Needs More Salt

The FDA failed to conduct a peer review of its questionable scientific findings on sodium intake and did not respond to inquiries questioning the accuracy of its information.

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One year ago, the Food and Drug Administration issued Guidance for Industry, a document setting out goals to reduce sodium content—generally found as sodium chloride (salt)—in commercially processed, packaged, and prepared foods. Shortly afterward, the Competitive Enterprise Institute submitted a request for correction (RFC) of the guidance under the Information Quality Act (IQA). Defying a requirement to respond within 60 days, the FDA has not replied.

The Competitive Enterprise Institute (where I am a senior fellow) filed the RFC—an administrative mechanism to seek correction of inaccurate agency information—because the FDA failed to conduct a peer review of its scientific findings before issuing guidance that may harm more people than it helps. This is an important safeguard under the IQA, which Congress enacted to ensure the “quality, objectivity, utility, and integrity of information (including statistical information) disseminated by Federal agencies.”

Agencies issuing “influential” scientific information—defined as having a “substantial impact on important public policies or important private sector decisions”—must conduct a pre-dissemination peer review utilizing qualified and independent specialists in the relevant field who were not involved in producing the agency’s draft. Guidelines setting sodium-concentration targets for all “Commercially Processed, Packaged, and Prepared Foods” in the more than $2 trillion food service and retailing industry are clearly “influential.” And while the guidance is technically voluntary, the FDA has indicated that it will “specifically encourage attention by” food manufacturers with large market share, as well as national restaurant and retail food chains.

Yet the FDA failed to conduct a peer review. Further, the agency’s own scientific review, while quite detailed, failed to acknowledge considerable uncertainty in the field.

The guidance is based on the premise that lowering sodium intake, regardless of individuals’ current intake levels and health status, will lower blood pressure and, in turn, reduce the incidence of cardiovascular disease and death. Sodium consumption is linked to the development of hypertension, a leading cause of heart disease and stroke, but the connections are not straightforward.

A 2020 review of randomized controlled trials—the gold standard for scientific studies—assessing the effect on blood pressure and potential side effects of reducing salt intake by the highly respected Cochrane Library found a minuscule (0.3 percent) decrease in blood pressure in white people with normal blood pressure and a small decrease (about 3.5 percent) in people with elevated blood pressure. A few trials suggested these effects may be somewhat greater in black and Asian people. But these minimal benefits carried health costs. Sodium reduction resulted in significant increases in cholesterol and triglycerides—both associated with cardiovascular disease—which were more consistent than the blood pressure declines, especially in non-hypertensive people.

Instead of targeting sodium reduction at the hypertensive population most likely to benefit, the FDA guidance prescribes it for everyone. And the guidance fails to distinguish between people with high sodium intakes and those with normal or low sodium intakes.

Multiple studies suggest that low sodium intake can be just as detrimental as high sodium intake, leading to increased risk of cardiovascular disease and death in “those with or without hypertension.” A prospective trial in the prestigious New England Journal of Medicine found that daily sodium intake between three and six grams (g) per day—a range consumed by most of the world’s population, including in the U.S., where the average is 3.4 g—was associated with a lower risk of death and cardiovascular events than was either a higher or lower estimated level of intake.

In fact, sodium intake has been remarkably uniform worldwide over time. An analysis of 190 peer-reviewed studies found a narrow range of 2.6 g to 4.8 g per day that was reproducible over five decades and 45 countries with diverse populations, eating habits, and food industries. The average daily intake of 3.7 g was higher than the U.S. average.

Last year, researchers concluded that the available evidence shows the optimal level of sodium intake is between three grams and five grams per day. Since 80 percent of Americans have daily intake below five grams, the authors argued that “efforts to reduce sodium intake in entire populations cannot be justified.”

Sodium reduction should be targeted at hypertensive people with high-sodium diets. The FDA’s indiscriminate guidance may actually increase cardiovascular disease and death for many Americans.

The point of the pre-dissemination peer-review requirement is to resolve scientific uncertainties before agencies issue guidance that will have enormous health and economic consequences. But despite learning of its procedural lapse and the outstanding scientific issues a year ago, the FDA has yet to act.

Read the full article at City Journal.