How many times have you heard that salt is bad for you? Many Americans have been led to believe that the less salt they eat, the healthier their diet will be. However, recent studies are showing that this may not be the case. So in terms of sodium intake, how low is too low? Is it time to reconsider the wisdom of low-salt diets? Yes! New research suggests that a low-salt diet may result in severe health problems and higher overall mortality, especially when combined with certain chronic health conditions and lifestyle factors.
The debate over sodium intake has reached new heights in recent months. Proponents of the low-sodium diet often cite the USDA and the American Heart Association, who advise limiting sodium to no more than 2300 mg per day and even as little as 1500 mg per day. However a 2014 study published in the New England Journal of Medicine finds that, contrary to popular thought, the low-sodium diet can actually be harmful to cardiovascular health.
According to the Wall Street Journal, “The new study, which tracked more than 100,000 people from 17 countries over an average of more than three years, found that those who consumed fewer than 3000 milligrams of sodium a day had a 27% higher risk of death or a serious event such as a heart attack or stroke in that period than those whose intake was estimated at 3000 to ,000 milligrams. Risk of death or other major events increased with intake above 6000 milligrams.”
The Journal continues, “The findings are the latest to challenge the benefit of aggressively low sodium targets—especially for generally healthy people. Last year, a report from the Institute of Medicine, which advises Congress on health issues, didn't find evidence that cutting sodium intake below 2300 milligrams reduced risk of cardiovascular disease.”
Supporters of low-salt diets often point to evidence that high sodium intake leads to high blood pressure. But low-salt diets cause changes too such as a rise in certain hormones and lipids in the blood. The American Journal of Hypertension published a 2012 study that found that people on low-salt diets experienced higher plasma levels of renin, cholesterol, and triglycerides. The study’s authors determined that the slight reduction in blood pressure was overshadowed by these unhealthy effects, and that low-sodium diets might have more severe consequences at a population level.
Additionally, severely limited sodium intake is associated with negative outcomes in people with type 2 diabetes. One 2011 study concluded that patients with type 2 diabetes on a low-salt diet are more likely to experience premature death than their non-low-salt-dieting counterparts. Furthermore, a 2010 Harvard study found a link between low-salt diets and an instant onset of insulin resistance, a condition that often leads to type 2 diabetes. These studies challenge the suitability of the accepted recommendation of low-salt diets for type 2 diabetics.
Sodium restriction can also have negative effects on athletes, especially those taking part in endurance sports such as marathon running, rowing, cross-country skiing, and triathlons, among others. Researchers conducting a study following marathon runners have found that endurance athletes frequently develop hyponatremia (or low blood sodium). During the 2002 Boston Marathon, approximately 13% of 488 runners who participated in the study had hyponatremia, and additional studies of other endurance events have found the frequency of hyponatremia to be up to 29%.
Finally, the elderly are at a special risk when following a low-sodium diet. Senior citizens with hyponatremia often experience more falls and broken hips as well as a reduction in cognitive abilities. Hyponatremia is all too common in the elderly, especially those with an acute illness. This is another population at risk for detrimental health effects due to the near-universal acceptance of the low-sodium diet.