Trends in black-white differentials in dietary intakes of U.S. adults, 1971-2002

Abstract

Background: Disparities in the health status of blacks and whites have persisted despite considerable gains in improved health of the U.S. population. Tracking changes in black-white differentials in dietary attributes over time may help in understanding the contribution of diet to these disparities.

Methods: Data were used from four National Health and Nutrition Examination Surveys conducted between 1971 and 2002 for trends in self-reported intakes of energy, macronutrients, micronutrients, fruits and vegetables, and the energy density of foods among U.S. non-Hispanic black (n=7099) and white (n=23,314) men and women aged 25 to 74 years. Logistic and linear regression methods were used to adjust for multiple covariates and survey design.

Results: Energy intake, amount of food, and carbohydrate energy increased, whereas percentage of energy from protein, fat, and saturated fat decreased over time in all race and gender groups (p<0.001). In whites and in black women, energy density increased (p<0.001) in parallel to increases in obesity prevalence. In all surveys, black men and women reported lower intakes of vegetables, potassium, and calcium (p<0.001) than their white counterparts. In men, the race differential in calcium intake increased across surveys (p=0.004).

Conclusions: Dietary intake trends in blacks and whites from 1971 to 2002 were similar, which suggests that previously identified dietary risk factors that differentially affect black Americans have not improved in a relative sense.

Figure 1

Secular trends in the prevalence of obesity and mean energy density of foods and nutritive beverages among men and women (NHANES I, 1971–75 to NHANES 1999–2002).

Figure 2

Multivariate-adjusted intakes of potassium (top row; mean intake), calcium (middle row; mean intake), and vegetables (bottom row; percent reporting any vegetable) for non-Hispanic white (solid line) and black (dotted line) adults by education and poverty level (all surveys combined). All education trends were significant for NH whites and blacks. Poverty level trends were significant for potassium and vegetable intake. All race differentials were significant for all categories of education and poverty.