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Free oxygen radicals
appear to be involved in several pathologic conditions such
as:
- Development
of hardening of the arteries
- Different stages
of cancer development
- Autoimmune destruction
of ß cells in the pancreas leading to diabetes
- Mediators of
inflammatory damage in asthma and in joints in rheumatoid
arthritis
- Process leading
to cataracts
Flavonoids are
products of plant metabolism and have different phenolic (benzene-type
ring) structures. They are effective antioxidants because
of their free radical scavenging properties and because they
are chelators of metal ions thus, they may protect tissues
against free oxygen radicals and fat oxidation. Because of
differences in their chemical structure, bioavailability,
distribution, and metabolism, different flavonoid compounds
may have different effects on human health.
A study of over
10,000 people found that those consuming fruits and vegetables
rich in different flavonoids have a reduced risk of overall
mortality and of several chronic diseases.
What do flavonoids
do?
Flavonoids, which
are found in a variety of fruits and vegetables as well as
in tea and red wine, are thought to boost health in part by
combating oxidation, a process in which cell-damaging substances
called free radicals accumulate.
How was the
study conducted?
Participants filled
out a questionnaire and completed an interview to find out
what they had eaten during the previous year. Based on average
flavonoid contents of foods available in the study area, the
researchers estimated each person's flavonoid intake. The
researchers tracked the development of disease in the participants
for up to 28 years after the initial interview.
What did the
study show?
The results of
our study suggest the presence of a protective association
between flavonoid intake and subsequent occurrence of heart
disease, stroke, lung and prostate cancer, type 2 diabetes,
and asthma.
What flavonoids
were the most effective?
For instance, greater
consumption of apples, a main source of quercetin in the study
area, and onions, which contain a flavonoid called kaempferol,
were both linked to a reduced risk of dying from heart disease.
Myricetin, hesperitin, and naringenin were also found to be
useful. A lifestyle associated with a high intake of foodstuffs
rich in flavonoids appears to reduce the risk of chronic diseases.
American
Journal of Clinical Nutrition September 2002;76:560-568
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