A theaflavin-enriched green tea extract significantly reduced LDL cholesterol in patients with raised cholesterol levels, report researchers this week.
They say that the supplement could be used, along with a low-saturated-fat diet, to treat hypercholesterolaemia.
Tea consumption has been associated with decreased cardiovascular risk, but potential mechanisms of benefit are ill-defined, noted the researchers from the Vanderbilt University Medical Center in Nashville, Tennessee in the US. While studies suggest that drinking multiple cups of tea each day lowers low-density lipoprotein (LDL) cholesterol, previous trials of tea drinking and green tea extract have failed to show any impact on lipids and lipoproteins in humans.
Working with researchers in Shanghai, the team carried out a double-blind, randomized, placebo-controlled, parallel-group trial in outpatient clinics in six urban hospitals in China. Around 240 adults, on a low-fat diet, with mild to moderate hypercholesterolaemia were randomly assigned to receive a daily capsule containing theaflavin-enriched green tea extract (375 mg) or placebo for 12 weeks. The theaflavin extract was provided by US-based Nashai Biotech.
After 12 weeks, total cholesterol and LDL-cholesterol were reduced by 11 per cent and 16 per cent respectively in the tea extract group. HDL-cholesterol and triglyceride levels were up 2.3 per cent and 2.6 per cent respectively. In the placebo group, the mean levels of total cholesterol, LDL and HDL cholesterol, and triglycerides did not change significantly. No significant adverse events were observed, wrote the researchers in the 23 June issue of the Archives of Internal Medicine.
The extract used in the study is currently being marketed in the US as a 375mg daily capsule under the name Teaflavin. Michael Vaughn, president and CEO of Nashai Biotech which makes the product, said: "For centuries in China, tea has been thought to possess properties to help maintain a healthy heart, and this study represents the first step in establishing the practicality, safety and LDL-cholesterol lowering efficacy of a tea product. Since there are few people who can or will drink that amount of tea, Teaflavin is a safe, non-pharmacologic and cost-effective option - a first-line therapy for maintaining healthy cholesterol levels."
These results were also featured as a poster presentation at the March 2003 meeting of the American College of Cardiology.