Salt: Is it Really Bad for You?

 

We’re all used to hearing it: salt is bad for you. For decades, we’ve constantly been told that limiting salt intake is the key to reducing blood pressure, cardiovascular disease and countless other medical issues. According to the U.S. government, the American diet is exposing us to dangerous sodium levels that contribute to the deaths of tens of thousands of people a year. The problem with these claims, however?

They aren’t actually backed by scientific evidence.

 

Current dietary recommendations

Current U.S. Dietary Guidelines recommend limiting sodium intake to 2.3 g/day (that's about a teaspoon) for healthy individuals under the age of 50, while adults over age 50 as well as all African-Americans, and anyone with HBP, diabetes or chronic kidney disease is advised to limit sodium intake to 1.5 g/day.

If these measurements are correct, Americans are indeed endangering themselves, as the typical sodium ingestion rate is about 3.5 g/day.

However, if the skeptics are right, most Americans are fine. In fact, many scientists believe a typical healthy person can consume 6 g/day without significantly raising health risks.

Of course, individuals with high blood pressure are at an increased risk for multiple diseases (ie, coronary artery disease, heart failure, stroke, and renal disease). However, it is not scientifically known whether or not a high dietary salt intake can directly lead to these diseases.

Individual salt sensitivity

Part of the problem is that individuals vary in how they respond to salt. That is because "the human kidney is made, by design, to vary the accretion of salt based on the amount you take in," explains Michael Alderman, an epidemiologist at the Albert Einstein College of Medicine and former president of the International Society of Hypertension.

The National Heart, Lung, and Blood Institute convened a Working Group (WG) in 2014 to discuss this new emerging scientific area in hypertension research. The WG explained that salt sensitivity is a common biological phenomenon in human populations. Both genetic and environmental factors determine an individual’s salt sensitivity. In fact, genetic factors may account for 27% to 42% of the variation in blood pressure salt sensitivity.

Not the results you expected

 

 

Recent studies have called for the consideration of the intakes of other minerals such as potassium, magnesium and calcium in addition to just sodium in relations to BP regulation. A study published April of this year analyzed the data of 2,632 subjects’ ages 30-64 years across 16 years to address the question of the long-term effect of dietary sodium in particular on systolic (SBP) and diastolic blood pressures (DBP).

Surprisingly, results showed those with the lowest SBP and DBP levels (129.5 and 75.6 mm Hg, respectively) were those with higher intakes of both sodium and potassium while those with the highest SBP and DBP levels (135.4 and 79.0 mm Hg, respectively) were those with lower intakes of both.

Sound opposing to the government claims? That’s because it is.  

 

Another study in the 2006 American Journal of Medicine compared the reported daily sodium intakes of 78 million Americans to their risk of dying from heart disease over the course of 14 years. It found that the more sodium people ate, the less likely they were to die from heart disease.

Similarly, in 2007 the European Journal of Epidemiology published a study that followed 1,500 older people for five years and found no association between urinary sodium levels and the risk of coronary vascular disease or death. Seeing a trend here?

It appears that with every study that suggests that salt is unhealthy, comes another that expresses just the opposite.

 

In fact, a meta-analysis of seven studies involving a total of 6,250 in the American Journal of Hypertension found no strong evidence that cutting salt intake reduces the risk for heart attacks, strokes or death in people with normal or high blood pressure.

Claims that cutting down salt intake will protect you from such diseases are not evidence; they are conjecture.

If there’s anything these studies show it’s that we need to do more research before mindlessly agreeing with nutrition-based claims.

It turns out salt might not be as bad as you thought.

 

Resources:

Moore, Lynn L., Martha R. Singer, and M. Loring Bradlee. "Low Sodium Intakes Are Not Associated with Lower Blood Pressure Levels among Framingham Offspring Study Adults." The FASEB Journal. N.p., 01 Apr. 2017. Web. 28 May 2017.

Moyer, Melinda Wenner. "It's Time to End the War on Salt." Scientific American. N.p., 08 July 2011. Web. 28 May 2017.

Oh, Young S., Lawrence J. Appel, Zorina S. Galis, David A. Hafler, Jiang He, Amanda L. Hernandez, Bina Joe, S. Ananth Karumanchi, Christine Maric-Bilkan, David Mattson, Nehal N. Mehta, Gwendolyn Randolph, Michael Ryan, Kathryn Sandberg, Jens Titze, Eser Tolunay, Glenn M. Toney, and David G. Harrison. "National Heart, Lung, and Blood Institute Working Group Report on Salt in Human Health and Sickness." Hypertension. American Heart Association, Inc., 01 Aug. 2016. Web. 28 May 2017.

Whoriskey, Peter. "Is the American Diet Too Salty? Scientists Challenge the Longstanding Government Warning." The Washington Post. WP Company, 06 Apr. 2015. Web. 28 May 2017.

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