"Southern" diet linked to increased stroke

Pauline Anderson

February 13, 2013

Honolulu, HI- A diet rich in salty, high-fat fried foods and sugary drinks explains about 63% of the racial variation in stroke risk, a new study suggests [1].

"To me, the really interesting part of the study is that diet explains so much of the racial disparity between African Americans and whites," said lead researcher Dr Suzanne Judd (University of Alabama, Birmingham).

The study, the Reasons for Geographic and Racial Differences in Stroke (REGARDS), was presented here during the International Stroke Conference 2013.

Dietary patterns

The study included 30 239 participants age 45 years and older. There were an equal number of black and white participants.

Study subjects filled out detailed food frequency questionnaires. From these responses, and using a mathematical model, researchers came up with five dietary patterns:

  • Convenience (Mexican and Chinese food and mixed dishes with both meat and beans).

  • Plant-based (fruit, vegetables, fruit juices, cereal, fish, and poultry).

  • Sweets (added fats, bread, chocolate, desserts, sweet breakfast foods).

  • Southern (added fats, fried foods, organ and processed meat, and fatty milk).

  • Alcohol (beer, wine, liquor, green leafy vegetables, salad dressings, nuts and seeds, coffee).

In addition to being high in fried foods like chicken, liver, ham, and potatoes, the Southern diet includes lots of high-fat dairy, eggs, added salt, and sweetened beverages. For example, said Judd, Southerners will often put their tea on the stove to boil, allowing them to add more sugar. But the diet also includes green vegetables, like collard greens.

People following the Southern cuisine don't just fry their food; they also use unhealthy oils—for example, bacon grease instead of olive oil—to fry it in, said Judd. "Often in the South you'll see people render meat and keep the fat, the bacon fat, and fry okra or potatoes in it; so they're getting the bacon in their bacon and in their vegetables, too."

Gizzards, organ meats

The Southern diet includes meats high in saturated fat—such as organ meats and gizzards. "In a lot of Southern kitchens, people will use all parts of an animal—to flavor broths and stews—and they will use organ meats and cuts that you wouldn't see in other places," said Judd.

In terms of calories, the Southern diet does not differ that much from other diets.

The research showed that 10 states—Delaware, Louisiana, Mississippi, Alabama, Illinois, Georgia, Missouri, Arkansas, Michigan, and Maryland—had the greatest adherence to the Southern diet. Judd noted that seven of these states are Southern—thus the name for the dietary pattern.

The study showed a dose response related to the Southern diet and risk of stroke: those who ate Southern diet the most—about six times a week—had about a 30% increased stroke risk (hazard ratio 1.30, 95% CI 0.97-1.76; p=0.05), in a model adjusting for age, race, sex, smoking, and physical activity, compared with those who ate it about once a month, said Judd.

Racial disparity

Depending on the study, there is a two- to four-times increased risk of stroke among young African Americans compared with young whites, said Judd. Importantly, in this current study, when the Southern diet was added to the statistical model, the risk of stroke for blacks compared with whites was mediated by 63% (parameter estimate for HR for race in those under 65 years reduced from 1.38 to 1.12).

"The other part could be explained by genetics or other factors," said Judd.

Judd and her colleagues also ranked subjects according to how well they adhered to the plant-based diet. In both the highest- and second-highest-adherence groups, there was a 20% reduced risk of stroke. "As long as you were eating some (of the plant-based diet), it looked like it was protective," she said.

The research team plans to investigate this further. Is the increased stroke risk caused not only by eating unhealthy foods, but also by not eating enough healthy plant-based foods? "We'd love to look at that next—to find out whether it's the bad foods or the lack of good food."

She and her colleagues also hope to look at how the Southern diet might affect cognitive functioning. And they would like to learn whether being born in the South or moving there makes a difference to dietary habits.

Novel information

When asked to comment on the study, Dr Brian Silver (Rhode Island Hospital, Providence) called it "fantastic."

"The authors have done their homework in trying to really analyze in great detail the effects of diet on stroke risk," he said.

Silver said he was surprised to learn that almost two-thirds of the attributable stroke risk is due to diet. "That is novel information for certain. It tells us that we can't just blame our genes necessarily; we definitely do have to make efforts to try to fix our diet."

He wondered if people are "preprogrammed" genetically to eat the way they do or whether dietary choices are more influenced by culture. "What we do know now though is that it's changeable, because people were not this obese 100 years ago."

The REGARDS study was funded by the National Institute of Neurological Disorders and Stroke and a small grant from General Mills . The authors have no disclosures. Silver has no relevant conflicts of interest.


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