In the resolute words of scientist, Dr Jinhua Li; “Tea has been a popular beverage since antiquity, with records referring to consumption dating back to the dynasty of Shen Nong, approximately 2700BC, in China.”
That being said, many of the studies relating to tea have been undertaken across the globe by all nationalities, representing the universal popularity of the drink.
While many nations, including Britain, favour black tea, the processing which takes place to prepare the leaves for market has a massive impact on its chemical composition. In fermenting black tea, the bioactive polyphenols are oxidised into pigments which may alter their anti-oxidant properties. In addition to this, many prefer to consume black tea with milk, which also reduces the efficacy of those bioactive components.
Green tea, on the other hand, has been a staple of billions of people across the world for millennia, but it’s only in recent years that scientists have started to investigate its true power.
1. Green tea can protect the heart.
Studies conducted at the Chinese Academy of Medical Sciences, found that the protective effects of tea were most pronounced among those subjects who were deemed habitual drinkers. Following mechanism research, senior author Dr Dongfeng Gu concluded that the main bioactive compounds in green tea, namely polyphenols, are not stored in the body long-term but require continuous replenishment. Those who partook for extended periods of time had a 25% lower risk for incidents of heart disease and strokes. By comparison, they found no statistical correlation for those who drank black tea.
In January of this year, The European Journal of Preventative Cardiology went as far as stating that drinking green tea at least three times a week is linked with a longer and healthier life, claiming that habitual tea drinkers had a 39% lower risk of heart disease, a 56% lower risk of fatal heart disease and stroke, and a 29% decreased risk of ‘all-cause’ death compared to never or non-habitual drinkers.
2. Green tea plus exercise is the ideal combination to reduce fatty deposits in the liver.
In February of this year, Associate Professor of Food Science, Joshua Lambert and colleagues at Penn State, published findings on the impact of polyphenols from green tea extract on the fatty tissues of mouse livers. Following sixteen weeks of high fat diets, the mice were placed into a range of groups to test the impact of polyphenols on lipid deposition.
Throughout the experiments, the rodents’ waste products were screened and at the end of the trial, their livers examined. Their discoveries gave them an insight into how these bioactive compounds may alter the biochemical pathways of digestion.
“We saw that the mice that consumed the green tea extract and had exercise actually were processing nutrients differently – their bodies were handling food differently.” Lambert said. “We think the polyphenols in green tea interact with digestive enzymes secreted in the small intestine and partially inhibit the breakdown of carbohydrate, fat and protein in food, so if a mouse doesn’t digest the fat in its diet, that fat and the calories associated with it, pass through the mouse’s digestive system and a certain amount of it ends up coming out in its faeces.”
Compared to the control groups, the mice who consumed green tea extract and had regular exercise were found to have just a quarter of the fatty deposits in their livers. Lambert thinks it might be something to do with how polyphenols impact gene expression related to the formation of new mitochondria, or the energy factories within animal cells.
While this is not exactly concrete proof of the correlation, it is certainly enough to warrant further studies.
3. Green tea may assist with allergies
Associate Professor of Chemistry at Kyushu University in Japan, Hirofumi Tachibana, identified the key polyphenol compound that in lab tests, blocked a specific receptor cell linked to an allergic response. This bioactive compound, Methylated Epigallocatechin Gallate, or EGCG, is a most abundant anti-oxidant found in green tea leaves. Although further tests are needed to provide conclusive proof, the initial findings indicate that EGCG blocks the production of histamine and immunoglobulin E, two naturally occurring chemicals in our bodies that help to sustain allergic reactions.
4. Green tea is linked to skin cell rejuvenation.
The same polyphenol, EGCG, has also been linked to promoting immune-responses by safeguarding healthy white blood cells and eradicating the free radicals that can alter DNA structure. If left to proliferate, free-radicals can damage DNA resulting in cancerous mutations.
Dr Stephen Hsu, Medical College of Georgia, studied human skin cell growth in relation to exposure to EGCG and found that it reactivated dying cells.
“Cells that migrate toward the surface of the skin normally live about twenty-eight days, and by day twenty, they basically sit on the upper layer of the skin getting ready to die, but EGCG reactivates them. I was so surprised.” Hsu said.
The team found that stem cells in deeper layers of the skin differentiate and grow more efficiently in the presence of this bioactive agent. Hsu noted that the potential benefits for skin conditions such as ulcers, psoriasis, rosacea, wrinkles and wounds is enormous.
Hsu went on to state; “If skin cells surrounding wounds or infections don’t heal in time, fibroblasts in the connective tissue may rush in to fill the void and cause scar tissue formation. If we can spur the skin cells to differentiate and proliferate, we can potentially accelerate the wound healing process and prevent scarring.”
This is exciting news for those suffering from conditions such as diabetes, where wounds can be particularly troublesome in healing.
5. Green tea can help to prevent arterial explosion.
Abdominal aortic aneurysms give the sufferer no warning signs. Essentially, the main artery in the gut can bloat and stretch without symptoms until one day it ruptures. If the patient is lucky enough to be close to a hospital, a surgeon can graft a new length of vessel onto the damaged region or insert stents to keep them alive. There is only a 50% survival rate.
In 2016, Kenji Minakata and Shuji Setozaki, at Kyoto University, Japan, discovered that the polyphenol in green tea, EGCG, reduces artery expansion in rats. They found that EGCG promotes the regeneration of elastin, an essential protein that gives artery walls strength and flexibility.
The rats were given an enzyme that induces gut aneurysms and found that the condition developed less in the group treated with green tea. They also saw less inflammation and more elastin production, protecting the arteries from rupture.
6. Green tea helps to silence dangerous genes
A study conducted by the American Chemical Society in 2018, reported that the green tea polyphenol, EGCG can form a nanoparticle with a natural modulator of genes in our bodies, enabling them to enter cells more readily.
These natural modulators, or Small Interfering RNAs can down regulate or switch off harmful gene sequences related to diseases. The problem is that siRNAs struggle to pass through the cell membranes. They are also easily degraded by certain enzymes which target them. Over the years, researchers have tested a variety of coatings, applied at the molecular level, but with limited success. In some instances, the experiments have proven toxic.
The bioactive chemical in green tea is known to bind strongly to RNA, so Wanwan Shen, Yiyun Cheng and colleagues, created nanoparticles using a small, positively charged polymer in conjunction with EGCG to safely deliver the siRNA across the cell membranes.
To test the efficacy, the team used a mouse model with intestinal injury and administered the nanoparticles using an siRNA that would specifically target an enzyme that promotes inflammation. Their results were sensational, in that the nanoparticles drastically improved symptoms, including weight loss, shortening of the colon, and reduced inflammation of the intestines.
The possibilities are exciting
It’s fair to say that the compound EGCG has enormous potential in the treatment of a range of ailments and diseases with no known adverse effects. While most of the studies investigating the compound have shown promising results, it will be some time before further trials can conclude that EGCG is the universal elixir it appears to be. The good news is that since it is found within a non-toxic beverage, there is no harm in trying out the benefits for ourselves.
There may even be many more aspects of our health that can benefit from green tea, including its impact on brain health.
Dr Jinhua Li and his team concluded, "In summary, our study comprehensively investigated the effects of tea drinking on brain connectivity at both global and regional scales using multi-modal imaging data and provided the first compelling evidence that tea drinking positively contributes to brain structure making network organization more efficient."
So, there you have it folks, drinking tea will make you think smarter, feel better and live longer.
Stay healthy one and all.