Americans have been told for more than 50 years that they should cut back on salt. Doing so was supposed to help lower blood pressure. That in turn would theoretically reduce the risk of heart failure, heart attacks, strokes and kidney problems. Despite the widespread belief that salt is the enemy, a number of studies have questioned the value of a low-salt diet. Now the Food and Drug Administration is urging food companies to cut back on the amount of salt that they put in their processed foods. That’s not a bad thing, but will it accomplish the goal of reducing cardiovascular disease? A new study suggests it might.
You and the Salt Shaker:
When you sit down to enjoy a meal, do you usually reach for the salt shaker? A study of half a million people participating in the UK Biobank found that those who add salt most frequently may be shortening their lives (European Heart Journal, July 10, 2022).
Researchers analyzed data from 501,379 participants who completed a questionnaire at baseline. It included a question on how often they add salt to foods, not counting any salt added during cooking. Those who said they frequently add salt at the table also tended to have higher levels of sodium in their urine. That’s the best way of verifying the accuracy of dietary surveys.
The scientists had nine years of follow-up data that included 18,474 premature deaths. Those who were most likely to add salt to their food were about 28 percent more likely to die during that decade.
The Conclusions from the authors about high-salt vs. low-salt:
“Our findings indicate that higher frequency of adding salt to foods is associated with a higher hazard of all-cause premature mortality and lower life expectancy.”
There is one big caveat, though. This connection is strongest for people who don’t consume much in the way of fruits and vegetables. The scientists calculate that a 50-year-old woman who doesn’t eat much produce shortens her life expectancy by about a year and a half if she adds salt to almost every meal.
The FDA: “Lowering Sodium in the Food Supply”
The FDA revealed its “Sodium Reduction” plan on October 13, 2021. The agency wants to improve low-salt consciousness. The goal: move people from their current daily average sodium intake of 3,400 mg closer to the 2,300 mg limit “recommended by federal guidelines for people 14 years and older.”
Most of our salt comes from commercially-prepared foods like bread, crackers, soups, salad dressing, pudding, pizza and other packaged products. The FDA is hoping that companies will be able to reduce sodium in their foods so that American can get about 3,000 mg a day, a 12% reduction. The hope is that this modest salt reduction might have health benefits, especially for people at risk for high blood pressure.
The AHA Wants You to Go Low-Salt Intense!
The American Heart Association recommends limiting sodium intake to half that amount or 1,500 mg daily. Not all researchers are convinced such an aggressive goal is practical or truly beneficial.
A study in Lancet (Aug. 11, 2018) a few years ago recruited 95,000 volunteers from 18 countries. These subjects were followed for about eight years. Those who got moderate amounts of salt from their diet—about 3 to 5 grams of sodium daily—had slightly lower blood pressure, but no benefit against heart attacks and strokes. Once people exceeded 5 grams a day, they were at much higher risk of cardiovascular complications.
Why the Salt Wars Remain Unresolved:
Despite hundreds of studies and decades of debate, scientists cannot agree about the dangers of salt. Most of the sodium guidelines are based primarily on salt restriction during relatively short-term clinical trials.
It will come as a shock to many health professionals to learn that the data linking low-salt diets to improved blood pressure are not impressive. Some studies show a very modest reduction while others show virtually no benefit. There is even data suggesting increases in blood pressure on a very low-salt diet.
In 2006, the Second National Health and Nutrition Examination Survey (NHANES II) included more than 7,000 people. They were followed for nearly 14 years. The results baffled physicians. That’s because the results defied conventional wisdom.
People who consumed less sodium were more likely to experience fatal heart attacks or strokes (American Journal of Medicine, March, 2006).
The authors were cautious in their conclusion, but could not discount their findings:
“The inverse association of sodium to CVD [cardiovascular disease] mortality seen here raises questions regarding the likelihood of a survival advantage accompanying a lower sodium diet. These findings highlight the need for further study of the relation of dietary sodium to mortality outcomes.”
The Low-Salt Controversy Continues:
It’s hard to admit that you made a mistake. Many people dig in their heels and find ways to rationalize their point of view. That’s true in health as well as in politics.
The American Heart Association (AHA) has been pushing the public for years to reduce sodium intake to less than 1,500 mg daily. Their experts believe that salt raises blood pressure and consequently increases the risk for heart attacks and strokes. In our opinion this is a case of beliefs vs.data.
Very few people actually achieve the goal of limiting sodium intake to 1.5 grams or less. To do that, you would have to completely eliminate the salt shaker from the table. More importantly, you would have to avoid most processed foods, including soup, sandwiches, bread, crackers, chips, salsa, pizza, bacon, salad dressing, cereal and cookies. That might not be a bad thing, but for other reasons than salt.
