institute, in a statement. “Therefore, we call on government agencies to stop their population-wide sodium reduction agenda and amend the Dietary Guidelines on sodium,” Roman said.
The previous studies Roman refers to include one indicating that low sodium intake has a detrimental effect on the elderly, one that found babies with low birth weight to also have low amounts of sodium in their blood, and a 2010 study from Harvard showing no connection between hypertension rates and sodium consumption.
The Salt Institute cautions that FDA should not wait until the next revision of the Dietary Guidelines in 2020 to change its sodium recommendations, because doing so would put people at risk.
“We don’t feel like we can wait another 10 years for the next set of dietary guidelines. This train is going down the track, and we believe this study is a can’t-miss red light saying whoa, let’s put the brakes on. Let’s at least look at all the available evidence, and let’s do some more research before we actually harm the U.S. population,” said Mark O’Keefe, the Institute’s communication director, in an interview with Food Safety News.
But others say that salt-lovers shouldn’t salt their chicken before more research hatches.
“They took one urine sample at one point of time and took a hugely broad brush and made conclusions for the world,” said Dr. Randall Zusman of Massachussettes General Hospital Heart Center in an interview with CommonHealth. Zusman says that people’s diets vary from day to day, and that the average of 5 urine samples collected per person for this study might not reflect their normal salt intake patterns.
In addition, observational studies such as this show only a correlation, but cannot prove cause and effect between lower salt consumption and heart disease, Dr. Laura Svetkey, director of the Duke Hypertension Center, told the Boston Globe.
Zusman says the study could be dangerous if seen as a blanket go-ahead to start popping pickles. When he recommends that patients decrease their salt intake, he says, it’s not just to decrease their blood pressure, but to help them avoid negating positive effects of medication.
And for the healthy population, traditionally salty foods are also often fatty or loaded with carbohydrates, making them an unhealthy option regardless of sodium content, he adds.
O’Keefe disagrees. He says that salt actually contributes to making healthy foods such as broccoli more flavorful and therefore more appealing, particularly to kids.
So now, the question: to take the table salt off the table, or leave it?
Staessen says his study should be treated as a jumping-off point for further research on the effects of sodium on cardiovascular disease.
“What one needs is a long-term interventional study to look at cardiovascular complications,” he says.
And Zusman sees this study as promoting the debate on the effects of salt, rather than ending it.
“The most important thing is that [the authors] are hypothesis-generating. They’re suggesting that perhaps we don’t understand as much as we thought we did about salt, cardiovascular disease and blood pressure,” he says.