Research continues. Studies still support potential benefits for improving cardiovascular health, battling cancer and weight reduction.
So don’t count out tea, including green tea extract, as a healthful addition to food and beverage formulations, even though the U.S. Food and Drug Administration last July shot down a petition for green tea. The petition requested a qualified health claim based on the consumption of green tea and a reduced risk of certain forms of cancer.
The F.D.A. stated "Two studies do not show that drinking green tea reduces the risk of breast cancer in women, but one weaker, more limited study suggests that drinking green tea may reduce this risk. Based on these studies, F.D.A. concludes that it is highly unlikely that green tea reduces the risk of breast cancer."
"It hurts in my view to see a claim go in and get rejected," said Dr. Jeffrey Blumberg, professor of nutrition at Tufts University in Boston. "That’s not good publicity."
He said a claim linked to hearth health may have fared better.
"There is much better evidence for tea and cardiovascular benefits than for tea and cancer," he said. "There really are only small trials with (cancer) prevention. There are actual studies with clinical cardiovascular outcomes."
Multiple petitions for specific health claims for green tea have been submitted to the F.D.A., said Steve Wang, sales manager for Taiyo International, Inc., Minneapolis. He said an Internet search of "green tea health benefits" may return more than 2.5 million hits.
"The recently denied petition had very little chance of approval as it petitioned for claims that green tea may reduce the risk of certain forms of cancer," Mr. Wang said. "While there is an abundance of clinical information on green tea and its health benefit as observed in vitro and in animals, additional studies with humans is needed to provide more conclusive evidence."
The F.D.A. has said it will consider new research findings.
"F.D.A. intends to evaluate new information that becomes available to determine whether it necessitates a change in this decision," the F.D.A. said when the petition for a tea health claim was denied.
Dr. Blumberg currently is working to determine the bioavailability of tea catechins in older adults and their antioxidant capacity alone and in combination with other dietary antioxidants. His work is part of a U.S. Department of Agriculture research project entitled "Dietary Antioxidants, Aging and Oxidative Stress Status."
An abundance of polyphenols, particularly flavonoids, gives tea its potential for health benefits. The major flavonoids in green tea are catechins. Studies on tea have explored benefits in such areas as oral care, heart health, weight loss and lowering cholesterol.
"I would tell you, as anybody from the scientific community would tell you, these are all suggestions from researchers," said Dr. Blumberg, a member of the scientific advisory panel for the Tea Council of the USA. "There is no definitive evidence." All comes from the same plant, Cam e l l i a sinensis. Processing methods determine what type of tea is produced. Green tea is unfermented; oolong is partially or semi-fermented and black tea is fermented totally, Mr. Wang said. According to 2003 statistics from the U.S.D.A., about 75% of the tea produced in the world is black tea. Green tea makes up 23% and oolong makes up the other 2%.
Green tea is dried quickly by steaming or pan-firing. The action inactivates enzymes, which allows green tea to maintain its natural, chlorophyll color and high catechin content, according to Taiyo.
Several catechins are present in significant quantities in green tea, said Juan Menjivar, director of lipids, Kerry Ingredients – Kerry Specialty Ingredients, Beloit, Wis. Epigallocatchin gallate (EGCG), the most powerful of the catechins, account for up to 50% of the total catechin content.
Kerry now offers creamers that are enhanced with green tea extract and may work in applications for beverages, meal kits, sauces, side dishes and soups. Beverages such as soy chai, fruit smoothies and fruit beverage blends may contain green tea or green tea extract, Mr. Menjivar said. Green tea and green tea extract also have appeared in breakfast cereals, cereal bars, dairy products and prepared foods.
"Any food or beverage product could be considered," Mr. Menjivar said. "From a consumer’s standpoint, it is more likely that we will see green tea fortification in food products where consumers expect to get their daily allowances of healthy ingredients."
Taiyo offers green tea powders, or Matcha Powders, and green tea extracts. Powders are made from tea leaves that have been ground or milled. The powders are not water soluble and will precipitate in solution without the aid of stabilizers/emulsifiers. Green tea extracts are made from the tea infusion, which produces a fine powder that is water-soluble.
Taiyo’s processing methods do not affect the tea’s antioxidant capabilities negatively, Mr. Wang said. Taiyo extracts the polyphenols and catechins to remove and reduce unwanted elements found in tea such as caffeine and bitterness compounds.
Since the F.D.A. has no health claim for green tea, it is difficult to know what dose of green tea per serving is needed to achieve health benefits, Dr. Blumberg said. In contrast, a recent health claim for plant sterols allows food manufacturers to know how much of that element to include per serving.
In the case of green tea, typically recommended doses are 125 mg to 500 mg extract per day, standardized to at least 60% polyphenols or EGCG, which is about four to 10 cups of brewed green tea, Mr. Menjivar said.
Besides dosage level, food and beverage formulators using green tea extract must consider flavor goals. Depending on the amount used, green tea may impart a bitter taste and possibly some undesirable color, such as orange, Mr. Menjivar said.
Mr. Wang said Taiyo offers a full line of both bitter and non-bitter green tea extracts. The lowest concentration runs at about a 30% polyphenol concentration, which allows for a significant level of antioxidants while retaining a fresh green tea taste.
Although Western consumers tend to prefer black tea over green tea, Americans see green tea as exotic and many Americans have heard of its health benefits, Dr. Blumberg said.
Mr. Wang expects green tea acceptance to increase among Americans.
"With the recent awareness, acceptance, attention and fascination with Asian culture in America, combined with consumers’ desire to consume functional daily foods, Asian foods and customs are making their way into the American ‘chic’ mainstream, where the hunger and appetite for all-things-Asian is rapidly growing," he said.