Healthy eating index scores are associated with blood nutrient concentrations in the third national health and nutrition examination survey.

OBJECTIVES: The Healthy Eating Index (HEI) is a summary measure of dietary quality, based on a 100-point scale. Our objectives were to assess the HEI as a measure of dietary status through its correlation with nutritional biomarkers and to identify those biomarkers most associated with diet quality and healthful food intake patterns. DESIGN: National Health and Nutrition Examination Survey (NHANES) III, 1988-94. SUBJECTS: Adults (> or =17 years) with calculated HEI scores and blood nutrient data (n=16,467). STATISTICAL ANALYSES PERFORMED: Weighted crude and partial Pearson correlation coefficients (r) between HEI scores and blood nutrients were calculated. Geometric mean blood nutrient concentrations were calculated for five HEI score categories (ranging from 80). RESULTS: HEI score was positively correlated with serum (r=0.25) and red blood cell (r=0.27) folate, serum vitamins C (r=0.30) and E (r=0.21), and all serum carotenoids except lycopene (r=0.17 to 0.27). These blood nutrient concentrations were 21% to 175% higher for participants in the highest HEI score group (>80) compared with those in the lowest group (< or =50). Mean HEI scores were significantly (P<.0001) greater among the 42% of participants who took dietary supplements. Most correlations were attenuated when adjusted for additional factors. CONCLUSIONS: HEI score is correlated with a wide range of blood nutrients; the strongest relationships are with biomarkers of fruit and vegetable intake. These results are an important step in the validation of the HEI, emphasizing its potential as a tool for nutrition and health studies.