Diet diversity and nutrient intake.

Variety is espoused as a key to dietary adequacy, yet data from new shortcut dietary measures suggest that intakes of relatively few foods can accurately classify individuals according to nutrient intake. This study examines diet diversity, caloric intake, and nutrient density values as contributors to the level of selected nutrients in the diets of 1,747 white men and 1,898 white women, 18 to 34 years old, completing the 24-hour recall in NHANES II. Nutrient intake was directly related to both number of foods eaten and total calories consumed, as well as to nutrient density values. For fat, saturated fat, and potassium, higher caloric consumption alone may account for substantial differences in nutrient intakes between the lowest and highest quartiles. For cholesterol, calcium, and vitamin A, differences in dietary density were more important in explaining nutrient intake differences. Both caloric intake and nutrient density influence sodium intake from food sources. For some nutrients, an overall measure of diversity may be useful for estimating intakes. For others, nutrient-specific diversity indexes would likely be needed. Knowledge of specific foods in diets with high levels of nutrients could aid the construction of food frequency instruments.