Association of the neighborhood retail food environment with sodium and potassium intake among US adults.

Introduction: High sodium intake and low potassium intake, which can contribute to hypertension and risk of cardiovascular disease, may be related to the availability of healthful food in neighborhood stores. Despite evidence linking food environment with diet quality, this relationship has not been evaluated in the United States. The modified retail food environment index (mRFEI) provides a composite measure of the retail food environment and represents the percentage of healthful-food vendors within a 0.5 mile buffer of a census tract.

Methods: We analyzed data from 8,779 participants in the National Health and Nutrition Examination Survey, 2005-2008. By using linear regression, we assessed the relationship between mRFEI and sodium intake, potassium intake, and the sodium-potassium ratio. Models were stratified by region (South and non-South) and included participant and neighborhood characteristics.

Results: In the non-South region, higher mRFEI scores (indicating a more healthful food environment) were not associated with sodium intake, were positively associated with potassium intake (P [trend] = .005), and were negatively associated with the sodium-potassium ratio (P [trend] = .02); these associations diminished when neighborhood characteristics were included, but remained close to statistical significance for potassium intake (P [trend] = .05) and sodium-potassium ratio (P [trend] = .07). In the South, mRFEI scores were not associated with sodium intake, were negatively associated with potassium intake (P [trend] = < .001), and were positively associated with sodium-potassium ratio (P [trend] = .01). These associations also diminished after controlling for neighborhood characteristics for both potassium intake (P [trend] = .03) and sodium-potassium ratio (P [trend] = .40).

Conclusion: We found no association between mRFEI and sodium intake. The association between mRFEI and potassium intake and the sodium-potassium ratio varied by region. National strategies to reduce sodium in the food supply may be most effective to reduce sodium intake. Strategies aimed at the local level should consider regional context and neighborhood characteristics.