Whole-grain food intake among US adults, based on different definitions of whole-grain foods, NHANES 2003-2018

Background Whole-grain (WG) foods are defined by the Dietary Guidelines for Americans (DGA), FDA, AHA, American Association of Cereal Chemists International (AACCI), and Whole Grains Council (WGC) in different ways with diverse focuses on grain components only, whole foods, or nutrient contents. Objectives We aimed to compare estimated WG food intake among US adults using different definitions. Methods For each definition, we estimated the mean intake and trends of WG food consumption using survey-weighted 24-h dietary recalls from nationally representative samples of 39,755 US adults aged 20+ y from 8 cycles (2003-2018) of the NHANES. This is an observational study that used deidentified and publicly available datasets. Results The estimated mean consumption of WG foods (ounces equivalents/2000 kcal/d, oz. eq./d) varied by definition. In 2017-2018, the AHA (mean [SEM]: 1.05 [0.07] oz. eq./d) and WGC (0.95 [0.07]) definitions yielded the highest amounts, followed by the DGA (0.81 [0.06]), AACCI (0.73 [0.05]), and FDA (0.53 [0.04]). Using all definitions except for WGC, US adults increased WG food intake from 2003-2004 to 2017-2018 with the largest increase (61.5%) using the AHA (from 0.65 to 1.05 oz. eq./d), followed by DGA (0.50 to 0.81) and AACCI (0.51 to 0.73) definitions. For each definition, the main sources of WG foods consumed by US adults were ready-to-eat cereals, cooked grains and cereals, and breads (including rolls and tortillas). For all definitions except the AHA, non-Hispanic White adults and individuals with college degrees or above consumed higher levels of WG foods than non-Hispanic Blacks and those with lower levels of education. Conclusions Different definitions affect the determination of WG foods, estimated intakes, and associated trends in WG food consumption among US adults. These findings call for a standardized definition of WG foods to guide consumers, industry, and policymakers in promoting WG intake in the US. Clinical Trial Registration: Not Applicable.