Green tea (or those who sell it) boasts a healthful reputation, but scientific evidence supporting the claims has been mixed at best. Recently, however, US researchers working with investigators in China report that a green tea extract - in capsule form - has a beneficial effect on cholesterol levels. Their findings are published in the Archives of Internal Medicine.

The investigators recruited 240 men and women (average age 55) with mild to moderately high LDL-cholesterol levels from several cities in China. All of the participants were generally healthy and not taking any medications or dietary supplements that would influence cholesterol levels. The volunteers were instructed to maintain their usual low-fat diet, tea intake, and activity levels.

The volunteers were randomly assigned to consume either a green tea extract capsule or a sugar pill each morning for 12 weeks. Cholesterol levels were analyzed from blood samples drawn before, during, and at the end of the study.

At the study's start there was no difference in the lipid profiles of the two groups, but after 12 weeks total cholesterol fell more than 10% and LDL-cholesterol (the bad cholesterol) decreased more than 15% in the group taking the supplement. There were no significant changes in the lipid profiles of those taking the sugar pills.

How it might work

The researchers did not examine just how a green tea extract may influence cholesterol levels, but previous studies show that compounds in green tea may lower the amount of cholesterol that gets absorbed into the body, increase the amount of cholesterol and fat that gets excreted as waste, and thus reduce cholesterol concentrations in the liver.

Mixed findings

Other studies have contradicted these findings, showing no effect of drinking tea or consuming tea extract supplements on cholesterol profiles. It's important to note that in this study, the volunteers were eating a diet that is lower in saturated fat and cholesterol than the typical American diet and many were drinking, on average, one to four cups of tea a day in addition to the capsules. The researchers are not certain that the cholesterol-lowering effects of the supplements were not influenced by these additional factors.

Don't change tea-drinking habits yet

As with many questions, this one needs far more research before there is a clear answer about the effects of green tea. In fact, despite these findings, the investigators do not suggest taking tea supplements in the hope of improving heart health. If you drink green tea, enjoy it. But if not, the advice of The Cholesterol Education Program is far more potent for heart disease prevention: follow a diet that is low in saturated fat and cholesterol, be physically active, and lose weight if necessary.