Washington: The first human study testing theaflavin-enriched green tea has found that a tea product comprising green and black tea extracts effectively lowers cholesterol levels in people.

The study included 240 men and women with high cholesterol levels in China. During the 12-week trial, participants, already on a low-fat diet, were randomly chosen to receive either a placebo or a 375 mg soft gel capsule containing green and black tea extracts enriched with the antioxidant theaflavin.

"Personally, I was very surprised. I expected, if anything, a very slight cholesterol-lowering effect. But what we saw was a 16 per cent reduction in low density lipoprotein (LDL) cholesterol," said lead author Dr David J Maron, associate professor of medicine at Vanderbilt University Medical Centre.

Tea is the second most widely consumed beverage worldwide. In the past, several epidemiological studies had shown that tea consumption is associated with lower cholesterol. Experiments in animals have demonstrated that green tea, black tea and flavonoids derived from green and black tea lowers cholesterol.

However, previous tea-drinking experiments in humans, as well as those experiments involving the administration of green tea extract, have failed to show any effects on cholesterol.

The 375 mg capsule used in this study is an extract made up of 75 mg of theaflavins (flavonoids from black tea), 150 mg of catechins (flavonoids from green tea) and 150 mg of other tea antioxidants called polyphenols. It is equivalent to 35 cups of high-quality black tea and seven cups of green tea.

Maron said there is a need to identify additional non-drug options for lowering cholesterol that have sufficient safety and efficacy data. There is also a need to find products that are more practical for the consumer than viscous fibre and foods made with plant stanols.

While pleased with the initial outcomes, he recommends further testing to determine long-term safety, the effective dosing range, the impact when the extract is taken with lipid medication (especially statins) and the adaptability to other ethnic and patient groups.

ANI