Dietary dogmas die a slow, sometimes drawn-out death. This seems to be especially true for sodium, largely because such respected organizations as the CDC, FDA and AHA (American Heart Association) have circled the wagons on salt restriction.
Despite growing evidence that suggests the kind of sodium reduction recommended by these public health organizations may be misguided, the leadership appears unwilling to change course. The latest salvo in the salt wars comes straight from pages of The New England Journal of Medicine (Aug. 14, 2014).
Should you have read the headlines a few weeks ago you would be forgiven for feeling confused. The media did not know what to make of the two contradictory articles and an editorial published in this highly regarded medical journal. Just look at these completely clashing headlines from the week of August 11, 2014.
“Death By Salt? New Study Finds Too Much Sodium Is A Global Killer” –NPR
“1.6 Million Heart Disease Deaths Every Year Caused by Eating Too Much Salt” – Healthline News
“Pour on the Salt? New Research Suggests More Is OK” – NBC News
“Low-Salt Diets May Pose Health Risks, Study Finds” – Wall Street Journal
No one could blame you if you are confused by these mixed messages. So, what are we to believe? Salt is a killer or low-salt diets actually harm our health?
The study that advised Americans to cut back on salt was based on previous research and involved complex mathematical modeling. In essence, the Harvard researchers crunched a lot of numbers and concluded that extra salt in the diet was causing 1.6 million extra deaths annually around the world.
The contradictory study was based on calculations of sodium intake and health outcomes. The researchers tracked over 100,000 adults from 18 countries. They measured sodium excretion by testing morning urine samples, a good way of assessing how much salt people consumed the prior day. The conclusions:
“In this large, international, prospective cohort study, we investigated the association between estimated sodium and potassium excretion (used as surrogates for intake) and the composite of death and cardiovascular outcomes. The lowest risk of death and cardiovascular events was seen among participants with an estimated sodium excretion between 3 g per day and 6 g per day. Both higher and lower levels of estimated sodium excretion were associated with increased risk, resulting in a J-shaped association curve.”
OK, that’s doctor talk. What does it mean in plain English? Basically, it’s the story of Goldilocks and the porridge–not too hot, not too cold. It boils down to moderation. These researchers found that if you keep your sodium intake between 3,000 and 6,000 mg daily, you are likely to have the best outcome.
That is way more than the CDC and the AHA recommend. These public health officials want everyone over the age of 50 to keep their total sodium intake to less than 1,500 mg of sodium daily. That is a good bit less than a teaspoon of salt daily. That means food is quite bland and most people find it unpalatable.
To give you some sense of how many people actually attain that goal, here is what the researchers found. Less than 4% of the population surveyed actually achieved sodium intake in line with guidelines from the American Heart Association and the CDC. More important, though, was the finding that restricting salt intake to the recommended levels (less than 1,500 mg of sodium daily) was associated with worse health outcomes. Equally, excessive salt intake (over 6,000 mg of sodium daily) was also associated with negative results. The sweet spot was 3,000 to 5,999 mg of sodium daily, which is twice to four times more salt than our public health officials recommend.
This is not the first time very low sodium intake has been linked with an increased risk of cardiovascular disease or death. Here are just a few other articles that suggest too little or too much sodium could be dangerous:
“Compared with usual sodium intake, low- and excessive-sodium diets are associated with increased mortality: a meta-analysis.” American Journal of Hypertension (online, April 26, 2014)
“Estimated urinary sodium excretion and risk of heart failure in men and women in the EPICNorfolk study.” European Journal of Heart Failure (online, January 20, 2014)
“Urinary sodium and potassium excretion and risk of cardiovascular events.” (JAMA, Nov. 23, 2011).
“The association between dietary sodium intake, ESRD, and all-cause mortality in patients with type 1 diabetes.” Diabetes Care, April, 2011.
What’s the Bottom Line on Salt?
Despite an unwavering conviction that all African Americans, people with diabetes or hypertension and everyone over 50 should get sodium intake below 1,500 mg daily, there is no actual research proving that doing so will prolong life or improve health outcomes. That is not just our opinion. That is the conclusion of the most prestigious group of medical experts in America, The Institute of Medicine.
How is this possible? As we said at the outset, beliefs die hard and the conviction that salt is the enemy has been firmly entrenched for decades. Although most public health experts and health professionals embrace the concept of “evidence-based medicine,” they have a hard time accepting new data that contradicts long-held dogma.
The idea that low levels of sodium could have negative health consequences is a man-bites-dog story that challenges everything people have been taught. But here’s the explanation. When sodium intake drops below 1,500 mg per day, some people develop a stress reaction. Remember, sodium is essential for life. Low levels of sodium can trigger adrenaline (epinephrine) release along with increases in insulin, lipids like cholesterol and stress hormones such as renin, angiotensin and aldosterone.
A review article in The American Journal of Medicine (November 2013) titled: “Dietary Sodium Restriction: Take It with a Grain of Salt,” summarized the situation far better than we ever can:
There is no conclusive evidence that a low sodium diet reduces cardiovascular events in normotensive and pre-hypertensive or hypertensive individuals. On the contrary, there is sound evidence that a low sodium diet leads to a worse cardiovascular prognosis in patients with systolic congestive heart failure or type 2 diabetes mellitus. Worldwide sodium restriction, through its adverse effects on insulin resistance, may lead to an increase in the rates of type 2 diabetes mellitus…Advising low sodium diets seems misguided and potentially dangerous and illustrates the problem of guidelines based on flawed studies using surrogate measures.”
Want to know more about what you can do to reduce your risk of high blood pressure and heart disease without resorting to a low-sodium diet? Our book, Best Choices from The People’s Pharmacy provides a great many non-drug options that are affordable, low-risk and surprisingly easy to adopt. You will learn more about the contentious salt wars and find foods that can lower blood pressure about as well as many medications.
Share your own salt story below in the comment section.