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

Mediterranean Diet and Brain Volume; Red Meat and Diverticulitis

People who follow a Mediterranean diet seem to retain more brain volume as they age, compared to people who don’t follow this diet.  A recent study from the University of Edinburgh in Scotland, published in the journal Neurology, followed 967 people without dementia, around age 70, testing them at 3 years and again at 6 years.  The subjects had an MRI brain scan at each follow-up.  The scans measured overall brain volume, grey matter volume and thickness of the brain’s cortex.  The measurements were compared to how closely the subjects followed a Mediterranean diet. People who didn’t follow the diet closely were found to have a higher loss of brain volume that people who followed it more closely.  The researchers adjusted for other factors that could affect brain volume, such as such as age, education, and having diabetes or high blood pressure.  The researchers concluded that the diet may be able to provide long-term protection for the brain, but more studies are needed to confirm the results.

The Mediterranean Diet includes large amounts of vegetables and fruits, olive oil, beans, cereal grain such as wheat and rice, moderate amounts of fish, dairy and wine, and limited amounts of meat.

Diverticulitis  A recent study from Harvard, published in the journal Gut, suggests that eating red meat is associated with an increased risk for developing diverticulitis.  Diverticula are small, bulging pouches that can form in the lining of your digestive system. They are found most often in the lower part of the large intestine – the colon.  Diverticula may never cause problems. However, one or more of these pouches may become inflamed or infected; this condition is known as diverticulitis. Diverticulitis can cause severe abdominal pain, fever, nausea and a marked change in your bowel habits.  Mild diverticulitis can be treated with rest, changes in your diet and antibiotics. Severe or recurring diverticulitis may require surgery.  The Harvard researchers analyzed health and diet information reported by more than 46,000 men over 26 years.  Men who ate the most red meat per week (about 13 servings) were 58% more likely to develop diverticulitis during the study period, compared to men who ate the least red meat. The association was strongest with steak.  The risk went down when people in the study substituted poultry or fish for red meat. Dr. Andrew Chan, the lead author of this study, wrote  “There is an idea that there is some pro-inflammatory state mediated by red meat that could contribute to inflammation in certain organs, Diverticulitis is a clear example of inflammation with serious consequences.”

Dear readers – there is an obvious take home lesson from these studies – eat thoughtfully!  Don’t forget that the helpful probiotic bacteria in your gut love fiber – found in vegetables, beans, fruits and whole, unprocessed grains.  

Sadja Greenwood, MD, MPH   back issues on this blog