What’s Next on Salt
Beginning over one hundred years ago, increasingly sophisticated research has demonstrated that high sodium intakes boost blood pressure and increase the risk of stroke, heart disease, and kidney disease. As the decades passed, though, consumption remained high—about 50 percent higher than national recommendations—and, despite recommendations beginning in 1969 from physicians, health organizations, and others, the FDA did little. The most significant action was in 1990 when Congress passed the Nutrition Labeling and Education Act, which led the FDA to require Nutrition Facts labels on almost all foods. For the first time consumers could check sodium content and compare one brand to another. But it is debatable whether labeling had any significant effect on population-wide sodium consumption.
Sodium intakes have remained at about 3,400 milligrams per day, far higher than the recommended intake of under 2,300 mg per day. Experts, such as Tom Frieden, former director of the Centers for Disease Control and Prevention, and others have estimated that high-sodium diets (salt is the main culprit) have been causing as many as 100,000 preventable deaths annually. A preliminary study by the Department of Health and Human Services estimated that such a diet has been costing society—in the form of medical costs, time lost from work, and premature death—as much as $3.6 trillion over 20 years. Clearly, reducing sodium in processed and restaurant foods is one of the single most important actions that industry could do or government could mandate to improve the public’s health.
That is why in 2010 the Institute of Medicine (now the National Academy of Medicine) issued a major report calling on the FDA to set mandatory limits on sodium levels in restaurant and packaged foods. The FDA immediately said it would issue only voluntary guidelines, and it took the agency six years just to propose such guidelines. Fast forward past the do-nothing Trump administration to October 14 when the FDA at long last finalized those guidelines. With specific targets for 163 categories of food, from Cottage Cheese to Toddler Puffed Snacks, the guidelines call for an overall reduction of 12 percent over the next two-and-one-half years. The agency has yet to finalize its proposed 10-year guidelines, which are aimed at lowering average sodium intake to the recommended 2,300 mg per day.
The long delay in tackling the sodium problem has been due to several things. First and foremost was the predictable industry opposition to both voluntary guidelines (because they might lead to mandatory rules) and mandatory limits (because they would force potentially expensive reformulations and lower sales). Another force was the predictable opposition by anti-regulatory Members of Congress.
But another reason for inaction is the handful of observational studies that indicated that sodium intakes below about 3,000 mg and above about 5,000 mg per day increase the risk of cardiovascular disease (the notorious J-shaped curve). Those studies, led especially by researchers in the United States and Canada, were roundly, and justifiably, criticized from the day they were published. One tragic flaw was inaccurate measurement of sodium intake. The authors of the most-recent and -publicized studies, such as PURE, used one spot urine test at the beginning of their multi-year studies to gauge sodium intake. In contrast, multiple 24-hour urine collections are needed over the course of studies to measure sodium intake accurately. At least two research groups re-analyzed previous cohort studies and found that studies using multiple 24-hour urines demonstrated a direct relationship between sodium intake and cardiovascular disease, but using only the first collection led to an apparent J-shaped relationship.
A 2019 National Academy of Medicine report summarily dismissed the contrarian studies as having “methodological limitations” and “a high risk of bias,” in effect giving permission for the FDA to move ahead with guidelines. Now that the 2½-year guidelines are finalized, the FDA and health advocates need to consider what to do next. I recommend the following:
• The FDA should anoint a Salt Czar whose full-time job would be to press major chain restaurants and food processors to lower sodium levels in their products and to advise smaller companies on how to do the same. The czar should publicly applaud companies that made significant improvements and criticize laggards. And the czar should mount a well-funded education campaign encouraging consumers to read labels and choose lower-sodium products to protect their health.
• The almost-8-year gap between the 2½-year) and 10-year targets is far too long. Sodium reduction would almost certainly drop off the radar screens at both FDA and companies. To fix that, FDA should establish 6-year mid-point targets to keep the pressure on companies. Because it takes FDA nearly forever to finalize guidelines, that work should start immediately.
• Because the FDA’s whole plan is voluntary, many companies might simply ignore the targets. The FDA needs to have a contingency plan in case sodium intake does not decline sufficiently. One option would be to make the product-specific upper-bound targets mandatory. Another option would be to require front-of-package warning labels on products with sodium levels that have more significantly more sodium than the desired category-wide averages. Again, because of the long incubation times for regulations, FDA needs to start on both options (and possibly other measures) immediately.
Finally, there is a role for academic scientists. One reason that government action on sodium has taken so long is that no prominent scientist has made sodium-reduction a top priority, even a personal crusade. In contrast, in the United Kingdom, Graham MacGregor, at Queen Mary University of London, has devoted much of his career to both doing cutting-edge research on sodium and pressuring companies and the government to cut the salt. Largely because of his campaigns, sodium intake in the UK declined between 10 and 15 percent between about 2003 and 2011 (a change then in government largely eliminated the effort). Any takers in the United States and Canada?
Michael Jacobson is the co-founder and former executive director of the Center for Science in the Public Interest and the author of Salt Wars: The Battle Against the Biggest Killer in the American Diet (MIT Press). The views expressed here are not necessarily those of CSPI.