Black Americans’ fruit and vegetable intake increased by 32 percent for each additional supermarket in the neighborhoods where they lived, according to a new University of North Carolina at Chapel Hill School of Public Health study.
White Americans’ fruit and vegetable consumption increased by 11 percent with the presence of one or more supermarket in their neighborhoods, the study showed.
“We don’t know why we saw a larger influence of supermarkets on the diets of black Americans compared to white Americans,” said Dr. Kimberly Morland of the Mt. Sinai School of Medicine. “Based on our previous research showing a lack of private transportation in predominately black neighborhoods, we suspect that white Americans may have a larger geographic area in which to select places to patronize.
“We believe these neighborhood differences may account in part for disparities in diet and illness.”
A report on the findings appears in the November issue of the American Journal of Public Health. Co-authors are Dr. Steven B. Wing, associate professor of epidemiology at UNC, and Ana Diez Roux, assistant professor of general medicine and epidemiology at Columbia University’s College of Physicians and Surgeons and Mailman School of Public Health.
The study relied on data generated by the UNC-based Atherosclerosis Risk in Communities Study, a large, long-term population-based investigation of hardening of the arteries with extensive information on subjects’ dietary intakes, among other characteristics, Morland said. Subjects lived in 208 U.S. neighborhoods, or “census tracts,” in Washington County, Md.; Forsyth Co., N.C.; Jackson, Miss.; and several Minneapolis suburbs.
Detailed information on the types and amounts of foods eaten from questionnaires completed by 10,623 study participants was used in the analysis, as were details about the availability of supermarkets, grocery stores and fast-food and full-service restaurants in the neighborhoods where they lived, she said.
Among the findings were that five times more supermarkets were located in census tracts where white participants lived compared to black participants, Morland said. Only 8 percent of the 2,392 black participants lived in a neighborhood with at least one supermarket as compared to 31 percent of whites.
“Even after controlling for education and income, a higher proportion of black Americans living in census tracts with at least one supermarket reported meeting dietary guidelines for fruits and vegetables than did black Americans living in census tracts with no supermarkets,” she said. “On average, the more supermarkets there were in a given area, the more likely residents were to meet dietary recommendations for fruits and vegetables. This was true for whites too, but the effect was weaker. We saw something similar with total fat and saturated fat intake.”
“Part of the significance of this study is that it promotes an environmental understanding of nutrition instead of just holding people responsible individually for what they eat,” said Wing, who was Morland’s adviser. “In some ways, we in public health have tended to blame the victim. This work shows that if you don’t live in an area where it’s possible to have easy access to reasonably priced, nutritious foods, then it’s not your fault that you’re not eating as healthfully as people are in other areas.”
Morland agreed. “This works shows that it’s important to consider the context in which people live and their physical environment in terms of their behaviors,” she said. “In the past, there has been a strong focus in public health in looking at behaviors without considering what it is like where people live day in and day out.
“Also, we see differences in health by race and by wealth all the time in public health studies. Looking at such structural features that are different between groups of people could be an important new avenue to consider when we’re looking at preventing disease.”
The relationship between diet and disease is well established, Morland said. Research has linked poor diets to cancer, diabetes, hypertension, birth defects and heart disease. Recommendations for healthier diets have spanned more than 40 years.