A new analysis of published studies that green tea is consumed, either as a beverage or in capsule form, is linked to a significant reduction, but modest in total and LDL or "bad" cholesterol, but researchers found no association with HDL or "good" cholesterol and triglycerides.
Green tea contains catechins, polyphenolic compounds known to exert several protective effects, especially in the cardiovascular system.
However, Phung and colleagues note that although randomized controlled trials have examined the effect of green tea catechins in blood fats, or lipids, including cholesterol, these have been small and showed conflicting results.
They decided to pool and analyze the evidence so far of all the studies that found that examined the relationship between consumption of green tea catechins and changes in levels of total, low density lipoprotein (LDL), lipoprotein high density (HDL) cholesterol and triglycerides.
We searched all known databases to March 2010 and found 20 randomized controlled trials with a total of 1,415 participants who reported changes in at least one of these levels.
Analyzed the data from these trials, they found that:
- Green tea catechins, at doses ranging from 145 to 3,000 mg per day (including consumption as green tea beverage and extract in capsules) taken for 3 to 24 weeks, led to statistically significant reductions in total and LDL ("bad") cholesterol compared to controls who did not consume any.
- Green tea catechins did not alter HDL ("good") cholesterol or triglyceride levels.
The results showed that the shape of drinking green tea was more effective than capsules consistently, despite the overall benefits were quite small, Phung told Reuters in an e-mail that urged patients already taking cholesterol-lowering drugs not to change to green tea, either in capsules or drink.
