Patient advocates warn FDA proposal on salt intake could do fatal harm to people with kidney disease

WASHINGTON — Patient advocates are warning that a recent proposal from the Food and Drug Administration meant to reduce consumers’ salt intake could inadvertently kill those with kidney disease, particularly Black Americans.

The proposal at issue, which is still in draft form, was unveiled by the FDA in April. It would allow the use of salt substitutes in foods that have so-called standards of identity, regulations governing what ingredients must go in popular foods, like ketchup, Asiago cheese, and white bread. Under current rules, food makers cannot use salt substitutes in these products, because the regulations call specifically for table salt.

Kidney advocacy organizations are warning that the proposal could lead to unnecessary deaths because the regulation would increase the use of one popular salt substitute: potassium chloride. Patients with chronic kidney disease, including end-stage renal disease, can’t properly excrete potassium from their bodies and excess potassium levels in the blood, known as hyperkalemia, can lead to cardiac arrhythmias and sudden heart failure.

In joint comments to the FDA, the American Association of Kidney Patients, the Academy of Nutrition and Dietetics, and the National Kidney Foundation warned that the proposal could particularly impact Black Americans, who historically have higher rates of kidney disease.

“The risks associated with the adoption of potassium-based salt substitutes would create more structural injustices and an additional layer of health disparity on an already stressed population,” the groups wrote. “Any action by the FDA to move forward with this rule directly conflicts with the missions of our organizations and the lives of the patients and families we serve.”

Those groups argue that the FDA’s proposal is particularly risky because an estimated 90% of people who have chronic kidney disease don’t know they have it, and don’t know to watch their potassium intake.

“Adding ‘hidden potassium’ in the form of potassium chloride substitutes to the American diet is a risk that should not be taken,” the groups wrote.

Despite the risks, the proposal could be a major win for public health overall. Studies have estimated that roughly 1.65 and 1.89 million deaths worldwide are caused by excess salt intake. Public health advocates, including the Center for Science in the Public Interest and the American Heart Association, have endorsed the FDA’s proposal, though they have called for safeguards to protect kidney patients.

The meat, packaged food, and dairy industries all are vocally supporting the policy as well, because it would allow them to reduce the sodium content in their foods without seriously impacting taste. The North American Meat Institute wrote in its comment to the FDA that allowing salt substitutes, “either alone or as a combination of ingredients, facilitates meeting consumer expectations for flavor and functionality by recognizing the important and varied roles that sodium chloride plays in food processing.”

The dust-up is an example of challenges the FDA faces in crafting sodium reduction policies for a country of more than 335 million people, who on average consume 3,400 milligrams of salt per day. Current dietary guidelines recommend adults consume no more than 2,300 milligrams of salt per day, but the FDA has struggled to find a way to dramatically cut Americans’ salt intake amid pressure from food companies that argue that sodium is not only a flavor enhancer but an essential preservative.

Public health advocates have called for mandating food companies to lower their sodium levels, as has the World Health Organization, but the FDA has declined to do so. Instead, it has set voluntary sodium reduction targets over the course of several years. Even then, food makers have argued that the FDA’s goals are difficult to achieve and that they need more time to reduce their products’ salt content. The FDA has said that allowing greater use of salt substitutes is one way the agency is helping food companies meet their voluntary salt reduction targets.

A similar debate over the relative risks of potassium chloride occurred in the United Kingdom nearly a decade ago. An expert panel convened by the U.K. government in 2013 estimated that while increased use of potassium chloride would lead to fewer strokes and lower blood pressure on a population level, it would also lead to a 2.2-fold increase in life-threatening cases of hyperkalemia.

Public health groups here in the U.S. insist that the policy can be crafted in a way that doesn’t put kidney patients at outsized risk. The American Heart Association is recommending, for example, that the FDA do similar modeling studies here and that regulators consider running an educational campaign explaining the policy change, as well as requiring labeling on foods that have replaced salt with potassium chloride.

Kidney advocacy organizations are pushing for similar labeling too. “If the agency chooses to move forward with the inclusion of potassium-based salt substitutes, it is strongly recommended that it include clear labeling of the added potassium to support high-risk populations making safe food choices,” the groups wrote.