(Jamaica Gleaner) Tuesday | April 12, 2016 | 12:00 AM
Tea is the most consumed beverage in the world, besides water, and has been used by man for millennia. Medical research highlights the many health benefits of a specific tea – green tea, a drink made from the leaves of the tea plant (Camellia sinensis). The same plant that produces green-tea also makes other teas like black tea and oolong tea. But green tea is truly unique because of a special process the Chinese had developed thousands of years ago.
Scientists today continue to find more health benefits from this beverage. These had been attributed to potent antioxidants found in the tea leaves called polyphenols. These substances are also found in much smaller amounts in other beverages like cocoa and coffee.
Recently, however, researchers have identified another substance that is found exclusively in the tea plant. It is a special amino acid called theanine that accounts for the ability of tea to create relaxation while energising the drinker. Theanine is the predominant amino acid in green tea leaves and gives tea its characteristic taste while contributing many other benefits.
Theanine combats stress
When someone suggests that you have a cup of tea and relax, they are really asking you to have a cup of theanine. Green tea contains small quantities of natural caffeine, and the calming effect of the theanine balances the stimulating effects of caffeine on the nervous system. This theanine-created sense of relaxation occurs about half an hour after ingestion by two separate actions.
First, it acts on the brain to produce both relaxation and mental alertness. Second, theanine increases the levels of the brain chemicals dopamine and serotonin that produce feelings of well-being and relaxation. Theanine helps relieve stress without producing sedation or drowsiness.
Theanine promotes learning
Theanine enhances your ability to learn, remember and concentrate, a reason why monks and scholars have historically used drinking green tea as an aid to meditation and study. It particularly helps with multi-tasking, allowing you to focus better.
Researchers found that it even synergises with caffeine to boost the activity of brain cells. They found that 100 milligrams of theanine and 60 milligrams of caffeine found in about four cups of green tea enabled subjects to perform better on complicated tasks.
Theanine and cancer
A study published by Sadzuka et al in 2002 found that theanine might help cancer patients by improving the efficacy of chemotherapy. Theanine increased the concentration of anti-cancer drugs in tumours while decreasing the levels of the drugs in the healthy tissues where they are not wanted. This made the therapy work better while decreasing side effects. In addition, theanine itself also inhibited the growth of cancer cells.
In Japan, where green tea is very popular, surveys showed that regular green tea drinkers had a much lower incidence of breast, prostate, liver, pancreatic, lung, oesophageal and stomach cancers.
Blood pressure and cholesterol
Japanese researchers report that theanine lowers high blood pressure but has no effect on normal blood pressure. Studies have shown that theanine is particularly useful in ‘spontaneous hypertension’, which is high blood pressure resulting from stress, excitement, or shock. The soothing, calming effects of theanine appear to offset this dangerous condition.
Theanine was also found to reduce total cholesterol levels in humans, while preventing good cholesterol from becoming dangerous by oxidation.
Theanine improves immune function
Studies demonstrated that theanine increased the body’s immunity against colds and flu and promotes a strong immune response to infections. It also aids in preventing allergies and autoimmune diseases.
Theanine for weight loss
Green tea is well known to help with weight loss, and theanine contributes to this fat-burning effect. Research using animals found theanine lowered body weight, body fat and triglycerides (blood fat) levels. Tea contains zero calories, and helps to curb food cravings. The social habit of ‘afternoon tea’ was supposedly started by the seventh Duchess of Bedford in England to quiet her hunger pangs between lunch and dinner.
Theanine is safe and non-toxic and drinking green tea is associated with very few side problems. Staining of the teeth is probably the commonest issue, and using a toothpaste containing bicarbonate and hydrogen peroxide can prevent this. By the way, green tea prevents bad breath (halitosis) as the polyphenols in tea inhibit bacteria in the mouth that can cause this unpleasant odour. For people who are caffeine-sensitive, you can overcome this by starting with small amounts of green tea while supplementing with magnesium and the B vitamins.
Benefit from green tea
In order to get all the benefits from green tea, one would need to drink several cups of green tea daily. Modern technology has creating a patented organic green tea concentrate in powder form. Half of a teaspoonful of the powder (herbal tea concentrate) makes a cup of tea (hot or cold) that provides the benefits of several cups of regular green tea leaves. I use this green tea concentrate myself and recommend it to all my patients. It is an ideal healthy breakfast beverage.