Switch to green tea, enjoy multiple benefits

While most Indians are fond of their cuppa red 'chai', fresh research shows that the green variety – already long considered have beneficial health effects – can be effective for battling dental complaints, fighting insulin resistance, as well as for improving cognitive abilities.

If your teeth are highly sensitive to that hot or cold drink, researchers in China have developed a new formula made with an extract from green tea that can fix this problem as well as help prevent cavities.

The findings indicated that green tea extract epigallocatechin-3-gallate (EGCG) stood up to tooth erosion and abrasive brushing and prevented biofilm formation.

When the protective layers of teeth are worn away, a bony tissue called dentin is exposed. This tissue contains microscopic hollow tubes that, when exposed, allow hot and cold liquids and food to contact the underlying nerve endings in the teeth, causing pain. Unprotected dentin is also vulnerable to cavity formation.

Cui Huang from Wuhan University in China and colleagues wanted to tackle sensitivity and beat the bacteria at the same time.  They used nanohydroxyapatite and EGCG, which has been shown to fight streptococcus mutans, which forms biofilms that cause cavities.

These ingredients were combined with the mineral silica nanoparticles, which can stand up to acid and wear and tear. They tested this on extracted wisdom teeth and found that the formula plugged the dentin tubules.

Dr Tim Bond from health group The Tea Advisory Panel also said that green tea compounds also act as a natural breath freshener.

The catechins (such as EGCG) stop adhesion of sugar containing materials - the basis of plaque upon which bacteria feed - producing acids which accelerate erosion of the tooth surface, the researchers noted.

The study was published in the journal ACS Applied Materials & Interfaces.

Cognitive boost
Meanwhile, another animal study suggests that the active ingredients in green tea can boost cognitive power.

The study, conducted by researchers at Northwest A&F University in Yangling, China, closely examines the average Western diet and offers yet another health-promoting reason to add some steeped tea leaves to your daily regimen. The findings seem very relevant to India, where diabetes is rampant.

Specifically, the researchers assessed how the most active components of green tea - known as catechins - might influence health outcomes on mice that showed signs of insulin resistance due to a high-fructose diet. Knowing that insulin resistance also leads to other harmful outcomes, the researchers speculated that improving insulin activity might have a positive downstream effect.

''Obesity increases the risk of insulin resistance and age-related cognitive decline, accompanied by peripheral inflammation,'' report the study authors in The FASEB Journal.

For the study, the researchers, like their Wuhan University counterparts, assessed EGCG, the most plentiful catechin contained in the tea leaves. They divided three-month old mice into three separate groups - one was fed a diet rich in high-fructose; another was given a high-fructose diet along with two grams of EGCG; and a third maintained a regular diet.

After about four months, the researchers discovered, perhaps unsurprisingly, that the mice fed a high-fructose diet had more body mass than the mice on a control diet. But they also found that mice on only a high-fructose diet had ''a significantly higher final body weight'' than the mice whose high-fructose diet was supplemented with the green tea catechins.

The results extended to cognitive power, too. The researchers had the three groups of mice undergo a Morris water maze test to assess their mental acuity. On every measure of the test, the high-fructose-only group performed worse than the mice that also consumed the EGCG supplements.

The study adds compelling evidence to support the overall benefits of green tea consumption, while finding even more reason to brew a batch.

EGCG, ''the major polyphenol in green tea, possesses antioxidant, anti-inflammatory, and cardioprotective activities; however, few reports have focused on its potential effect on cognitive disorders,'' report the study authors.

''To our knowledge, this study is the first to provide compelling evidence that the nutritional compound EGCG has the potential to ameliorate [high-fructose]-triggered learning and memory loss,'' the researchers add.

''Green tea is the second most consumed beverage in the world after water, and is grown in at least 30 countries,'' said Xuebo Liu, PhD, a researcher at the College of Food Science and Engineering at Northwest A&F University.

''The ancient habit of drinking green tea may be a more acceptable alternative to medicine when it comes to combatting obesity, insulin resistance, and memory impairment,'' added Liu.

Previously, studies have linked drinking green tea to lowering the risk of heart disease, protecting against cancer, promoting weight loss and improving one's mood and concentration.