Green Tea Health Benefits And Side Effects
Health benefits of green tea include weight loss, healthy skin and hair, and more. Read on to know about green tea benefits, green tea side effects and how to prepare the best green tea.
By Arun Sharma • 13 min read
Oscillating between sleep and wakefulness in the morning, as you bring the warm cup of freshly brewed tea to your lips, inhale the aroma and take a sip, you feel energised. A cup of your favourite tea doesn't just get you going, it makes your day. And, so it does to millions across the globe.
The health benefits of green tea for weight loss and healthy skin are widely known. But, are these the only reasons behind tea being crowned the 'most popular drink in the world'? Or, are there many more benefits of drinking green tea?
Let's wind our way through history and modern-day scientific research to find out how green tea attained its present-day exalted status.
History of tea
People across the world drink tea, but most of them don't know where tea originated from. The tea we buy from stores is produced from the leaves and leaf buds of a shrub called Camellia sinensis. There are two varieties of this plant (1) Camellia sinensis sinensis, which is native to China, and (2) Camellia sinensis assamica, which is grown in Assam, India.
An apocryphal story credits the Chinese Emperor Shennong, or Shen Nung, with discovering tea around 2737 BC. However, it was much later that the benefits of green tea were discovered and people started consuming it as a medicinal or health drink.
Sometime in the eighth century, Japanese Buddhist monks travelling to China brought tea seeds back with them. Thus, tea cultivation began in Japan. It was only in the early 1600s that tea was introduced to Europe by the Dutch and Portuguese traders.
Surprisingly, the history of tea consumption in India is much older than the Japanese or Europeans. Historical records from 750 BC indicate that tea was being grown and consumed by Indians as a vegetable. But, it was the British who began commercial tea cultivation in India and formally introduced Indians to the habit of drinking tea.
Today, tea is grown in 40 countries around the world. However, China, India, Kenya and Sri Lanka contribute the most to the world's tea production.
Different types of tea
More than 3,000 different types of tea are grown around the world. However, based on how the tea leaves are processed, all the types fall under any one of the following six categories:
- White tea
- Black tea
- Green tea
- Yellow tea
- Oolong tea
- Pu'er tea
Is green tea different from other types of tea?
- As mentioned earlier, tea leaves are processed in different ways to produce the different types of tea.
- To produce green tea, leaves from the first harvest are usually used. These are believed to be of the best quality.
- The leaves are withered and then steamed or pan-fried. They are rolled and dried again. As a result, green tea tastes more natural than other types of tea.
- Green tea contains less caffeine compared to black tea. Because of this, drinking green tea does not produce the 'rush of adrenaline' usually experienced with drinking tea.
- Green tea contains high levels of catechin called epigallocatechin gallate (EGCG), one of the most powerful antioxidants.
- Green tea is more suitable for blending with other flavours such as chamomile, ginger and jasmine.
Types of green tea
Although it has its origin in China, as green tea benefits are now widely known, almost every tea-growing country is producing it. However, the consumption of green tea is the highest in Japan and China. Some of the popular green tea varieties are:
- Lu'An Gua Pian (China)
- Longjing/Dragonwell (China)
- Gunpowder (China)
- Biluochun (China)
- Huangshan Maofeng (China)
- Taiping Houkui (China)
- Xinyang Maojian (China)
- Sencha (Japan)
- Hojicha (Japan)
- Matcha (Japan)
- Genmaicha (Japan)
- • Gyokoro (Japan)
Nutritional value of green tea (1 cup)
- Water 239.83g
- Energy 2kcal
- Protein 0.53g
- Saturated fatty acids, total (g) 0
- Copper 0.01mg
- Iron 0.05mg
- Magnesium 2mg
- Potassium 19mg
- Sodium 2mg
- Zinc 0.02mg
- Vitamin C 0.7mg
- Vitamin B-6 0.012mg
- Niacin 0.072mg
- Riboflavin 0.139mg
- Thiamin 0.017mg
- Caffeine 29mg
Data based on Agricultural Research Service (ARS), United States Department of Agriculture (USDA)
Health benefits of green tea
Apart from ancient herbalists and practitioners of traditional medicine, even modern research has proved the many health benefits of green tea. Let's look at some of the ways drinking green tea can work wonders for your health:
- Promotes weight loss: Drinking organic green tea for weight loss is a very popular practice. But, how true is this belief? Shixian et al mention that many reports have associated the intake of green tea extract with an increase in weight loss. They attribute this to the presence of EGCG, which promotes diet-induced thermogenesis.
- Reduces risk of cancer: Green tea is a rich source of compounds that fight different types of cancer such as that of the lung, breast, oesophagus and prostate. EGCG and epigallocatechin (EGC) present in green tea rid the body of free radicals. Other polyphenols present in tea inhibit the damage caused by ultraviolet B radiation and the proliferation of tumour cells. They also have detoxifying properties, which protects the body from developing tumours.
