Objective: We hypothesized an association between physiological amounts of different classes and subclasses of polyphenol from a subject's regular diet and lipid peroxidation.
Subjects and methods: Diet was assessed through direct observation and a semiquantitative food frequency questionnaire. Daily polyphenol intake, total as well as subgroups, and plasma malondialdehyde (MDA) were determined together with other variables used as covariates (age, sex, energy intake, Quetelet index, plasma glucose, cholesterol and triglycerides, and tobacco use) in 159 institutionalized elderly subjects (68 men, 91 women) with a mean age of 73.1 years.
Results: Flavonoid intake was inversely associated with MDA in a multiple regression analysis. The potential effect of flavonoids was mainly ascribed to flavanols. A diet score based on the 5 dietary components previously identified as the major contributors to the intake of flavanols was developed. None of the food components was associated with MDA individually, but the overall diet score was inversely associated in a logistic regression analysis.
Conclusions: This study represents one of the few attempts to date to evaluate the impact of phenol intake on oxidative damage. Flavonoids intake must be promoted to reduce the negative health effects of oxidative stress in elderly people.