They say switching to green tea is good for your health. But how? And is it worth the trouble? We asked London tea experts, Newby Teas, to give us the lowdown on the possible benefits of giving green tea the green light.
The first point to clear up is that green tea is made from the same leaves as black tea, but the leaves are steamed and less fermented than they are in the production of black tea.
Many of green tea’s health properties are attributed to its high level of flavonoids called catechins, which act as antioxidants.
These reduce the formation of free radicals which are known to play a part in the occurrence of many diseases and the ageing process.
It is known that the chemical structure of flavonoids differs in black and green tea due to the differing production processes, with green tea containing more of the simple flavonoids. However, the overall antioxidant properties are similar in both types of teas.
Many studies have been carried out which highlight the benefits of green tea with regard to a variety of health conditions. However, the reliability of some studies has been questioned by health professionals, who cite a lack of reliable evidence or point to contradictory findings.
This makes it difficult to categorically assert any particular health benefit – a situation not helped by the vast difference in quality available on the green tea market (a kilo can sell for anything from $50 to $10 million).
The results may, however, help tea drinkers to make a more informed decision on their choice of tea. With this in mind, here are the details of some of the research which has taken place around green tea and health:
1) Weight loss
Green tea is a commonly used ingredient in dietary supplements, as trials have shown it can help burn fat and boost the metabolic rate. Some studies have indicated it has an effect on weight loss, especially in the abdominal area, and some suggest the effect is even greater when exercising.
However, this may depend on the individual, and some studies demonstrate no significant effect on weight at all.
Some studies have indicated that green tea can reduce blood sugar levels and improve insulin activity, and reduce the risk of developing type-2 diabetes.
Some have even claimed that drinking 3 cups of tea a day (black or green) could reduce this risk by 40% – while others find no link at all. It has also been suggested elsewhere that adding milk to your tea reduces the sensitivity to insulin, and thus the effect.
Other foods which are also high in polyphenols – such as fish, nuts and some fruits and vegetables – are also thought to be effective in the prevention of type-2 diabetes.
3) Dental health
Studies have shown that the catechins in green tea can inhibit the build-up of harmful bacteria in the mouth, namely streptococcus mutans. This bacteria can lead to plaque, which in turn leads to tooth decay and cavities.
Other studies have compared green tea’s ability to reduce bad breath with those of other foods such as chewing gum and mints, and found it to have a superior deodorising effect.
4) Cardiovascular health
A number of studies have provided positive indications that green tea consumption can help to lower cholesterol, LDL cholesterol and triglycerides, all major contributing factors in the development of heart disease.
However, it isn’t yet clear how much tea you would need to consume for there to be a significant effect, and longer-term studies may be required to lend more credibility to these findings.
5) Mental health
The amino acid L-theanine, present in green tea, works alongside the caffeine in the drink to improve brain function, and studies have found this to be a particularly effective combination.
Others have tested the effect of the catechin compounds in green tea on neurons, albeit on animals, and suggested they could have the potential to lower the risk of Alzheimer’s and Parkinson’s Disease. However, this is - as yet - unproven when it comes to humans.
Green tea’s well-established antioxidant properties have been cited as having the potential to reduce the risk of cancer, because oxidative damage is known to be a contributor to the development of the disease.
Some people attribute the lower rates of some cancers in Asia to the popularity of green tea in the region, and some cancer sufferers believe it helps boost their immune system, rid their bodies of toxins and improve their general wellbeing.
While some lab studies have shown that green tea extracts can inhibit the growth of cancer cells, the consensus at this time is that there is not nearly enough credible evidence to establish the efficacy of green tea in preventing cancer, and previous reviews of a number of studies have found the link to be weak and unreliable.
As the wealth of research to date shows, there is clearly an incentive to investigate the healing properties of green tea, and some of the results to date could be seen as encouraging.
It is worth undertaking a little research of your own, however, if you see green tea being marketed as a panacea to cure all known ills – the health benefits are far from beyond reasonable doubt.
Our advice is to enjoy green tea for its taste – ideally without sugar – and treat any potential benefits as a bonus. Newby takes the trouble to preserve its teas at an optimal temperature, keeping its colour, moisture and character intact.
When prepared with care, the drink opens up a world of exciting flavours you’ll want to discover for their own sake.