The average flavonoid intake varied in the 16 cohorts of the Seven Countries Study between <10 mg/day in the rural Finnish and >60 mg/day in the rural Japanese cohorts. After 25 years of follow-up, the CHD mortality rate was 6 times higher among farmers from Eastern Finland compared to those in Japan. The average cohort flavonoid intake was significantly inversely associated with 25-year CHD mortality rates.

High cohort flavonoid intake related to low CHD mortality rates.

The intake of flavonoids

Information on the average food intake of the 16 cohorts was obtained in the 1960s, and the average flavonoid intake was determined chemically in representative food composites. The most common flavonoid measured was quercetin. Flavonoids, an extended class of chemically related compounds ubiquitously present in plant foods. In a range of experimental models, these compounds have demonstrated biological effects, which may partially explain the beneficial health effects of a diet high in vegetables and fruits. Flavonoids are present in tea, apples, onions and red wine. High intakes were observed in Japan due to high consumption of tea, in Slavonia (Croatia) due to a high intake of onions and in Dalmatia (Croatia) because of a high intake of red wine.