Fruits and vegetables damage DNA
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LinksGreen tea extract only affects markers of oxidative status
postprandially: lasting antioxidant effect of flavonoid-free diet.
Young JF, Dragstedt LO, Haraldsdóttir J, Daneshvar B, Kall MA, Loft S,
Nilsson L, Nielsen SE, Mayer B, Skibsted LH, Huynh-Ba T, Hermetter A,
Sandström B.
Research Department of Human Nutrition, Royal Veterinary and
Agricultural University, Frederiksberg, Denmark.
Epidemiological studies suggest that foods rich in flavonoids might
reduce the risk of cardiovascular disease and cancer. The objective of
the present study was to investigate the effect of green tea extract
(GTE) used as a food antioxidant on markers of oxidative status after
dietary depletion of flavonoids and catechins. The study was designed
as a 2 x 3 weeks blinded human cross-over intervention study (eight
smokers, eight non-smokers) with GTE corresponding to a daily intake
of 18.6 mg catechins/d. The GTE was incorporated into meat patties and
consumed with a strictly controlled diet otherwise low in flavonoids.
GTE intervention increased plasma antioxidant capacity from 1.35 to
1.56 (P<0.02) in postprandially collected plasma, most prominently in
smokers. The intervention did not significantly affect markers in
fasting blood samples, including plasma or haemoglobin protein
oxidation, plasma oxidation lagtime, or activities of the erythrocyte
superoxide dismutase, glutathione peroxidase, glutathione reductase
and catalase. Neither were fasting plasma triacylglycerol,
cholesterol, alpha-tocopherol, retinol, beta-carotene, or ascorbic
acid affected by intervention. Urinary 8-oxo-deoxyguanosine excretion
was also unaffected. Catechins from the extract were excreted into
urine with a half-life of less than 2 h in accordance with the short-
term effects on plasma antioxidant capacity. Since no long-term
effects of GTE were observed, the study essentially served as a fruit
and vegetables depletion study. The overall effect of the 10-week
period without dietary fruits and vegetables was a decrease in
oxidative damage to DNA, blood proteins, and plasma lipids,
concomitantly with marked changes in antioxidative defence.
PMID: 12064344
"fruit and vegetables depletion ... decrease in oxidative damage to
DNA" - fructose to be blamed here??
Taka