Wing Lun Lim
Green tea comes from the leaves of the Camellia sinensis plant, more commonly known as the tea plant. It has been used for centuries to brew one of the world’s most popular beverages, now enjoyed by over 3 billion people worldwide and second only to water in global consumption. Green tea is often touted for its potential health benefits, including weight management, improved cognitive function, lower cholesterol, and a reduced risk of stroke. It’s also thought to help prevent certain diseases, but how much of this is actually backed up by scientific evidence? In this blog, we’ll explore what science actually tells us about this ancient brew, and bust a few myths along the way.
What Makes Green Tea Special?
What makes it different from black tea is that it’s processed in a way that preserves more of its natural compounds. Green tea leaves are quickly steamed or pan-fired after harvesting, which stops oxidation. This minimal processing helps preserve more of the plant’s natural compounds, especially antioxidants and other bioactive ingredients that contribute to its health benefits.
These include:
- Catechins – These natural antioxidants help neutralise free radicals, which can damage cells and contribute to ageing and disease. Catechins may also support heart health and reduce inflammation.
- Epigallocatechin gallate (EGCG) – The most studied catechin in green tea, EGCG is known for its potential to reduce inflammation, support metabolism and protect against chronic diseases such as heart disease and certain cancers.
- L-theanine – An amino acid that can promote relaxation without causing drowsiness. It works with caffeine to improve focus, attention, and mental clarity.
- Caffeine – The caffeine in green tea is present in smaller amounts than in coffee and provides a gentle energy boost. It increases alertness and can improve mood and cognitive function.
The Science-Backed Benefits of Green Tea:
1. Packed with Antioxidants:
Green tea is rich in antioxidants, particularly catechins, which help neutralise harmful molecules called free radicals. These antioxidants, along with other bioactive compounds in green tea, may play a role in reducing cell damage and lowering the risk of chronic diseases such as cancer and heart disease. A 2020 review suggests that green tea catechins may have a beneficial effect on several types of cancer, including breast, colon, oesophageal, lung, prostate and liver cancer. However, more human research is needed to prove these benefits.
The benefits of green tea aren’t limited to internal health. A 2018 review of in vitro, in vivo and human studies highlighted the potential role of tea polyphenols in preventing UVB-induced skin cancer.
2. Supports Heart Health
Green tea has been linked to several heart-protective effects, thanks to its powerful mix of antioxidants and plant compounds. Studies suggest that it may help reduce levels of LDL cholesterol (the ‘bad’ cholesterol), lower blood pressure and improve blood vessel function. These factors play a role in reducing the risk of heart disease, heart attack and stroke.
A 2023 study found that people who drank two to four cups of green tea a day reduced their risk of stroke by up to 24%. Other research highlights the role of compounds such as EGCG, catechins and flavonoids such as quercetin in improving cardiovascular health by reducing inflammation and preventing plaque build-up in the arteries.
A 2022 study linked green tea consumption to a lower risk of several conditions, including heart failure, hypertension, and ischaemic stroke.
3. Can Boost Brain Power
Beyond protecting the body, green tea’s unique blend of compounds may also benefit the brain. It contains a modest amount of caffeine. It provides a milder energy boost than coffee, without the jitters. Green tea also contains L-theanine, an amino acid that has been shown to improve concentration and reduce stress. The combination of caffeine and L-theanine may improve memory, alertness and overall brain function.
In addition to these effects, other compounds such as L-theanine and EGCG have also been studied for their potential to protect the brain. A study of middle-aged and older adults found that frequent green tea drinkers had a 64% lower risk of memory loss or concentration problems, almost 20% lower than those who drank black tea. Another study of people with cognitive decline found that green tea reduced biomarkers associated with Alzheimer’s disease. These findings suggest that including green tea in your diet may offer some protection against memory loss and cognitive disorders.
4. May Help with Weight Management
Many people believe that green tea burns fat and speeds up the metabolism. While some research supports this, the effects are modest. Drinking green tea alone won’t make a dramatic difference to weight loss, but when combined with regular exercise and a balanced diet, it can provide a small boost.
A 2021 review suggests that green tea and its main catechin, EGCG, may help people with obesity to lose weight. In addition, a further review of on tea polyphenols found that the combination of catechins and caffeine worked together to produce weight loss effects, rather than caffeine alone being the main contributor.
A 2022 study conducted in South Korea discovered that drinking four or more cups of green tea a day was associated with a 44% lower risk of abdominal obesity, although this effect was more significant in women. It’s worth noting, however, that green tea doesn’t seem to affect the hormones that regulate appetite, such as the hunger and satiety hormones.
Myth: “Green tea is a miracle cure for all illnesses”.
Fact: Green tea has some health benefits, but it’s not a panacea. A healthy diet and lifestyle are much more important for overall wellbeing.
Myth: “Drinking green tea will make you lose weight quickly”.
Fact: Green tea may slightly increase your metabolism, but it won’t help you lose weight unless you combine it with exercise and a healthy diet.
Myth: “The more green tea you drink, the better”.
Fact: While drinking 2-3 cups a day is generally beneficial, excessive consumption can cause problems such as insomnia (due to the caffeine) and digestive problems. Balance is key!
Conclusion
Green tea is a great addition to a healthy lifestyle, offering a mix of antioxidants, brain-boosting compounds and potential heart benefits. However, it’s important to be realistic: while it’s a healthy drink, it won’t work miracles. Enjoy your green tea, but remember that good health comes from a combination of smart choices, not just one magic drink!
Find out more:
Green Tea Catechins: Nature’s Way of Preventing and Treating Cancer
Green Tea (Camellia sinensis): A Review of Its Phytochemistry, Pharmacology, and Toxicology
Beneficial Properties of Green Tea Catechins
Beneficial Effects of Green Tea—A Review
How Green Tea Can Benefit Your Health
What are the health benefits of green tea?
10 Evidence-Based Benefits of Green Tea
10 Research-Based Benefits of Green Tea
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