HEALTH BENEFITS OF TEA WITH SPECIAL EMPHASIS ON GREEN TEA

By Dr D B Nugegoda

History of tea dates back to ancient China almost 5000 years ago! Hence this beverage is well and truly time tested. Research has unearthed an array of health benefits of this very healthy beverage which plays a vital role in both prevention and management of almost all the chronic diseases faced by man today. Both black tea and green tea benefit our health, however green tea has more anti-oxidants than black tea and hence superior, as some of the anti-oxidant power of green tea is destroyed when it is converted to black tea. It should also be noted that adding milk to tea wipes out its benefits.

CANCER

A study conducted by Professor Aedin Cassidy found women taking two cups of black tea daily to have a 31 % reduction in their risk of getting ovarian cancer.

In 1994, the Journal of the National Cancer Institute published the results of an epidemiological study, which indicated that drinking green tea reduces the risk of oesophageal cancer among Chinese men and women by nearly 60 %. Researchers from the University of Purdue concluded that a compound in green tea inhibits the growth of cancer cells. The secret of green tea is said to be due its high catachin polyphenols, especially epigallocatechin gallate (EGCG). EGCG is a powerful antioxidant, which inhibits growth as well as kills cancer cells. Recently it had been found that green tea also makes anti-cancer drugs more effective, by blocking the protective function of cancer cells (Reader’s Digest, Jan. 2010). Hence, it is advisable that all cancer patients on cancer medication additionally drink green tea. Even in relapse of breast cancer, drinking green tea has been found to make the drugs more effective; as it blocks the protective function of cancer cells. In a 1997 study, researchers from the University of Kansas found EGCG to be twice as powerful as resveratol, the powerful antioxidant found in red wine! Another study reported polyphenols in tea to inhibit the growth of a kind of bacteria that causes colon cancer.

ANTI-INFLAMMATORY ACTIONS

Chronic inflammation through the production of copious amounts of Pro-inflammatory Cytokines plays a vital role in the initiation and sustenance of diseases such as cancers, heart attacks, stroke, arthritis, diabetes, dementias, Alzheimer’s disease, etc. Tea, especially green tea has been found to possess very powerful anti-inflammatory properties, providing protection against all these diseases.

FAT BURNING PROPERTIES

Green tea helps burn excess fat in the body, including liver fat. Hence it helps people to overcome central obesity. Abdominal fat is like a factory producing copious amounts of pro-inflammatory cytokines, promoting all NCDs. In the present context with the pandemic of COVID 19, this fact is very important as people with central obesity are more prone to its complications, as the copious amounts of pro-inflammatory cytokines make the condition very serious. The American Journal of Clinical Nutrition has reported green tea helps in burning more calories, helping in weight reduction among the overweight and obese.

FATTY LIVER DISEASE (FLD)

In Sri Lanka the commonest liver disease is said to be FLD. FLD can happen due to alcohol, or even without alcohol. It is claimed that 80 % of cirrhosis in Sri Lanka is not due to alcohol, but due to deposition of excess amounts of fat in the liver, leading to FLD. It is estimated that about 50 % of young people in urban areas in Sri Lanka, suffer from FLD due to unhealthy life styles. FLD was a very rare condition a few decades ago! The danger of FLD is that if it is not reversed by adopting a healthy life style, after 10 to 15 years, it will end up in cirrhosis; the only treatment for which is a liver transplant! All young people should take special note of this serious situation.

In FLD there is constant destruction of liver cells releasing liver enzymes into the blood, detected by elevated liver enzyme levels. Green tea has been found to benefit people with FLD. According to an article in the International Journal of Preventive Medicine, green tea showed a significant reduction in liver enzymes, indicating an improvement in liver health. Hence alcoholics too will benefit immensely from green tea. Additionally due to its anti-fibrotic effect, green tea has a protective effect against cirrhosis, hepatitis C etc.

DIABETES

A Japanese study found a 33 % risk reduction of developing diabetes in subjects consuming 6 or more cups of green tea daily. Even among patients with diabetes, daily intake of green tea improved their sugar control.

Another study found green tea to provide protection against the Metabolic Syndrome, which consists of High blood Pressure, Insulin Resistance, Central Obesity, FLD. Metabolic Syndrome is a risk factor for fatty liver disease as well.

DEMENTIAS AND COGNITIVE FUNCTION

A very recent research conducted by the National University of Singapore found that regular tea consumption to reduce the risk of dementia by up to 86 % among the elderly, additionally there was an improvement in their cognitive fitness.

HEART ATTACKS / STROKES /HIGH BLOOD PRESSURE / KIDNEY DISEASE

Researchers at University College London found that people, who drank tea, de-stressed quickly and also showed lowering of the stress hormone, cortisol in their blood. They also found blood clotting to be lower among tea drinkers, due to lowered platelet activation making blood thinner, affording protection against heart attacks and strokes.

Green tea has also been found to lower total cholesterol levels, as well as to increase the ratio of good (HDL) to bad (LDL) cholesterol. It should also be noted that LDL by itself does not damage the inner lining of the arterial wall, as it has to be first oxidized. Here too the oxidation of LDL is impeded by the polyphenols present in tea!

A report in the European Journal of Clinical Nutrition stated that drinking 3 cups of tea reduces the risk of coronary heart disease. Another study found tea to lower cholesterol levels in people with elevated cholesterol levels.

A recent study published in the journal Cellular Physiology & Biochemistry, found anti-oxidants in tea to lower / control blood pressure, providing a protective effect against chronic kidney disease, heart attacks and possibly dementias.

PRECAUTIONS ONE SHOULD TAKE REGARDING TEA DRINKING

Certain chemicals in tea can interfere with the absorption of iron and other minerals from the diet. To overcome this problem, avoid consumption of tea just before and just after a main meal.

Drinking too much tea can increase your caffeine level in the blood, which can increase the anxiety level and also interfere with sleep if taken just before going to sleep.