By Dr. John Bagnulo, Director of Nutrition
A great paper in the New England Journal of Medicine (2014) showed that sodium consumption between 3g (3000mg) and 6g (6000mg) was associated with the lowest risk of both cardiovascular-related and non-cardiovascular-related mortality.
The evidence: Researchers measured how much sodium and potassium was excreted in 24-hour collection urine samples (a great way to measure our sodium and potassium intake because of how closely guarded the body’s levels are) in nearly 102,000 individuals from 17 countries. Individuals who retained the most sodium (a sign that the body is generally not getting enough) and those that excreted more than 7g the next morning both had significantly greater risks when followed for about four years.
This study contradicts the American Heart Association’s recommendation of less than 1500mg per day as well as the USDA guideline of less than 2300mg per day, but it isn’t the first study to raise eyebrows.
Earlier investigations have shown that there is no linear relationship between salt intake and blood pressure, something that a lot of us have been led to believe. And salt restriction/low-sodium diets never seem to produce the reversal or even reduction in hypertension that we expect. So what is really going on with this nutrition conundrum?
Sodium and chloride are both critical micronutrients. Sodium intake at less than 500mg per day becomes fairly dangerous, and relatively quickly. Fortunately, these intakes in the U.S. are rare because so many foods (any animal product, for instance, and many vegetables) contain naturally occurring sodium.
But even levels below 1000mg per day can cause issues that range from insomnia to poor nervous system activity and an inability to adapt to stress. Chloride is required for hydrochloric acid production by the stomach, essential for initiating digestion. Low salt intake has also been associated with poor digestive function, especially of HCL-dependent protein digestion.
There are so many variables that can influence a person’s need for sodium, salt, or both. Sweating, water intake, the amount of dietary carbohydrates, age, other micronutrient levels … the list goes on.
As is the case with so many nutrition and health issues in America, there is a distinct dichotomy. Millions of Americans are just trying to put food on the table every day, and much of that cheap, heavily processed food contains too much sodium. Others are trying to follow the standard recommended guidelines: Eat less sodium, drink more water, sweat more. Additional advice might include: Eat more fruits and vegetables, fewer carbohydrates, and even try fasting!
If one were to follow all of this advice, combined with a sodium-restricted diet (less than 1500mg per day), they could experience some really troubling symptoms. Even the 2300mg ceiling recommended by the more conservative USDA guidelines might not be enough.
Here are some numbers to consider:
• ¼ tsp of salt = 1.4grams of sea salt = 500mg of sodium
• Two to three cups of coffee = 47 percent more sodium loss through the kidneys
• Low-carb diet = increased sodium loss
• Increased physical activity, especially in warmer weather = increased sodium losses
My recommendation: Choose unrefined sea salt or Himalayan salt if you don’t mind spending a little more. Otherwise, follow your taste in the case of salt. If you can measure out a teaspoon or two and can see how it fits in with your cooking and tastes, you will be headed in the right direction!
Urinary Sodium and Potassium Excretion, Mortality, and Cardiovascular Events. N Engl J Med 2014;371:612-23. DOI: 10.1056/NEJMoa1311889 Copyright © 2014 Massachusetts Medical Society. http://www.nejm.org/doi/pdf/10.1056/NEJMoa1311889
Dr. John Bagnulo is Director of Nutrition at Functional Formularies, and leads nutrition and research and development initiatives. Learn more about Dr. Bagnulo here.