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Citrus Juice, Vitamin C Give Staying Power To Green Tea

 
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JoeReal
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Joined: 16 Nov 2005
Posts: 4726
Location: Davis, California

Posted: Wed 14 Nov, 2007 7:03 am

This is good news. There are real benefits to squeezing sudachi, yuzu, calamondin or lemon juices into your Green Tea. And the source of this info is very credible, see link below

Joe


http://www.sciencedaily.com/releases/2007/11/071113163016.htm


Citrus Juice, Vitamin C Give Staying Power To Green Tea Antioxidants

ScienceDaily (Nov. 14, 2007) — To get more out of your next cup of tea, just add citrus juice.

A study found that citrus juices enable more of green tea's unique antioxidants to remain after simulated digestion, making the pairing even healthier than previously thought.

The study compared the effect of various beverage additives on catechins, naturally occurring antioxidants found in tea. Results suggest that complementing green tea with either citrus juices or vitamin C likely increases the amount of catechins available for the body to absorb.

"Although these results are preliminary, I think it's encouraging that a big part of the puzzle comes down to simple chemistry," said Mario Ferruzzi, assistant professor of food science at Purdue University and the study's lead author.

Catechins (pronounced KA'-teh-kins), display health-promoting qualities and may be responsible for some of green tea's reported health benefits, like reduced risk of cancer, heart attack and stroke. The problem, Ferruzzi said, is that catechins are relatively unstable in non-acidic environments, such as the intestines, and less than 20 percent of the total remains after digestion.

"Off the bat you are eliminating a large majority of the catechins from plain green tea," Ferruzzi said. "We have to address this fact if we want to improve bodily absorption."

Ferruzzi tested juices, creamers and other additives that are either commonly added to fresh-brewed tea or used to make ready-to-drink tea products by putting them through a model simulating gastric and small-intestinal digestion. Citrus juice increased recovered catechin levels by more than five times, the study found. Ascorbic acid, or vitamin C, used to increase shelf life in ready-to-drink products, increased recovered levels of the two most abundant catechins by sixfold and 13-fold, respectively.

The study, published this month in Molecular Nutrition and Food Research, also found that soy, dairy and rice milk appeared to have moderate stabilizing effects. But Ferruzzi said the result is misleading; a chemical interaction between milk proteins and tea catechins apparently helps shelter the complex from degradation, a force likely overcome by enzymes within a healthy human digestive system.

Lemons and tea go even better together than their popularity might suggest. Lemon juice caused 80 percent of tea's catechins to remain, the study found. Following lemon, in terms of stabilizing power, were orange, lime and grapefruit juices. Ferruzzi said both vitamin C and citrus juices must interact with catechins to prevent their degradation in the intestines, although data made it clear that citrus juices have stabilizing effects beyond what would be predicted solely based on their vitamin C content.

"If you want more out of your green tea, add some citrus juice to your cup after brewing or pick a ready-to-drink product formulated with ascorbic acid," Ferruzzi said.

Ready-to-drink green tea products should optimally contain 100-200 mg of catechins, but oftentimes do not have sufficient levels of tea extract since some people do not like green tea's flavor, Ferruzzi said.

Although this study only examined green tea, Ferruzzi said he suspects that some of the results also could apply to black tea, which is produced by fermenting green tea. Many prefer black tea's flavor, although it contains lower total levels of catechins.

Studies have shown catechins from the green tea plant, Camellia sinensis, are able to detoxify toxic chemicals, inhibit cancer cell activity and stimulate production of immune-strengthening enzymes. Finding methods to improve uptake of these catechins may, therefore, be important in improving health, part of the study's goal, Ferruzzi said.

Ferruzzi currently is conducting an in vivo study, or study on a live organism, to quantify the ability of juices and vitamin C to increase levels of catechins in the intestines and bloodstream of animals and, by extension, in humans. He collaborates with the NIH-funded Purdue Botanicals Research Center on this project.

"This next study is designed to get us past the limitations imposed by our digestive model, which is really just a simple screening process that relies on preset physiology parameters," he said. "Human digestion is a lot more complicated."

To see if juices and vitamin C actually increase catechin absorption, researchers will have to find out if increased levels of intestinal catechins translate to higher levels of absorbed catechins in live animals and humans. They also will need to better document effects upon catechin metabolism in order to prove, for instance, that increased levels of absorbed catechins are not leveled off by metabolic factors, Ferruzzi said.

"This study tells us a lot of interesting things, but it raises many questions that have yet to be answered," he said.

The study was funded by the National Institutes of Health.

Adapted from materials provided by Purdue University.
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JoeReal
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Joined: 16 Nov 2005
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Location: Davis, California

Posted: Thu 15 Nov, 2007 2:03 pm

Follow-up publications:

Citrus juice boosts green tea antioxidants
Published: Nov. 14, 2007 at 8:51 PM

WEST LAFAYETTE, Ind., Nov. 14 (UPI) -- Citrus juices enable more of green tea's unique antioxidants -- catechins -- to be available for the body to absorb, U.S. researchers found.

