Chamomile Tea May Prevent Diabetes Complications by Stephen Daniells
16-Sep-2008 - Drinking chamomile tea may prevent blood sugar
increases and other complications associated with diabetes,
suggests a new study from Japan and the UK.
Feeding diabetic rats the tea was also associated with lower
production of the sugar alcohol sorbitol from glucose, report the
researchers in the Journal of Agricultural and Food Chemistry. A
build-up of sorbitol is linked to damage in the eyes or of nerve
cells.
"The results [of this new study] clearly suggested that daily
consumption of chamomile tea with meals could contribute to the
prevention of the progress of hyperglycemia and diabetic
complications," wrote the researchers from the University of Toyama
in Japan and the Institute of Grassland and Environmental Research
in Aberystwyth, UK.
If the results can be repeated in other animal studies, and in
future human studies, it may see chamomile (Matricaria chamomilla
L.) tea added to the ever-growing list of dietary approaches for
the prevention and/or management of diabetes.
Indeed, Dr Victoria King, research manager at British charity
Diabetes UK, cautioned: "This study was carried out on rats with
diabetes during a 21-day period. More research would be needed
before we can come to any firm conclusions about the role chamomile
tea plays in fighting diabetes-related complications.
"Diabetes UK wouldn't recommend people with diabetes increase
their chamomile tea intake just yet."
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 seven per cent of the population. The total costs are
thought to be as much as $174 billion, with $116 billion being
direct costs from medical expenditures, according to 2007 American
Diabetes Association figures.
Study details
The researchers, led by Atsushi Kato, investigated the effect of
supplemental chamomile tea and its major components (umbelliferone,
herniarin, esculetin, isoscopoletin, apigenin, luteolin, quercetin,
R-bisabolol, and R-farnesene) to prevent or improve diabetic
complications.
Studies using rat cells and human red blood cells were
performed, while an additional feeding study was performed with
rats. Kato and co-workers report that the full hot water extract,
as well as esculetin and quercetin possessed moderate inhibitory
activity of sucrase enzymes, which are responsible for the
conversion of sucrose to fructose and glucose. Inhibition would
reduce the rise in glucose levels.
Moreover, inhibition of the enzyme aldose reductase (ALR2),
which converts glucose to sorbitol, was also observed when red
blood cells were incubated with the hot water extract and some of
the components.
"It has already been reported that the activity of erythrocytes
ALR2 increases in diabetic patients and erythrocytes sorbitol
levels in rats are positively correlated with the levels in the
lens, sciatic nerve, and retina," wrote Kato. Such a build-up can
produce damage and complications.
The researchers reported a 75, 79, 74, and 68 per cent
inhibition of ALR2 for umbelliferone, esculetin, luteolin, and
quercetin when the compounds were used at a concentration of 200
micromoles.
A 21-day feeding study used rats that had received an
intravenous injection of streptozotocin to induce diabetes.
Supplementing the diets of the animals with chamomile tea or its
extracts was found to influence blood glucose levels. Specifically,
the tea and quercetin were found to suppress blood glucose levels
in the animals.
"In conclusion, the present study demonstrated that daily
consumption of chamomile tea with meals could be potentially useful
in the prevention and self-medication of hyperglycemia and diabetic
complications," wrote the researchers.
Caution
Commenting independently on the results, Dr King said that more
research was needed to substantiate a potential role for chamomile
tea in diabetes prevention and management.
"Eating a healthy balanced diet, taking regular physical
activity and adhering to any prescribed medicines remain key ways
to effectively control blood glucose levels, blood pressure and
blood fats. Good diabetes management will help reduce the risk of
serious complications such as heart disease, stroke and blindness,"
she added.
Source: Journal of Agricultural and Food Chemistry Volume 56,
Pages 8206-8211 "Protective Effects of Dietary Chamomile Tea on
Diabetic Complications" Authors: A. Kato, Y. Minoshima, J.
Yamamoto, I. Adachi, A.A. Watson, R.J. Nash
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