FRUIT SOURCE AND STRUCTURAL FACTORS INFLUENCE THE
METABOLISM OF PROANTHOCYANIDINS IN THE INTESTINE
In the large intestine, proanthocyanidins (PAs) are
converted by bacteria into compounds that are more readily absorbed. A
team of scientists at VTT, Finland, have studied the mechanisms by which
this process takes place. The effects of the intestinal bacteria on PAs
and the(+)-catechin and (-)-epicatechin units from which these are
formed, are studied in an in vitro (test-tube) model using
extracts from grapes and apples. The study has shown that both fruit
source and structural factors influence this microbial metabolism.
Proanthocyanidins (PAs), unlike most other nutrients,
have been shown to be very poorly absorbed from the gut. After
consumption, the PAs continue their journey along the digestive tract to
the large intestine and are subjected to the intestinal microflora,
which converts and metabolizes them into compounds that are more readily
absorbed. Therefore, their health benefits are likely to be a result of
smaller compounds derived from them.
The health benefits of a flavonoid-rich diet are
widely recognized. There have been many studies focusing on the
relationship between the consumption of flavonoid-rich foods and the
occurrence of major chronic diseases, such as cardiovascular disease and
some cancers. These associations have been investigated using evidence
from population-based studies, animal studies and in vitro
(test-tube) studies. These in vitro studies aim at investigating
different mechanisms of flavonoid metabolism outside the human body.
However, these studies do not replace studies in a living body, but they
help in understanding the phenomena occurring in the intestine.
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