A systematic review of food composition tools used for determining dietary polyphenol intake in estimated intake studies

- US food composition databases are most common for analysis of phytochemical intakes.
- Case control studies use food frequency questionnaires for polyphenol analysis.
- Total isoflavones, flavonoids and lignans are the most commonly studied subclasses.
- Retention methods are used to expand existing food composition databases.

Translating food intake data into phytochemical outcomes is a crucial step in investigating potential health benefits. The aim of this review was to examine the tools for determining dietary-derived polyphenol intakes for estimated intake studies. Published studies from 2004 to 2014 reporting polyphenol food composition information were sourced with 157 studies included. Six polyphenol subclasses were identified. One quarter of studies (n = 39) reported total flavonoids intake with 27% reporting individual flavonoid compounds. Assessing multiple compounds was common with approximately 10% of studies assessing seven (n = 13), six (n = 12) and five (n = 14) subclasses of polyphenol. There was no pattern between reported flavonoids compounds and subclass studied. Approximately 60% of studies relied on publicly accessible food composition data to estimate dietary polyphenols intake with 33% using two or more tools. This review highlights the importance of publicly accessible composition databases for estimating polyphenol intake and provides a reference for tools available globally.