Green tea has cholesterol-lowering effect
MedWire News: Consumption of green tea may have a beneficial effect on levels of total and low-density lipoprotein (LDL) cholesterol, suggest study findings.
The results arise from a systematic review and meta-analysis of randomized controlled trials evaluating the relationship between green tea catechins and serum lipid levels.
Catechins comprise 80-90% of the polyphenols found in green tea, explain Olivia Phung (Western University of Health Sciences, Pomona, California, USA) and team in the Journal of the American Dietetic Association.
However previous studies have demonstrated conflicting results about the lipid-lowering effects of green tea catechins, they add.
Phung and co-authors therefore performed a systematic literature search and selected 20 trials involving 1415 individuals that evaluated the use of green tea catechins in any dose or form, including extract tablets/capsules, powders, or beverages, and reported data on at least one serum lipid level (total, LDL, high-density lipoprotein [HDL] cholesterol, or triglycerides).
The duration of study ranged from 3-24 weeks and dose of green tea catechins ranged from 145-3000 mg per day.
The team found that consumption of green tea catechins was associated with a significant 5.46 and 5.30 mg/dL (0.140 and 0.138 mmol/L) reduction in total and LDL cholesterol, respectively, compared with control. There were no significant effects on HDL cholesterol or triglycerides.
Subgroup analysis of catechin dose suggested that effects were seen with higher doses and not lower doses, report the researchers. However, a dose-response relationship could not be assessed.
"Future studies should be conducted to determine the ideal dose and duration of green tea catechins," they write. In addition, the team suggests that the effect of specific catechin components should be investigated because there "may be an additive or synergistic effect on lipid values."
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By Nikki Withers