Are You Eating Enough Salt?

Low-sodium has been synonymous with "healthy" for decades, but recent studies call that wisdom into question.

By Beth Levine

Ah, salt! We’ve been trying to break up with you for years! Well, it turns out that we need you more than we think we do. Maybe.

New research has ignited controversy over the Centers for Disease Control (CDC) and the American Heart Association (AHA) salt intake recommendations. They are currently a daily intake of 2,300 mgs of sodium for healthy people under the age of 50, and 1,500 mgs for people over age 50, African-Americans, and people with diabetes, chronic kidney disease, and congestive heart failure. These guidelines are thought to reduce the risk of heart disease and death, since salt (sodium chloride) is an essential nutrient that plays a role in controlling the volume of water in the body, muscle contraction, and stomach health. It carries nutrients in and out of your cells. Too little, and you risk muscle cramps, dizziness, fatigue, coma, and even death. Too much, and you heighten your susceptibility to heart disease and death.

However, three recent studies—from The Institute of Medicine (IOM), part of the National Academy of Sciences, and two from the American Journal of Hypertension—have found that not getting enough salt can be harmful. Yes, you read it right. The IOM study, in particular found:

  • Reducing salt intake for the people in the recommended 1,500 mgs group may be harmful.
  • Studies on health outcomes are inconsistent and insufficient to determine whether sodium intake below 2,300 mgs increases or decreases the risk of heart disease, stroke of death from any cause. "If the data doesn’t clearly define that a recommendation is not harmful, you shouldn’t make the recommendation," says David A. McCarron, MD, FACP, Department of Nutrition, University of California–Davis, who reviewed the IOM report.
  • The report did recommend avoiding excessive intake, but did not report on what that upper limit should be.

What Experts Say About the New Studies

Dr. McCarron strongly believes that the CDC and the AHA should be adapting the information from the IOM study into their guidelines. He was also part of a 2013 study that defined the lower and upper limits of what the normal salt intake is for humans. That data was consistent with what the IOM and other recent reports indicated: that if you go below roughly 2,800 mgs a day, your risk of death from cardiovascular disease increased—independent of gender, blood pressure and age. “That data did agree that if you went above somewhere around 5,000-6,000 mgs per day, your risk also went up, but it didn’t go up in death from any cause. It only went up in certain aspects of cardiovascular disease and the rate of risk of something happening was lesser at the high end than the likelihood of an event at the low end,” explains Dr. McCarron. In other words, too little is more harmful than too much.

Dr. McCarron’s team discovered that all over the world, different populations’ general daily salt intake was around 3,400 mgs. “The data encompassed almost 75,000 people, five decades of observations and 45 different countries in all their unique and changing culinary styles, and the number is the same,” he says. He explains that the brain regulates the amount of any essential nutrients that the body takes in. It uses what it needs and excretes the extra, if it is not excessive. (And remember, the IOM is not reporting on what is excessive.) Dr. McCarron added, “We are endowed with the ability to get rid of excessive sodium chloride to a point. We have no way of manufacturing it.”

What the CDC Says About Salt

But before you start mainlining potato chips, know this: So far the CDC, which commissioned the IOM report, and the AHA, are not changing their guidelines. And don’t forget that the IOM did not establish what the upper limit of salt intake should be. Meaning: It remains mum on how much sodium is too much.

“While the American Heart Association commends the IOM for taking on the challenging topic of sodium consumption, we disagree with key conclusions,” says the association’s CEO Nancy Brown. “The report is missing a critical component – a comprehensive review of well-established evidence which links too much sodium to high blood pressure and heart disease.”

The CDC declined to comment directly on the study results, but Janelle Gunn, RD, MPH, CDC Division for Heart Disease and Stroke Prevention, does say, “The Centers for Disease Control and Prevention follows the United States Dietary Guidelines for Americans, which are the cornerstone of Federal nutrition policy, education, outreach, and food assistance programs.” Gunn does add, however, that “the Dietary Guidelines for Americans (DGAs) are currently being reassessed and [updated] DGAs are expected in 2015.” She does not say if the findings of the IOM and American Journal of Hypertension studies would be reflected.

Whose Advice Should You Follow?

So, what’s a consumer supposed to do with this conflicting information? Gunn says, "The majority of evidence shows that higher sodium intake is associated with higher blood pressure - a major risk factor for heart disease and stroke, the first and fourth leading causes of death, respectively in the United States. The Dietary Guidelines for Americans, including those for sodium intake, are based on the most available, current and relevant scientific evidence. Because most Americans exceed the general recommended limits of sodium intake, the DGAs advise people to lower sodium intake and to follow an overall heart-healthy diet, such as the DASH dietary pattern, that emphasizes fruits, vegetables, and whole grains to reduce blood pressure and improve cardiovascular health. CDC encourages those under medical care to check with their health care provider before starting a diet that severely restricts sodium intake."

Dr. McCarron disagrees: "The IOM report is the most recent assessment of the data, and it said the guidelines are not supported by the science. The intake data says a vast majority of Americans currently ingest the correct amount. It is only excessive because the government says it is; the IOM did not define excessive, thus the DGA recommendations are the ones out of synch." He does agree, however, with Gunn’s recommendation to for people to speak with their physicians. The best thing you can do is arm yourself with relevant, current information, and bring it to your health care provider for discussion on the best way forward for your particular health issues.

Comments

it also causes you to have a big saggy chin called a Goitre that is caused from low iodine.Worldwide, over 90.54% cases of goitre are caused by iodine deficiency...which can lead to hypothyroidism or hyperthyroidism...

iphatcoolcat@hotmail.com on 2014-05-08 08:06:13

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