Dietary Polyphenol Intake in US Adults and 10-Year Trends: 2007-2016

Background Polyphenols are a class of phytochemicals that have antioxidant, anti-inflammatory, anticancer, and antiviral properties. Previous research suggests that dietary polyphenol intake is protective against major chronic diseases. To our knowledge, no data on polyphenol intake for the US adult population are available. Objective This study explored usual dietary polyphenol intake among US adults in 2013-2016 and examined trends in intake during 2007-2016 by demographic characteristics, and identified major dietary sources of polyphenols. Design The National Health and Nutrition Examination Survey is a series of cross-sectional surveys representative of the civilian noninstitutionalized US population. Participants/setting This study included 9,773 adults aged 20 years and older. Main outcome measures Dietary and supplement data were obtained from two 24-hour dietary recalls. Polyphenol intake was estimated using the Phenol Explorer Database and adjusted for total energy intake. Statistical analysis performed Usual intake was estimated both overall and by demographic characteristics using the National Cancer Institute method. Trends in intake on a given day over 10 years were evaluated using regression analysis. The complex survey design was incorporated in all analyses. Results In 2013-2016, the usual intake of dietary polyphenols was a mean (standard error) of 884.1 (20.4) mg per 1,000 kcal/d. Polyphenol intake was higher in adults 40 years and older, women, non-Hispanic White adults, and college graduates. During 2007-2016, the mean daily polyphenol intake did not change significantly over time for overall and demographic groups. Main polyphenol classes consumed were phenolic acids (mean [standard error] of 1,005.6 [34.3] mg/d) and flavonoids (mean [standard error] of 379.1 [10.7] mg/d). Foods and beverages contributed 99.8% of polyphenol intake, with coffee (39.6%), beans (9.8%), and tea (7.6%) as major dietary contributors. Conclusion Findings from this study suggest that polyphenol intake is consistent with the low intake of fruits, vegetables, and whole grains in the US population, and provide more evidence of the need for increased consumption of these food groups.