Dietary Polyphenol Intake Estimated by 7-Day Dietary Records among Japanese Male Workers: Evaluation of the Within- and Between-Individual Variation

抄録

Polyphenol intake has been estimated in some populations; however, information about day-to-day and individual differences in polyphenol intake has not been well-evaluated. In this study, we aimed to examine within- and between-individual variation in polyphenol intake in Japanese male workers. First, 56 male subjects (aged 37.9±10.4 y) completed detailed 7-d dietary records (DR). We then calculated their total polyphenol intake using our polyphenol content database and the within- and between-individual variations. We also estimated the minimum number of days of dietary assessment required both to rank individuals within a group and to assess an individual’s usual polyphenol intake with acceptable accuracy. The estimated daily total polyphenol intake was 965±471 mg/d, which was largely sourced from beverages. The day-to-day variation (CV_w) for polyphenol intake was 43.6%, and the variation between the individuals in the population (CV_b) for polyphenol intake was 45.9%. A 4-d DR was required to rank individuals within a group with high correlation coefficients (r=0.9), and a 19-d DR was required to assess the individual’s usual polyphenol intake with 20% deviation. The CV_w for polyphenol intake was intermediate between those of the other nutrients, but the CV_b for polyphenol intake was largest among the nutrients. These results suggest that the dietary intake of polyphenols should be carefully estimated considering its within- and between-individual variation.