Southern diet helps explain extra high blood pressure risk for black men

(Reuters Health) - High blood pressure is widespread among African-American men at least in part because they’re more likely than other people to eat a traditional Southern diet with lots of fried and fatty foods, a U.S. study suggests.

Researchers followed 6,897 people in the South who didn’t have high blood pressure in 2003-2007, including 1,807 African-American men and women. After about 9 years, 46 percent of black participants and 33 percent of white participants developed high blood pressure.

Among all men, a traditionally Southern diet was associated with a 16 percent higher risk of developing high blood pressure, and for women, a 17 percent increased risk. As a group, African-American men ate a more traditionally Southern diet than other men or women in the study, and this explained more than half of their increased risk for high blood pressure, or hypertension, researchers found.

“It is interesting that diet more than being overweight was the biggest contributor to the racial disparities in hypertension,” said lead study author George Howard of the Ryals School of Public Health at the University of Alabama at Birmingham.

“This would suggest we might want to consider interventions to increase health foods in the diet while minimizing fried foods and processed meats,” Howard said by email.

While the current study wasn’t designed to prove whether or how certain eating habits might directly impact the development of high blood pressure, previous research has linked the so-called DASH diet recommended by the American Heart Association to a lower risk of hypertension, Howard said.

Among people who follow the Dietary Approaches to Stop Hypertension (DASH) diet with increased lean proteins, fruits, vegetables and whole grains there isn’t as big a difference in high blood pressure rates between white and African-American individuals, Howard noted.

“This diet has been shown again and again to protect the heart,” Howard added.

By contrast, a traditionally Southern diet is full of foods that the DASH diet advises people to avoid: fried foods, organ meats, processed meats, eggs, added fats, high-fat dairy, bread and sodas and other sugary beverages.

For African-American women in the study, the Southern diet explained 29 percent of their excess risk for high blood pressure.

Even though a Southern diet rich in fried foods and saturated fat can indeed contribute to high blood pressure, this isn’t the only factor that matters, stressed Dr. Clyde Yancy, chief of cardiology at Northwestern University’s Feinberg School of Medicine in Chicago. Obesity, income, education, can also influence blood pressure, and sodium intake matters for women in particular, Yancy, who wasn’t involved in the study, said by email.

“As we continue to explore how best to measure the impact of social determinants of health, we are learning how difficult it is to disaggregate singular variables and assign causality,” Yancy added. “It may ultimately be best to remain global in our scope - focusing on essential needs like education, housing, employment and access to healthy foods - as we address the unique burden of disease in at-risk communities.”

The study found eating lots of sodium and having no education beyond high school each explained about 12 percent of the excess hypertension risk for African-American men.

Among African-American women, obesity explained 18 percent of their extra risk for high blood pressure, and having a large waist circumference explained another 15 percent of the added risk.

The American Heart Association defines hypertension, or high blood pressure, as a systolic reading of 130 mmHg or higher and diastolic readings of 80 mmHg or higher. Systolic pressure reflects the pressure blood exerts against artery walls when the heart beats. Diastolic pressure indicates the pressure when the heart rests between beats.

Excessive amounts of fat and sodium in traditional Southern diets can lead to high blood pressure, said Daniel Lackland, a researcher at the Medical University of South Carolina in Charleston who wasn’t involved in the study.

“A high fat diet is associated with stiffer arteries, which are associated with high blood pressure,” Lackland said by email. “A high salt diet is associated with retention of fluid and higher blood pressure.”

SOURCE: JAMA, online October 2, 2018.