Dietary intake of polyphenols and major food sources in an institutionalised elderly population

Polyphenols are bioactive compounds widely found in fruit, vegetables and beverages of plant origin. Epidemiological studies have suggested an association between polyphenol intake and health; antioxidant, anti-inflammatory, anti-carcinogenic and other bioactivities may contribute to these beneficially protective effects. To date, most epidemiological studies describing polyphenol intake have been limited by the information available in nutrient databases. The present study aimed to determine the total and individual polyphenol intake among institutionalised elderly people living in Asturias (North of Spain) and to identify the major dietary sources of polyphenol classes and subclasses.

The study sample comprised 304 subjects with a mean age of 73.2 years for men and 76.8 years for women. Dietary intake was assessed by means of a food frequency questionnaire. Phenol content was estimated from the Phenol-Explorer database, as developed at the French National Institute for Agricultural Research. The contribution of each food to the total and subgroup intake of polyphenols was calculated as a percentage.

Except for flavonones, total polyphenol intake, groups and subgroups, was higher in men than women. The main polyphenol groups contributing to total polyphenol intake were flavonoids (62%) and phenolic acids (35.5%). We identified red wine, coffee, apples, oranges and green beans as the major food sources providing total polyphenol intake. Flavonoid and lignan intake was lower for those aged >80 years. Smoking habit, red wine consumption, physical activity and a Mediterranean diet score were associated with a greater polyphenol intake.

The present study provides information on polyphenol intake in an elderly Mediterranean population with a level of detail that has not been achieved previously. The identification of age and lifestyle factors associated with the intake of polyphenols may be useful in future studies regarding polyphenols.