Antioxidants from black tea may aid diabetics (Type IIs)

foodnavigator.com ^ | 29-Jul-2009 | Stephen Daniells

[neverdem]

Polysaccharides from black tea may blunt the spike in sugar levels after a meal more than similar compounds from green and oolong tea, and offer potential to manage diabetes, says a new study.

The black tea polysaccharides also exhibited the greatest activity for scavenging free radicals, which are linked to development of diseases such as cancer and rheumatoid arthritis, according to new findings published in the Journal of Food Science.

Interest in tea and its constituents has bloomed in recent years, with the greatest focus on the leaf’s polyphenol content. 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 new research looked at the polysaccharide content of green, black and oolong tea, and measured their ability to inhibit the effects of alpha-glucosidase activity. By inhibiting this carbohydrate hydrolyzing enzyme, it is possible to reduce the spike in glucose levels in the blood following a meal (postprandial hyperglycemia).

If additional studies support the potential effects of the polysaccharides, it could see the black tea extracts positioned in the diabetic supplements market. An estimated 19 million people are affected by diabetes in the EU 25, equal to four per cent of the total population. This figure is projected to increase to 26 million by 2030.

In the US, there are almost 24 million people with diabetes, equal to 8 per cent of the population. The total costs are thought to be as much as $174 billion, with $116 billion being direct costs from medication, according to 2005-2007 American Diabetes Association figures.

Study details

“Many efforts have been made to search for effective glucose inhibitors from natural materials,” said lead researcher Haixia Chen. “There is a potential for exploitation of black tea polysaccharide in managing diabetes.”

Researchers from Tianjin University isolated three polysaccharide-rich fractions from green, black, and oolong tea. The black tea was found to contain lower molecular weight polysaccharides. Green tea had a range from 9.2 to 251.5 KDa, while black tea polysaccharides ranged from 3.8 to 32.7 KDa.

When tested for their ability to inhibit alpha-glucosidase, as well as antioxidant activities relating to hydroxyl radicals and DPPH radicals, the black tea polysaccharides were found to produce the best results, said Chen and co-workers.

“The differences in antioxidant activities and glycosidase inhibitory properties among the three polysaccharide-rich fractions appeared to be related to differences in monosaccharide composition and molecular weight distribution of the polysaccharide,” wrote the researchers.

Source: Journal of Food Science Published online ahead of print, Early View, doi: 10.1111/j.1750-3841.2009.01231.x “Physicochemical Properties and Antioxidant Capacity of 3 Polysaccharides from Green Tea, Oolong Tea, and Black Tea” Authors: H. Chen, Z. Qu, L. Fu, P. Dong, X. Zhang

[neverdem]

The new research looked at the polysaccharide content of green, black and oolong tea, and measured their ability to inhibit the effects of alpha-glucosidase activity.

That's what Precose, aka acarbose, does.

[neverdem]

FReepmail me if you want on or off the diabetes ping list.

[Artemis Webb]

I used to manage a specialty coffee and tea store in Atlanta. Every time some BS article came out about tea (usually green tea) people who were ill (usually with cancer) would come in and buy up a ton of it. This was pathetic. Here's the deal:

Tea taste good hot.
The taste good iced.

TEA DOES NOT CURE OR HELP A DAMN THING! I guess if you are very sick and kind of desperate there are worse, not to mention more expensive things you can do with your money than throw it away on teas but you are throwing your money away regardless.

—Artemis Webb is now stepping off his soap box.

[rawcatslyentist]

Just great, now even peko will be expensive!

[magslinger]

self ping

[ottbmare]

Researchers at “Tianjin University” came up with these results. When they’re replicated by workers at Johns Hopkins, Stanford, Duke, Emory, Baylor, or Pritzker, you can take it to the bank. Until then, I’ll reserve judgment.

[I Buried My Guns]

is it because that's what happens to black tea in America?

That's racist.

[bert]

Black tea + cardamon + cloves + sugar = Chai

MMMM good!

[Conservativegreatgrandma]

I am brewing kombucha which is a fermented tea that has lots of probiotics, enzymes and vitamins and minerals. It is a lot of fun. It’s a nice fizzy drink.

[Artemis Webb]

Well by all means enjoy your drink. It’s probably a lot healthier than my concoctions I can assure you! :)