Background: Many studies have examined rapidly changing trends in U.S. dietary intake, but not as they correspond to other health inequalities among black and white Americans. The purpose of this study was to explore 30-year trends in diet quality and to examine whether income or education is the key socioeconomic factor linked with these shifts.
Methods: The 1965 Nationwide Food Consumption Survey and the 1994-1996 Continuing Survey of Food Intake by Individuals were used and included, respectively, 6476 and 9241 respondents who were aged > or =18 years. The Revised Diet Quality Index (DQI-R), an instrument that provides a summary assessment of a diet's overall healthfulness, was also used.
Results: Between 1965 and 1996, improvements were found in both the overall DQI-R and its components across all education levels, with the exception of calcium intake. Conversely, improvements linked with income effects were inconsistent and less clear. In 1965, the effect of college attendance resulted in a 1.8 point higher DQI-R, higher calcium intake, and increased servings of fruits and vegetables. In 1994-1996, there were consistently improved diets for the overall DQI-R and its components, particularly among college attendees.
Conclusions: Diet quality has improved across both race and socioeconomic status groupings between 1965 and 1994-1996; however, education provides a much clearer differentiation. Education efforts must be emphasized to eliminate disadvantages in diet quality.