I admit that
I have a “drinking” problem—I am addicted to green tea! For me, it’s a taste that I’ve grown used to since
when I was little. My dad was a big tea
drinker. As far as I could remember, the
only “water” form I drank is tea, starting from daddy’s cup, of course.
Green tea is
known to be packed with antioxidants, to which most of the green tea health
benefits have been attributed, including green tea’s anti-aging effect. Recently, I had an honor of meeting a world leading
gut microbiota expert. Over the dinner,
we chatted about carbohydrates (i.e., starch)’s effect on gut microbiota. The professor told me that carbohydrates promote
good gut microbiota population according to his research. However, the problem is that carbohydrates in
our food are so easily digested by starch hydrolyses (i.e., enzymes) in mouth
and stomach, very small amount of carbohydrates can survive the upper digestive
track and reach our guts. As a side
effect, because the starch is so easily digested, the blood glucose tends to shoot
up quickly during the meal, leading to glycemic shock for diabetics.
The
discussion made me think that, if tea could inhibit the activity of starch hydrolyses,
starch would be digested more slowly and more will reach gut promoting the
healthy microbiota population. With
that, I started digging. It turns out
that green tea’s inhibition effect on starch digestion is a well-researched
area.
As early as
in 1998, Forsyth Dental Center researchers compared the inhibition effect of
salivary amylase by black and green teas and their effects on the intraoral
hydrolysis of starch. It was found that both black
and green teas inhibited amylase in human saliva. Since salivary amylase hydrolyzes food starch
to low molecular weight fermentable carbohydrates, experiments were carried out
to determine whether tea decoctions would interfere with the release of maltose
in food particles that became entrapped on the dentition. The results showed
that tea consumption can be effective in reducing the cariogenic potential of
starch-containing foods such as crackers and cakes. Tea may reduce the tendency
for these foods to serve as slow-release sources of fermentable carbohydrate.
In 2012, Penn
State University researchers published a paper on “Molecular Nutrition &
Food Research.” The paper examined
the effect of co-administration of green tea polyphenol, (-)-epigallocatechin-3-gallate,
on blood glucose levels following oral administration of common corn to fasted
CF-1 mice. It was found that green tea
polyphenol significantly reduced postprandial blood glucose levels after
administration of corn starch. But the
same effect was not observed on postprandial blood glucose following
administration of maltose or glucose, suggesting that green tea polyphenol may
modulate amylase-mediated starch digestion.
An article published in 2012 on J.
Agric Food Chem by a group of researchers from Oregon State University evaluated
the inhibitory effects of plant-based extracts including green tea, and white
tea and their constituent flavan-3-ol monomers (catechins) on α-amylase and
α-glucosidase activity, two key glucosidases required for starch digestion in
humans. Results showed that tea extracts and catechin 3-gallates were potent
inhibitors of α-glucosidase.
A group from
Oxford Brookes University published a paper in 2013 on the International Journal of Food Science. In the paper, the authors noted that green tea was the only tea shown to significantly reduce
sugar release from white bread.
Therefore,
green tea not only retards the wrinkle formation through its antioxidants’
radical scavenging effect but also reduces the starch digestion and prevents spiking
of blood glucose level. If you would
recall from my previous post, high concentration of blood glucose level promotes
the glycosylation of collagen, which causes skin aging, sagging and
wrinkle.
In
addition, green tea allows more starch and carbohydrate nutrients to reach gut therefore
promoting health gut microbiota population, which is known to have the effect
of reducing systemic inflammation and stress.
If
you are still not convinced of the benefits of drinking green tea, green tea is
also shown to reduce risk of coronary heart disease [K. J. Mukamal, K.
MacDermott, J. A. Vinson, N. Oyama, W. J. Manning, and M. A. Mittleman, “A
6-month randomized pilot study of black tea and cardiovascular risk factors,” The American Heart Journal, 154(4), pp.
724.e1–726.e1, 2007], stroke incidence [S. O. Keli, M. G. L. Hertog, E. J. M.
Feskens, and D. Kromhout, “Flavonoids, antioxidant vitamins and risk of stroke:
the Zutphen Study,” Archives of Internal
Medicine, 154, pp. 637–642, 1995], chronic inflammation [V. Sharma and L.
J. M. Rao, “A thought on the biological activities of black tea,” Critical Reviews in Food Science and
Nutrition, 49( 5), pp. 379–404, 2009], and cancer incidence [T. Kuzuhara,
M. Suganuma, and H. Fujiki, “Green tea catechin as a chemical chaperone in
cancer prevention,” Cancer Letters, 261
(1), pp. 12–20, 2008]. So, before your
next meal, order a green tea and start drinking your way to a perfect skin and
a greater health.
Thanks
for reading.
Connie
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