Biology Reference
In-Depth Information
on ellagitannins (as ellagic acid equivalents) in selected foods consumed
in Finland (Koponen
et al.
, 2007) and food consumption data from 48-
hour dietary recalls of 2007 adults of the FINDIET 2002 Study. The
dietary intake of ellagitannins and free ellagic acid derivatives was 12
mg/day (women 15, men 8 mg/day), of which 99% was obtained from
berries and berry dishes (Ovaskainen
et al
., 2008).
8.4 Potential Health Benefits of Foods Rich in Ellagitannins
Several biological activities and health-related properties have been
reported for ellagitannin-containing foods, suggesting that they could
provide protection against,
e.g
., oxidative stress, pathogenic bacteria and
cancer. Although these properties may be attributed to their high content
of ellagitannins, these foods also contain a variety of other polyphenolic
compounds as well as common nutrients, which probably contribute to
these bioactivities.
8.4.1 Antioxidant activity
Oxidative stress is caused by imbalance between production of free
radicals and the body's antioxidation system, and has been implicated in
the pathogenesis of many human diseases. Antioxidants can terminate
free radical chain reactions by removing radical intermediates, or they
can slow or prevent oxidation of other compounds,
e.g.
, lipids, proteins
or DNA, by being oxidized themselves. Antioxidant activity is the most
well-known bioactive property of polyphenols and polyphenol-rich
foods.
Antioxidant activities of food extracts rich in ellagitannins have been
determined by using various
in vitro
assays, and the high activities of
strawberries (Meyers
et al.
, 2003, Aaby
et al.
, 2005, 2007), raspberries
(Liu
et al.
,
2002, Beekwilder
et al.
, 2005), cloudberries (Kähkönen
et al.
,
2001) and other
Rubus
berries (Wada and Ou, 2002), pomegranates (Gil
et al.
, 2000) and walnuts (Anderson
et al.
, 2001) and their ellagitannins
have been extensively reported. These foods also rank high when
compared to other plant-based foods.
