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

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

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.


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.


Moreover, there are no widely accepted biological explanations linking social categories of race to salt sensitivity and hypertension, despite common assumptions that a yet-to-be-found gene will answer all our questions. Several traits are known to influence salt sensitivity, such as age, weight, and diet. And hypertension is similarly linked to various behaviors and demographic factors beyond the slippery category of race; several research papers have shown an inverse relationship between socioeconomic status and blood pressure. At the same time, the National Poverty Center estimates that over 25 percent of blacks are poor compared with 9.4 percent of whites. If poverty leads to hypertension—perhaps mediated by chronic stress—then there's at least one alternate explanation for the racial disparity.

But the subtle ways that social factors might impact health are lost when federal guidelines lump in race with other risk factors that have well-defined physiological mechanisms. While made with the best intentions, the government's dietary recommendations strongly imply that blacks suffer from higher rates of salt-related chronic diseases because they are genetically different—and perhaps less resilient—while obscuring these health outcomes' social determinants.

Why should this matter? Regardless of any implication that blacks' worse health outcomes are linked to their own inherent deficiencies, isn't the simple purpose of federal nutrition guidelines to identify which groups should take extra precautions? Isn't this about health, not racial politics?

The truth is that they aren't mutually exclusive. Racial politics shape our understanding of health disparities more than we realize. For example, biological explanations of blacks' heightened salt sensitivity have led to theories like the "slavery hypothesis." According to this idea, endorsed by serious researchers as well as media luminaries like Oprah Winfrey, the ability to retain salt was advantageous for anyone enduring the grueling slave trade; surviving Africans who populated and reproduced in the New World are thought to have conferred this presumed, yet unproven, genetic trait—now, ostensibly, a disadvantage when salt is abundant—to their descendants.

While debunked theories such as this acknowledge that past wrongs perpetrated against blacks are relevant to understanding current health disparities, such a solitary focus on history does not fully engage with how modern injustices—from urban blacks' lack of access to healthy food to the environmental contaminants in their communities—also impact health. Indeed, these injustices "get under the skin" to produce the very disparities that are thought to be a simple part of who blacks are.

When the federal government endorses guidelines implying that innate, physiological differences are at the root of racial disparities in health, it ultimately disserves the very communities whose health it is trying to promote. America has a long history of using biological explanations to justify racial subordination. We run the risk of recreating similar types of injustices when we frame persisting health inequalities in biological terms instead of acknowledging other possible causes.

The federal government's misstep with its nutrition guidelines is not a reason for colorblind medicine. Reducing racial disparities in health necessarily begins with taking race seriously as a marker of social and economic differences that affect health. But we don't need to use race as a crude proxy for some unknown genetic factor that mysteriously produces drastic health disparities all by itself. It is past time that we take the social determinants of health seriously as a matter of public policy. By implying that blacks' higher rates of salt-related chronic disease stem from inherent biological differences, the new guidelines only rub more salt in the wound.