Studying the healthy food choices of African American pregnant women in St. Louis, a Washington University scientist using March of Dimes-funded data made two interesting findings: women who lived closer to fast food chains ate more legumes than those who lived farther, and women who lived farther from grocery stores ate more legumes than those who lived closer.
The counterintuitive associations between increased intake of legumes and proximity to fast food and longer distances to grocers, recently published in the "International Journal of Environmental Research and Public Health", needs further research to understand the why behind the link, said study first author Dr. Najjuwah Walden, a postdoctoral research associate in the department of psychiatry at Washington University School of Medicine in St. Louis.
Still, Dr. Walden has a hypothesis about the behaviors that fueled the legume findings: study participants who ate the most legumes likely bought them at fast food chains near their homes — not nearby grocers.
“I designed this study with a bias that grocery stores are healthy, fast-food restaurants are not, and closer proximity to healthy places is associated with healthier intake,” Dr. Walden, who specializes in nutritional psychiatry, said. “But the reality wasn’t that rigid. Healthy foods can still be chosen in unhealthy environments. And rather than criticizing fast food restaurants as places where legumes shouldn’t be purchased, the alternative is to evaluate these choices as exemplars of how African American women want legumes to be prepared.”
“That’s incredible insight for food programs that value food preferences.”
For example, Dr. Walden said, instead of eating legumes like chickpeas or lentils, which are the primary legume references for the Mediterranean diet, her other research has found that many African American women prefer consuming black-eyed peas and pinto beans, which are commonly sold at fast food restaurants and prepared in a certain way.
But in many cases, food and nutrition aid programs for low-income pregnant women, like the federally funded WIC program (the Special Supplemental Nutrition Program for Women, Infants, and Children), may not make recommendations that mirror the food preferences of the populations they serve, she said.
“These findings point to the invaluable nuances of nutritional counseling for diverse pregnant populations,” Dr. Walden said. “Just a little bit of education for nutrition counselors and low-income pregnant women about the various iterations of an anti-inflammatory diet in pregnancy can go a long way.”
“For example, since previous research has shown that people won’t eat what they don’t want to eat, why not use existing support systems, like WIC, to find out what part of a pregnant woman’s diet is already healthy, and encourage her to eat more of that?”
Dr. Walden’s study began with a March of Dimes-funded pregnancy dataset from Washington University School of Medicine. Dr. Walden merged that data, which included residential addresses and dietary patterns of 87 African American pregnant women in the St. Louis metropolitan area from 2018-2020, with corresponding ‘food environment’ maps that logged each pregnant woman’s residential proximity to restaurants, convenience stores, and grocers.
Then, using statistical modelling, she ran an analysis to see if there were any associations between participants’ self-reported consumption of nutrient-dense, anti-inflammatory foods and their proximity to grocery stores or fast-food chains. Those nutrient-dense foods, which were listed in a survey the pregnant women in the March of Dimes dataset filled out about their eating habits, were dark-green leafy vegetables, red-orange vegetables, melon, berry and citrus fruits, nuts and seeds, legumes, and fish.
Of all those, Dr. Walden’s study found legumes to be the only food group that had an association with proximity to any food vendor — and that included increased intake with closer proximity to fast food. Dr. Walden said that while the statistical model didn’t quantify how much more legumes women near fast food were eating, she said “the difference was significant.”
For all other nutrient-dense foods analyzed, the study found no link between consumption frequency and proximity to a specific food vendor. In other words, when it came to consumption of fruits, fish, nuts and seeds, and colored vegetables, women who lived near grocery stores and fast-food chains ate the same amounts.
Dr. Walden said the reason for this is likely two-fold. First, it’s likely consumption of these other categories of foods was low among women who lived both near grocers and fast food. Second, the anti-inflammatory food choices on the survey were limiting.
“That’s one of the study limitations,” she said. “Only a narrow variety of foods was included on the survey, and if apples, or collard greens, or sunflower seeds were among the foods the survey asked about specifically, we may have seen more associations.”
“Still, this research is a good start in unpacking these vital nuances.”