Sunday, April 16, 2017

Tea Can Help Prevent Dementia and Tooth Decay

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   back issues on this blog

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