According to a study
from the Yong Loo Lin School of Medicine at the National University of
Singapore, tea drinking reduces the risk of cognitive impairment in older
persons by 50 per cent and as much as 86 per cent for those who are genetically
at risk of Alzheimer's.
The longitudinal study,
involving 957 Chinese seniors aged 55 years or older, found that regular
consumption of tea lowers the risk of cognitive decline in the elderly by 50
per cent, while APOE e4 gene carriers, who are genetically at risk of
developing Alzheimer's disease, may experience a reduction in cognitive
impairment risk by as much as 86 per cent. The research team also discovered
that the role of tea consumption on cognitive function is not limited to a
particular type of tea -- so long as the tea is brewed from tea leaves, such as
green, black or oolong tea.
"While the study was
conducted on Chinese elderly, the results could apply to other races as well.
Our findings have important implications for dementia prevention. Despite high
quality drug trials, effective pharmacological therapy for neurocognitive
disorders such as dementia remains elusive and current prevention strategies
are far from satisfactory. Tea is one of the most widely consumed beverages in
the world. The data from our study suggests that a simple and inexpensive
lifestyle measure such as daily tea drinking can reduce a person's risk of
developing neurocognitive disorders in late life," explained the
researchers. "Based on current knowledge, this long term benefit of tea
consumption is due to the bioactive compounds in tea leaves, such as catechins,
theaflavins, thearubigins and L-theanine. These compounds exhibit
anti-inflammatory and antioxidant potential and other bioactive properties that
may protect the brain from vascular damage and neurodegeneration. Our
understanding of the detailed biological mechanisms is still very limited so we
do need more research to find out definitive answers."
In this study, tea
consumption information was collected from the participants, who were
community-living elderly, from 2003 to 2005. At regular intervals of two years,
these seniors were assessed on their cognitive function using standardized
tools until 2010. Information on lifestyles, medical conditions, physical and
social activities were also collected. Those potential confounding factors were
carefully controlled in statistical models to ensure the robustness of the
findings. The research team published their findings in the journal The
Journal of Nutrition, Health & Aging in December 2016.
Future Research
The research team is
planning to embark on further studies to better understand the impact of Asian
diets on cognitive health in aging. They are also keen to investigate the
effects of the bioactive compounds in tea and test them more rigorously through
the assessment of their biological markers. They plan to conduct randomized,
controlled studies that assign
participants into experimental groups or control groups to eliminate biased
results.
Tea and Tooth Erosion
Today, the average
size soft drink is 20 ounces and contains 17 teaspoons of sugar. More startling
is that some citric acids found in fruit drinks are as erosive as hydrochloric
or sulfuric acid. These refined
sugars and acids found in soda and citrus juice promote tooth erosion, which
wears away the hard part of the teeth, or the enamel.
According to a 2008 article in the journal General Dentistry,
the peer-reviewed journal of the Academy of General Dentistry, the drink to avoid tooth erosion is water or
brewed tea,
Mohamed A. Bassiouny, DMD,
BDS, MSc, PhD, the lead author of the study, compared green and black tea to
soda and orange juice in terms of their short- and long-term erosive effect on
human teeth. He found that the erosive effect of tea was similar to that of
water, which has no erosive effect. And, when comparing green versus black, he
discovered that green tea was superior over black due to its natural flavonoids
(plant nutrients) and antioxidants.
If you do drink tea,
experts suggest avoiding additives such as milk, lemon, or sugar because they
combine with tea's natural flavonoids and decrease the benefits. In addition,
stay away from prepackaged iced teas because they contain citric acid and high
amounts of sugars. It does not matter whether the tea is warm or cold—as long
as it is home brewed without additives.
Sadja Greenwood, MD, MPH
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