- Lowers cholesterol: One of the many advantages of drinking green tea is that it lowers the bad cholesterol (LDL) and increases good cholesterol (HDL). In combination with a heart-friendly diet, green tea cuts down the risk of developing heart disease. According to a study by Khan and Mukhtar, drinking green tea decreases the absorption of triglycerides.
- Decreases risk of stroke: Green tea contains tannins, theaflavins and thearubigins — all of which promote good health by reducing blood pressure and boosting cardiovascular function. Research shows that a reduction of systolic blood pressure by 5 mmHg and diastolic blood pressure by 2 mmHg cuts down the risk of cardiovascular event or stroke by 13 and 12 per cent, respectively.
- Benefits people with diabetes: A rapidly emerging health challenge before the world is the increasing number of diabetic patients. According to the National Health Portal, in India, around 60 million are affected by diabetes, a condition that can’t be cured but only controlled. Research has shown that green tea increased glucose metabolism and produced antihyperglycemic effects in type 2 diabetes patients.
- Reduces risk of neurodegenerative diseases: Green tea benefits in neurodegenerative conditions such as cognitive dysfunction and memory loss are becoming apparent. According to Pervin et al, many studies have reported the preventive effect of green tea on Parkinson's disease.
- Fights cold and flu: The common cold is perhaps the most common disease. From the elderly to the very young, it affects everyone. There are many viruses which can give rise tocause thise diseasecondition and; however, there is no cure yet. Adults suffer at least 2–3 bouts of common cold per year and children around 12. However, consuming green tea regularly can decrease the rate of occurrence of cold and influenza.
- Decreases risk of arthritis: A life-changing disease which places limits on physical activity, arthritis also causes pain. According to the Arthritis Foundation, drinking green tea can reduce inflammation and cartilage destruction. In their study, Alghadir et al found that "Cclinical improvements in disease activity, health quality, and bone resorption and formation biomarkers were observed in all RA patients following green tea and exercise therapy interventions."
- Protects from skin diseases: The benefits of drinking green tea for benefits the skin include by offering protection from ultraviolet B rays-induced disorders. These include melanoma and nonmelanoma skin cancers, and photoaging. The polyphenols present in green tea play a big role in inhibiting photocarcinogenesis (UV rays-induced skin cancer).
How to prepare green tea
The taste of green tea depends a lot on the type of water, temperature of water and brewing time.
- It is best to use soft water, as it is low in calcium and other minerals.
- Once you begin heating the water to prepare green tea, it is important to pay attention to the temperature. If you heat the water too much, the tea would taste bitter, and if you do not heat the water to the optimum temperature, the flavours wouldn't come out. For best results, keep the water temperature between 140 to 185 degrees Fahrenheit. The amino acids present in green tea dissolve at 140 degrees whereas the tannins dissolve at 170 degrees.
- Once the water is hot enough, pour it into the teapot containing the tea leaves. Allow 1 to 2 minutes to pass before pouring it for consumption.
How much green tea should you drink?
Both science as well as traditional knowledge support the health advice, 'Everything in moderation.' So, when it comes to drinking green tea, how much should you have? In a study conducted by Mousavi et al, it was found that drinking four4 cups of green tea every day caused a significant reduction in body weight, body mass index and systolic blood pressure.
Green tea side effects
Although green tea is widely known for its beneficial effects on health, there are some side effects of overconsuming it as well.
- Green tea has caffeine. So, when it is consumed in large quantities, the intake of caffeine increases and causes insomnia, restlessness and diarrhoea.
- Green tea has diuretic properties. So, overconsumption can cause excessive urination. This can result in dehydration and electrolyte imbalance.
- The tannins present in green tea can stain the teeth. They can bind with iron and interfere with iron absorption within the body, leading to problems like anaemia and weakness.
- Frequent consumption of hot green tea can result in asymptomatic erosive esophagitis.
- The caffeine present in green tea can interfere with the absorption and effect of certain some types of medications (such as blood thinners and lithium).
Interesting green tea facts
- Green tea is the least processed type of tea.
- It is considered one of the most healthiest drinks.
- Only 20% of tea consumed globally is green tea.
- Green tea contains 20-45 per cent polyphenols by weight.
- Before the 14th century, green tea was only available to the highest elite sections of the Chinese society.
- Black tea was created much later after green tea, in the 16th century.
About the author:
Written by Arun Sharma on 28 Oct 2019
The author was associated with the healthcare industry before becoming a full-time writer and editor. A doting father to two preteens, he believes in experiential learning for his children. Also, he loves mountain trekking and nature trips.
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