Validation of the healthy eating index with use of plasma biomarkers in a clinical sample of women

Abstract

Background: The Healthy Eating Index (HEI) is a 100-point analytic scoring tool used to measure compliance with dietary recommendations and guidelines. Objective: The objective was to calculate HEI scores for a sample of women and to link the HEI scores to plasma biomarkers of dietary exposure. Design: Respondents were 340 women aged 21-80 y who were enrolled in a case-control study of diet and breast cancer. The sample included 172 patients with newly diagnosed cancer (case subjects), 149 cancer-free control subjects, and 19 women at high risk of breast cancer. Dietary intake assessment was based on 3-d food records. HEI scores were calculated for all respondents. Venous blood was collected for measurements of plasma carotenoids, vitamin C, and folate. Results: Higher HEI scores were associated most strongly with greater dietary variety (r=0.71), higher intakes of fruit (r=0.57), and lower intakes of fat and saturated fat. HEI scores were also associated with higher intakes of energy, carbohydrates, fiber, folate, and vitamin C. Higher HEI scores were associated with higher plasma concentrations of α-carotene (r=0.40), β-carotene (r=0.28), β-cryptoxanthin (r=0.41), lutein (r=0.23), and vitamin C (r=0.26) after age and vitamin supplement use were controlled for in a regression model. There was a further association between HEI scores and socioeconomic variables. Women with higher HEI scores were more likely to be older, married, and better educated and to have higher household incomes. Conclusions: The HEI is a useful tool for describing the overall diet pattern and represents a promising new tool for nutritional epidemiology. Diet quality, as defined by the HEI, varies with age and socioeconomic status.