Blacks and salt: Should the Dietary Guidelines single out African-Americans for low-sodium diets?

Health and medicine explained.
April 18 2011 3:07 PM

Black Salt

Should the government single out African-Americans for low-sodium diets?

Salty pizza. Click image to expand.
Should all African-Americans be advised to lower their sodium intake?

On Jan. 31, the departments of Agriculture and Health and Human Services released the newest version of the official Dietary Guidelines for Americans, billed as "the federal government's evidence-based nutritional guidance to promote health, reduce the risk of chronic disease, and reduce the prevalence of overweight and obesity through improved nutrition and physical activity."

The 100-plus-page report is full of sensible advice, including recommendations to avoid oversized portions, switch to low-fat milk, and drink water instead of sugary beverages. But one particular piece of advice has been making headlines: the government's strong warning that Americans need to reduce their salt consumption. In a separate report published last April, the Institute of Medicine noted that cutting the amount of salt in our diets could prevent more than 100,000 deaths each year.

The salt debate is certainly heated. But the government doesn't hedge any bets in making a "key recommendation" that Americans reduce their daily intake of sodium to 2,300 milligrams—about a teaspoon, or roughly the amount in 10 dill pickles. This alone poses a remarkable challenge; less than 15 percent of the population currently meets this target. But the Dietary Guidelines don't stop there. They also recommend reducing salt intake to 1,500 mg for people who are 51 and older or have hypertension, diabetes, or chronic kidney disease. And they set the same, more stringent goal for anyone—anyone at all—who happens to be African-American.

Advertisement

There may be reasonable, if not entirely obvious, reasons why older individuals and those with certain pre-existing medical conditions should make stronger efforts to reduce their salt intake. People with kidney disease, for example, have trouble shedding excess sodium from their body. But should the same rules apply to all black people? If these guidelines are evidence-based, what's the evidence that race—in and of itself, regardless of age, ailment, or other considerations—is a risk factor of the same consequence as, say, diabetes? Are discredited biological explanations for racial disparities in health hiding in these new nutrition guidelines?

This isn't the first time the government has made race-specific recommendations regarding salt intake; similar advice was put forth in the last version of the guidelines in 2005. However, these race-specific recommendations take on a new meaning within the emerging political climate of America's "war on salt." What's striking is that with regard to minority health, the new federal guidelines shift this conversation away from widespread public health initiatives—such as New York City's efforts to reduce salt in packaged and restaurant food by 25 percent over five years—and toward the idea that some races are biologically predisposed to certain diseases.

This stems from a decades-long debate over the disproportionately high rates of hypertension among blacks. Some studies have shown that blacks have greater "salt sensitivity" than whites, meaning that similar amounts of salt ingested by each group lead to greater increases in blood pressure among blacks. The latest edition of the Dietary Guidelines makes no assertion about the source of this disparity. Rather, it notes that, for whatever reason, blacks' "blood pressure ... tends to be even more responsive to the blood pressure-raising effects of sodium than others."

Yet what seems like a bland statement of fact leads all too easily to the idea that blacks' higher rates of sodium-related chronic diseases like hypertension stem from inherent biological differences rather than social, economic, or environmental pressures. Without a doubt, African-Americans have higher rates of hypertension than U.S. whites; research shows that the age-adjusted prevalence in blacks is 41.8 percent, versus 29.8 percent for whites. However, epidemiologist Richard Cooper has placed this and other racial disparities in an international context, showing that U.S. whites have a higher prevalence of hypertension than Nigerians, while U.S. blacks have a lower prevalence than Germans and Finns.

  Slate Plus
Slate Picks
Nov. 21 2014 1:38 PM What Happened at Slate This Week? See if you can keep pace with the copy desk, Slate’s most comprehensive reading team.