Green tea protection from linoleic acid limited
Taka
LinksGreen tea extract decreases plasma malondialdehyde concentration
but does not affect other indicators of oxidative stress, nitric oxide
production, or hemostatic factors during a high-linoleic acid diet in
healthy females.
Freese R, Basu S, Hietanen E, Nair J, Nakachi K, Bartsch H, Mutanen M.
Division of Nutrition, University of Helsinki, Finland.
BACKGROUND: Green tea contains polyphenolic catechins which can act as
antioxidants and thus decrease the risk for cardiovascular diseases.
AIM OF THE STUDY: To investigate whether green tea extract differs
from placebo in its effects on markers of antioxidant status, lipid
peroxidation, nitric oxide production, thromboxane production, and
blood coagulation during a controlled high linoleic acid diet in
healthy subjects. METHODS: Twenty healthy non-smoking females (23-50
years) participated in a 4-week controlled intervention study. The
experimental diet was rich in linoleic acid (9 en%) and contained fat,
protein, and carbohydrates: 27, 14, and 59 en%, respectively. In
addition, the subjects ingested encapsulated green tea extract (3 g/d)
or placebo mixture in a double-blind manner. Fasting blood samples and
five 24-hour urines were collected before and at the end of the 4-week
experimental period. Same samples were received from 10 control
subjects. RESULTS: Green tea extract significantly decreased plasma
malondialdehyde (MDA) concentration in comparison with the placebo
treatment. The treatments did not differ in serum lipids, indicators
of antioxidant status, urinary 8-isoprostaglandin F2 alpha, 2,3-
dinorthromboxane B2, nitric oxide metabolites or coagulation
indicators. CONCLUSIONS: We conclude that an amount of green tea
extract which corresponds to 10 cups of tea per day for 4 weeks does
not have specific effects on several indicators related to risk of
cardiovascular diseases in comparison with placebo treatment. The
relatively small but significant decrease in lipid peroxidation
indicated by decreased plasma MDA was not associated with changes in
markers of oxidative stress (urinary 8-isoprostaglandin F2 alpha and
blood oxidized glutathione) or hemostasis.
PMID: 10443337