Excerpted from Yahoo! News, Thursday, 30 January 2003.

Steep Claims For Tea Extracts

Nanci Hellmich, USA Today -- For several years, tea has been touted for its possible health benefits, especially for preventing heart disease.

Now a growing number of dietary supplement makers, including a leading vitamin manufacturer, are adding green or black tea extracts to products with the promise that they'll increase metabolism -- in other words, burn more calories. Among the new products:

• Bayer's One-A-Day WeightSmart, a multivitamin with green tea extract, among other things. The package says it will "enhance your metabolism."
• Xenadrine EFX from Cytodyne Technologies, made with green tea extract, bitter orange and other ingredients. The label calls it a "rapid fat loss catalyst."
• GNC's Total Lean, a dietary supplement that contains guarana seed extract (caffeine), black tea leaves extract and other extracts. The label says it "boosts energy and metabolism."

Some of the products were designed as alternatives to weight-loss supplements with ephedra, a controversial ingredient that has been linked to numerous health problems and deaths.

But several national tea researchers and dietary supplement experts say the metabolism claims for tea are based on a few small studies, and they argue that the verdict is still out. "The studies are suggestive but not conclusive on tea's effect on metabolism," says Mark Blumenthal, founder of the American Botanical Council.

The research includes:

• A study of 12 normal-weight men by Department of Agriculture researchers. It showed that when the men drank five cups of water with caffeine in eight hours, they had a 3.4% increase in calories burned in a 24-hour period compared with drinking plain water. When they drank five cups of oolong (dark) tea containing the same amount of caffeine, they had a 2.9% increase in calories burned. The difference between the tea and the caffeinated water was not statistically significant. After drinking the tea, they also experienced an increase in the amount of body fat that was used as fuel, suggesting that the caffeine and other components of tea can mobilize fat stores for use as energy, experts say.
• A study of 10 healthy young men conducted by Swiss researchers showed a roughly 3% to 4% increase in calories burned for men taking green tea extract and caffeine over those taking caffeine alone or a placebo. They also found an increase in the use of fat as fuel for those consuming the green tea extract.

"Anything we find with tea will probably be a small effect," says Beverly Clevidence, a research nutritionist at the USDA's Diet and Human Performance Laboratory in Beltsville, Md., who worked on the USDA study.

"In our study, men burned, on average, an additional 65 calories during the day that they drank the five cups of oolong tea. Scientists aren't sure whether it's the caffeine or the components called catechins in tea that may cause the metabolic increase," she says.

Tea researcher C. S. Yang, chairman of the department of chemical biology at Rutgers University, says, "There is no clear evidence that the EGCG (catechins) in green and black tea increase metabolism. The increase may be mainly due to the caffeine."

But Mary Hardy, medical director of the Cedars-Sinai Integrative Medicine Program in Los Angeles, believes that both the catechins and caffeine in tea "have a modest but real effect on metabolism."

Still, laboratory studies on metabolism are difficult to do, and often the margin of error in a study is larger than the percent differences among treatment groups, says Tim Church, medical director of the Cooper Institute in Dallas. "Anytime anyone says something increases metabolism, a big red flag goes up.

"As we know it right now, there are no substances that will preferentially get rid of fat."

However, the manufacturers say their products will make a difference.

Bob Chinery, president of Cytodyne Technologies in Manasquan, N.J., which makes Xenadrine EFX, says the combination of a specific green tea extract and bitter orange increases metabolism, "enabling the body to burn calories quickly." The company has financed research on its product.

Experts say that to answer some of the questions about tea, more research is needed. "There needs to be controlled weight-loss studies," Hardy says.

Meanwhile, these products are on the government's radar screen. "We are aware that green tea extract has become more popular in weight-loss supplements and that the promotional literature touts it as a metabolism booster," says Richard Cleland, an attorney with the Federal Trade Commission. "At this point, the publicly available evidence is not adequate to demonstrate that green tea extract will have a profound effect on metabolism or cause substantial weight loss."

The FTC won't say whether it's investigating the claims or advertising for the products.

Excerpted from Yahoo! News, Thursday, 30 January 2003.