Lead author Mario Ferruzzi of Purdue University said catechins are relatively unstable in non-acidic environments, such as the intestines, and less than 20 percent of the total remains after digestion.

"Off the bat, you are eliminating a large majority of the catechins from plain green tea," Ferruzzi said in a statement. "We have to address this fact if we want to improve bodily absorption."

Ferruzzi tested juices, creamers and other additives commonly added to fresh-brewed tea or used in tea products by putting them through a model simulating gastric and small-intestinal digestion.

The study, published in Molecular Nutrition and Food Research, found citrus juice increased recovered catechin levels by more than five times, and ascorbic acid, or vitamin C, increased recovered levels of the two most abundant catechins.

Lemon juice caused 80 percent of tea's catechins to remain, followed by orange, lime and grapefruit juices.
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JoeReal
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Joined: 16 Nov 2005
Posts: 4726
Location: Davis, California

Posted: Thu 15 Nov, 2007 2:06 pm

Publication source:
Citrus boosts tea's antioxidant punch - study

By Stephen Daniells

14/11/2007 - Combining citrus juice or vitamin C with green tea or its extracts could increase the absorption of antioxidants from the tea up to 13-fold, suggests new research.

The research could have implications for functional food and beverage formulators looking to maximize the antioxidant profile and bioavailability of their products. It is not known if such benefits would be repeatable in supplement formulations.

The study is published in the Molecular Nutrition and Food Research.

"Although these results are preliminary, I think it's encouraging that a big part of the puzzle comes down to simple chemistry," said lead author Mario Ferruzzi, from Purdue University.

The researchers used a simulated gastric and small-intestinal digestion system to model the effects of juices, creamers and other additives on the

Tea and tea extracts have been linked to a number of health benefits, ranging from a lower risk of certain cancers to weight loss, and protection against Alzheimer's, have been linked to the polyphenol content of the tea.

Green tea contains between 30 and 40 per cent of water-extractable polyphenols, while black tea (green tea that has been oxidized by fermentation) contains between 3 and 10 per cent. Oolong tea is semi-fermented tea and is somewhere between green and black tea.

The four primary polyphenols found in fresh tealeaves are epigallocatechin gallate (EGCG), epigallocatechin, epicatechin gallate, and epicatechin.

However, according to Ferruzzi, the catechins are relatively unstable in non-acidic environments, such as the intestines, and less than 20 per cent of the total remains after digestion.

"Off the bat you are eliminating a large majority of the catechins from plain green tea," he said. "We have to address this fact if we want to improve bodily absorption."

The researchers formulated green tea water extracts in drinks to provide doses of epicatechin (EC), epigallocatechin (EGC), epigallocatechin-gallate (EGCG), and epicatechin-gallate (ECG) of 4.5, 18, 23, and 3.5 mg per 100 mL, respectively.

To these beverages, they added citric acid, BHT, EDTA, ascorbic acid (AA), milk (bovine, soy, and rice), or citrus juice (orange, grapefruit, lemon, and lime), and measured the stability of the catechins under the simulated gastric and small-intestinal conditions.

Adding the citrus juice led to increased stability of the catechins, and resulted in the highest recovery of EGC (81-98%), EGCG (56-76%), EC (86-95%), and ECG (30-55%) for any formulation.

Vitamin C at a dose of 30 mg in 250 mL of tea significantly increased catechin stability of EGC, EGCG, EC, and ECG to 74, 54, 82, and 45 per cent, respectively.

Addition of 50 per cent bovine, soy, and rice milk also produced increased total catechin stability under the simulated gastric and small-intestinal conditions of 52, 55, and 69 per cent, respectively, the authors reported.

"These data provide evidence that tea consumption practices and formulation factors likely impact catechin digestive recovery and may result in diverse physiological profiles," concluded the researchers in the journal.

Ferruzzi confirmed that the study was ongoing, with an in vivo study currently underway to quantify the ability of juices and vitamin C to increase levels of catechins in the intestines and bloodstream of animals and, by extension, in humans.

"This next study is designed to get us past the limitations imposed by our digestive model, which is really just a simple screening process that relies on preset physiology parameters," he said. "Human digestion is a lot more complicated."

The question also remains as to whether the juices and vitamin C actually lead to an increase in bioavailability of the catechins. Ferruzzi added that answers are needed to the question of whether the increased levels of absorbed catechins are not levelled off by metabolic factors.

The study was funded by the National Institutes of Health.

Source: Molecular Nutrition and Food Research
November 2007
"Common Tea Formulations Modulate In Vitro Digestive Recovery of Green Tea Catechins"
Authors: R.J. Green, A.S. Murphy, B. Schulz, B.A. Watkins and M.G. Ferruzzi
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bencelest
Citruholic
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Joined: 13 Nov 2005
Posts: 1596
Location: Salinas, California

Posted: Thu 15 Nov, 2007 2:10 pm

Ah!
Thanks Joe.
I'll save the above and send a copy to my sister who is watching her food intake and is a green tea lover.
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