Green tea extract effective for weight loss at low doses

Daily supplements of a purified extract of green tea may increase energy expenditure and help men beat the bulge, say results from a new human study.

A low dose of epigallocatechin gallate (EGCG) from green tea was found to increase fat oxidation by 33 per cent, according to findings published in the European Journal of Clinical Nutrition.

“This pilot study provides for the first time evidence that a single green tea catechin, EGCG, can increase fat oxidation in obese men, at least within 2 h after meal intake. Within this postprandial phase, EGCG is equipotent with caffeine with regard to fat oxidation,” wrote the authors, led by Frank Thielecke from DSM Nutritional Products.

Growing waistlines, growing market

With the World Health Organization estimating that by 2015, there will be more than 1.5 billion overweight consumers, incurring health costs beyond $117 billion per year in the US alone, the opportunities for a scientifically-substantiated weight management food product are impressive.

Green tea has been studied extensively for its potential in the weight management category, with the compound epigallocatechin gallate (EGCG) highlighted as a key component.

Three mechanisms have been proposed: EGCG could increase energy metabolism and fatty acid oxidation; inhibit fat cell development (apidogenesis); and/or reduce lipid absorption and increase fat excretion.

It has also been reported that caffeine must also be present as, for EGCG to aid weight loss, a stimulated nervous system is needed.

The new research, performed in collaboration with scientists from Universitary Medicine Berlin, supports the link between caffeine and EGCG, but also found that the compounds produce similar effects. A daily dose of 300 mg of EGCG was associated with a 33 per cent increase in fat oxidation, while a daily dose of 200 mg caffeine was linked to a 34.5 per cent increase. When male subjects were given a combination of EGCG (300 mg) and caffeine (200 mg), fat oxidation increased by almost 50 per cent, added the researchers.

The EGCG used in the study was DSM's Teavigo ingredient, with 94 per cent EGCG purity.

Study details

Thielecke and his co-workers recruited ten healthy overweight and obese men (average BMI of 31.3 kg/m2) to participate in the randomized, placebo-controlled, double-blind crossover trial. The men were randomly assigned them to one of five groups: Placebo, low-dose EGCG (300 mg), high-dose EGCG (600 mg), caffeine (200 mg), or EGCG plus caffeine (300 mg/200 mg). The men took the supplements for three days, then seven days of washout, and cross-over to another group. At the end of the study, all the men had participated in each group.