Diet quality, diet cost and household income

Abstract

Energy-dense, nutrient-poor diets are disproportionately consumed by low-income populations. This bias might be due to the fact that high energy density (ED) foods provide dietary energy more cheaply than low ED foods. The hypothesis that diet cost is a key variable linking low income to low diet quality the has been difficult to test in part because existing data sources do not provide diet quality measures, diet cost and income data for the same individuals. We explored the association between diet quality, diet cost and household income in a sample of 160 adult men and women with mean age 40y and median household income $55–$64.9k. Subjects’ dietary intakes were assessed using a novel food-frequency questionnaire-based instrument that yields estimated daily diet costs in addition to standard estimates of nutrient and energy intakes. Household income was reported in a separate demographic questionnaire. Dietary ED was calculated by dividing dietary energy by total weight of food consumed. Analyses of variance revealed that the lowest quintile of diet cost was associated with significantly higher dietary ED. Additionally, lowest household incomes were significantly associated with higher dietary ED. These findings support the hypothesis that incomes and food prices are key factors influencing the diet quality of individuals. Supported by USDA CSREES grant 2004-35215-14441 and NIDCR fellowship T32 DE07132 to PM