Is phosphate the next sodium – a once seemingly benign food additive now linked to heart disease and death? It is nearly as ubiquitous as sodium in processed foods but so under the radar, it is not even listed on food labels.
Phosphate’s low profile may soon change. A new Northwestern Medicine research center, funded by the American Heart Association (AHA), will investigate potential heart damage caused by excess dietary phosphate, particularly in African Americans, who have disparately high rates of cardiovascular disease and may consume diets high in processed foods.
The goals are to find new ways to prevent and treat heart failure and build evidence for regulating phosphate in the food supply to try to improve public health.
“Poor people and minorities are more likely to eat greater amounts of processed foods because those items are cheaper and more readily available, especially in neighborhoods where there is not a supermarket and limited availability of healthier fresh foods,” said lead investigator Dr. Myles Wolf, MD, director of the Institute for Public Health and Medicine – Center for Translational Metabolism and Health. “We think reducing dietary phosphate consumption in low-income and African American populations may reduce their higher risks of heart disease and, thereby, minimize one of the most glaring health disparities in the U.S.”
In the future, phosphate content may need to be listed on food labels, said Dr. Wolf, who is also the Margaret Gray Morton Professor in Medicine-Nephrology.
The Northwestern center will conduct three research projects to investigate phosphate-related damage on a public health, clinical science and molecular level. With a nearly $4 million grant, the center is one of four new AHA-funded centers on disparities in heart disease and stroke.
The studies will build on Northwestern research already linking a high-phosphate diet to an increase of a hormone, FGF23, that strongly predicts risk of heart failure and death. And that link, scientists believe, may explain the higher incidence of heart failure in poor people and minorities, who eat more of the phosphate-laden processed foods, thereby raising their levels of the hormone.
Nearly half of all African-American men and women have some form of cardiovascular disease, according to the AHA.
Food additives are the most absorbable source of phosphate in the human diet. They are commonly found in processed meats, packaged goods, fast food and processed beverages such as certain sodas, lemonades, bottled teas and other soft drinks. The food industry adds phosphate to processed foods to improve taste and appearance and extend shelf life.
“Any food item that’s wrapped in plastic has a good chance of having phosphate added to it,” Dr. Wolf said.
A healthy adult diet likely requires only 800 to 1,200 milligrams per day of phosphate, but a similar diet that substitutes processed foods for their fresh equivalents can contain closer to 2,000 milligrams of daily phosphate, according to research by Dr. Wolf’s team.
In an earlier study, Dr. Wolf and colleagues showed blacks and lower income individuals had higher phosphate and FGF23 levels in their blood than whites and people with higher incomes.
“Now we are trying to connect all the dots at a public health level,” Dr. Wolf said.