Dietary intake of polyphenolic compoundsfrom major food groups: results of analytical determinations

Polyphenols are widely distributed in plants and plant-based foods. Although they are not considered essential nutrients, they exhibit a broad spectrum of biological properties, particularly antioxidant activity. The aim of this study was to evaluate dietary intake of polyphenolic compounds derived from major food groups among young Polish adults. Dietary intake was assessed using a 24-hour dietary recall method supported by dedicated computer software. Liquid chromatography-mass spectrometry (LC-MS) was applied to identify major polyphenolic compounds, while the Folin-Ciocalteu assay and the DPPH radical scavenging test were used to evaluate the antioxidant activity of basic food groups. The primary sources of polyphenolic compounds were fruits, vegetables, and, most notably, beverages – mainly tea – which accounted for over 65% of beverage consumption in both interviewed groups. The predominant phenolic compounds identified were gallic acid, epigallocatechin gallate (EGCG), quercetin, and rutin. Gallic acid was the main polyphenolic component in daily food rations, with beverages constituting its primary dietary source. Only trace amounts of polyphenols were detected in eggs, fish, oils, milk, and meat products. The antioxidant activity of female diets (682.6 mg GAEq) was slightly higher compared with male food rations (680.04 mg GAEq).