Eating out in a restaurant would be forbidden. We wonder how many of the execs at the AHA avoid restaurants and achieve their own goal of less than 1.5 grams of sodium a day. I would love to organize an experiment where we collect the urine of the top 10 leaders at the AHA to analyze their sodium intake!
Low-Salt Heresy:
How good is the evidence behind the low-salt policy? Over the last several years a number of studies have questioned the benefits of drastic salt restriction.
One published in The Lancet included data on approximately 95,000 middle-aged people in 18 different countries (Aug. 11, 2018). Urine tests were used to measure sodium and potassium intake, and the scientists followed up on their subjects for about eight years. They got information on blood pressure, strokes, heart attacks and deaths.
At moderate levels of intake (3 to 5 grams daily), increased sodium did raise blood pressure a little bit, but it lowered the risk of dying from a heart attack. People who consumed the least sodium were more susceptible to heart attacks and strokes. That flies in the face of the AHA recommendations.
Dr. Andrew Mente, the lead author on the study, notes that most people around the world consume between 3 and 5 grams of sodium daily. He suggests that such levels may actually be healthful. Of course the experts at the AHA probably consider such a statement heretical.
Dr. Mente told Science Daily (Aug. 9, 2018):
“The World Health Organization recommends consumption of less than two grams of sodium — that’s one teaspoon of salt — a day as a preventative measure against cardiovascular disease, but there is little evidence in terms of improved health outcomes that individuals ever achieve at such a low level…
“In communities that consumed less than five grams of sodium a day, the opposite was the case. Sodium consumption was inversely associated with myocardial infarction or heart attacks and total mortality, and no increase in stroke”
Martin O’Donnell is a colleague of Dr. Mente and one of the co-authors of the new report.
He also shared his thoughts with Science Daily:
“There is no convincing evidence that people with moderate or average sodium intake need to reduce their sodium intake for prevention of heart disease and stroke…”
Does a Low-Salt Regimen Make a Difference?
A controlled trial in a retirement home compared low-salt and high-salt meals (Nutrients, March 16, 2021). The 20 volunteers (all over 60 years old) were provided three meals and two snacks a day for two weeks. The researchers relied on systolic blood pressure (the upper number) and urinary sodium-creatinine ratio as their main markers. The urinary ratio showed that the participants were following the plan. Systolic blood pressure was in fact 5 mm Hg lower on low-sodium meals. However, this difference was not significant. Moreover, two weeks is not long enough to assess health benefits or risks.
Too Much Sodium Is NOT a Good Thing!
People who consumed a lot of sodium (more than 5 grams a day) not only had elevated blood pressure but also a higher risk of strokes. Most of them were in China, where the source of sodium on the table is soy sauce rather than the salt shaker. Very few Americans consume more than 5 grams daily unless they are really working at it.
The most striking finding: more potassium is protective. People who got more potassium had a lower likelihood of heart attacks and strokes than those who consumed less. Perhaps this is why vegetables and fruits are so beneficial in our diets.
The Salt Wars Rage On:
The World Health Organization and the American Heart Association are big public health bodies. We assume that they are trying to do the right thing by their constituents. Large organizations have a hard time admitting that they may have relied more on belief than data. We have never understood why such entities cannot bring themselves to revise their guidelines in the face of new data.
We wish the execs at AHA would look at data suggesting a very low sodium diet could backfire. A meta-analysis of 25 prior trials concluded that very low sodium and very high sodium intakes were both associated with an increased risk of death (American Journal of Hypertension, Sept. 2014). Put simply, the guidelines might be hurting people rather than helping them.
Dr. James DiNicolantonio of Saint Luke’s Mid American Heart Institute has been critical of the move to restrict salt to extremely low levels.
In an analysis, he joined with cardiologist James O’Keefe to conclude:
“Prospective studies support the notion that those consuming the lowest amounts of salt are at the highest risk of cardiovascular events and premature death” (Current Opinion in Cardiology, July 2018).
Perhaps it is time, as Drs. O’Keefe and DiNicolantonio suggest, for dietary guidelines to be changed. Salt, in moderation, is not our enemy. Potassium is our friend, especially when we consume it in fresh fruits and vegetables.
What Do You Think?
You can listen here to our interview with Dr. Mente from 2016, before the most recent research was published. We have also interviewed Dr. Franz Messerli, an international blood pressure expert, on the question of sodium intake. Should you wish to listen more, here is our interview with Dr. James DiNicolantonio on the shifting recommendations regarding sodium.
We tend to steer clear of extremes. We tend to follow the Goldilocks principle: Not too hot or too cold. Not too much or too little. We think that heavy salt-shaker use at every meal is a mistake. We find that the AHA’s low-salt or no-salt approach unappealing. Moderation in all things seems like a healthy strategy for most folks.
How do you deal with the contradiction between the sodium guidelines and the confusing data we have presented? We would love to receive your feedback in the comment section below.
