Integrating national and international databases to enhance polyphenol intake estimates and their association with the consumption of unprocessed or minimally processed foods and ultra-processed foods

Polyphenols are bioactive compounds associated with lower risks of noncommunicable diseases. However, accurately estimating dietary polyphenol intake remains challenging, as single databases often introduce systematic bias. This study compared flavonoid content between the Brazilian Food Composition Table (TBCA) and the Phenol-Explorer database. Using three approaches (integrated databases, TBCA alone, and Phenol-Explorer alone), we estimated flavonoids, non-flavonoids, and total polyphenols intakes in the Brazilian population. Dietary intake data from 46,164 individuals, assessed using two 24-hour recalls, were linked to both databases. Associations between polyphenol intake and unprocessed or minimally processed foods (UMPF) and ultra-processed foods (UPF) were evaluated. The integrated approach estimated a mean total flavonoid intake of 107.36 mg/day (95%CI: 104.82–109.90). Compared with this reference, Phenol-Explorer alone estimated a higher intake (140.26 mg/day; 95%CI: 137.45–143.06), while TBCA estimated a lower intake (22.71 mg/day; 95%CI: 22.19–23.22). Mean total daily polyphenol intake was 419.03 mg/1000 kcal (95%CI: 414.20–423.8), with phenolic acids comprising 83.5% of the total. Total polyphenol intake was positively associated with UMPF consumption and inversely associated with UPF consumption. Integrating databases yields more refined and representative estimates of polyphenol intake in the Brazilian context.