Income and racial patterns of dietary vitamin C intake among black and white girls.

The authors examined the influence of income and race on mean dietary vitamin C intake and the risk of dietary vitamin C intake at levels below the recommended dietary allowance (RDA). They performed a cross-sectional analysis of 2,032 black and white 9- and 10-year-old females, from a wide range of income groups, who participated in the National Heart, Lung, and Blood Institute Growth and Health Study. Mean intake of vitamin C, exclusive of vitamin supplements and determined by 3-day diet records, exceeded the RDA of 45 milligrams per day for that age group in all racial and income categories. The investigators found that annual household income was directly associated with mean dietary vitamin C intake (P < 0.0001) and that blacks had higher mean dietary vitamin C intakes than whites (P < 0.01). Among both blacks and whites, household income and risk of below-RDA vitamin C intake were inversely correlated, but this trend was statistically significant for blacks only (P < 0.05). Except for the lowest level income group (less than $10,000 per year), black girls from households with incomes less than $30,000 per year were at increased risk for below-RDA vitamin C intake (relative risk = 1.93 in the $10,000-$19,999 per year group and 1.63 in the $20,000-29,999 per year group, P < 0.05), compared with black girls in the highest income category. One-quarter of white girls overall and more than 30 percent of white girls in the lowest two income groups had below-RDA vitamin C intakes. If the findings are generalizable,they underscore the importance of public health programs to address the adequacy of dietary vitamin C intake among preadolescent black and white females.