Candidate measures of whole plant food intake are related to biomarkers of nutrition and health in the US population (National Health and Nutrition Examination Survey 1999-2002)

Indices of overall dietary patterns are used in epidemiologic research to examine the relationship between nutrition and health. The objective of this study was to develop and validate an interpretable summary measure of dietary intake of whole plant foods (WPF; whole grains, vegetables, whole fruit, legumes, nuts, seeds) because of their similar nutritional characteristics and health effects. Six candidate WPF measures were calculated using data from subjects (age ≥6 years) participating in the 1999-2000 and 2001-2002 National Health and Nutrition Examination Survey. Measures differed by the inclusion or exclusion of potatoes and whether they were expressed as total intake or as a proportion of energy (4180 kJ) or mass (kg) consumed. Both standard and nontruncated (allowed to vary proportionally with intake) Healthy Eating Index-2005 (HEI-2005) scores were calculated. Regression analysis examined the associations between WPF and HEI-2005 measures, and between all diet measures and serum carotenoid concentration, serum lipids, fasting glucose, insulin, C-peptide, and C-reactive protein. Mean total WPF intake was 3.6 cup/oz equivalents, or 1.7 cup/oz equivalents per 4180 kJ and per kg. The largest R2 between WPF and HEI-2005 measures was found for energy-adjusted WPF including potatoes and nontruncated HEI-2005 (R2 = 0.50). All diet measures were positively related to serum carotenoids (P <.001) and were similarly related to health indicators (R2 range from 0.003 to 0.16, P <.045 for regressions, indicating significant associations between WPF measures and health indicators). Whole plant food measures are interpretable indicators of dietary intake that are significantly related to nutrition and health biomarkers and may be of public health use.