Use and Evaluation of the Nutrient Density Concept for Assessing the Impact of Socioeconomic Factors on Nutritional Quality of Diets

Data from 7285 individual participants in the USDA Spring Nationwide Food Consumption Survey were analyzed using the nutrient density concept and multiple regression procedures to evaluate the impact of socioeconomic status on the nutritional quality of foods consumed. For each socioeconomic group the average daily amount of nutrients consumed per 1000 kcal of food consumed were computed and compared with the Recommended Dietary Allowances which had been converted to single-value nutrient allowances per 1000 kcal. This nutrient density approach identified qualitative patterns of food consumption for selected income, region, urbanization, household size, race, employment and education groups as well as indicating the degree to which these groups met the RDA. Results demonstrated that socioeconomic status had relatively little impact upon the average nutrient density of diets consumed by the population. Income level had no statistically significant effect upon the nutritional quality of diets for any of the fourteen nutrients studied. Household size affected nutrient density consumption of fat, carbohydrate, vitamin s6 and vitamin C. Race affected calcium, magnesium, vitamin A and thiamin density of diets. Other socioeconomic factors were significantly related to only one or two nutrients. The differences in average nutrient density of diets resulted from differences in the quality of foods consumed from the Basic Four (nutrient-dense) Plus One (calorie-dense) food groups and not from differences in the percent contribution of these two food groups to nutrient intake per 1000 kcal. Average diets for all socioeconomic groups were below nutrient density standards for calcium, iron, magnesium, vitamin B6 and carbohydrate. There was also a high frequency of individuals with vitamins A and vitamin C intakes below nutrient density standards despite adequate group mean intakes per 1000 kcal for these nutrients. Results supported the hypothesis that, regardless of socioeconomic status, Americans consume diets that average very similar nutrient content per energy unit. This type of information contributes to a better understanding of dietary habits of Americans and provides a meaningful framework from which to establish guidelines for government agencies, nutrition educators and the food industry