Green tea is a special type of tea made from the leaves of Camellia sinensis. It is mainly originated in China and prepared by unoxidized leaves and involves less processing. Green tea is composed of several health promoting substances and its daily consumption is related with reducing the risk of developing several diseases.

Nutritional profile

• Green tea contains several vitamins like Vitamin A, Vitamin E, Vitamin C, riboflavin and folic acid
• It also contains several minerals such as calcium, phosphorus, potassium, manganese and fluorine
• It contains chlorophyll which is responsible for providing deodorizing effect
• It is rich in polyphenols which make it more health worthy especially by exerting antioxidant and anti-inflammatory effects. The most important polyphenolic compounds of green tea include catechin, epicatechin, epigallocatechin, epigallocatechin gallate and epicatechin-3-gallate. These compounds are also accountable for providing astringency and bitterness of green tea
• It also contains saponins, which have an anti-influenza effect and helps to prevent hypertension

Why consumption of green tea is better than black tea

Consumption of green tea is healthier than black tea due to its processing mechanism. Mechanism of black tea processing involves fermentation, on a contrary, processing of green tea does not involve any fermentation process. Hence, green tea comparatively retains more polyphenols and antioxidants than black tea. This phenomenon makes it comparatively healthier

Health benefits

Role on metabolism and weight reduction

• Green tea helps to increase metabolism
• The polyphenol components of green tea are responsible for enhancing fatty acid oxidation that enhances calorie expenditure of body in many folds and leads to weight reduction. Hence, green tea is considered as an effective therapeutic substance for preventing obesity

Role on cardiac health

• Catechins of green tea have antioxidative, anti-inflammatory, anti-hypertensive, antithrombogenic and anti-proliferative properties that help to protect the entire cardiovascular system
• Basically, it helps to improve lipid profile by reducing lipid absorption and by inhibiting enzymatic action responsible for fatty acid biosynthesis. Healthy lipid profile helps to maintain the ratio of LDL and HDL and prevents the susceptibility of atherosclerosis
• The antioxidant property of green tea is responsible for scavenging free radicals that helps to reduce their concentration and reduces oxidative damages of heart. It also protects the LDL from oxidation and hence reduces the risk of developing cardiovascular diseases
• It also helps to reduce hypertension
• It helps to prevent clot formation within blood vessels and promotes adequate blood circulation

Role on preventing diabetes

• It has seen that green tea helps to reduce the risk of diabetes mellitus (type -2)

• It helps to regulate blood sugar concentration by increasing insulin sensitivity

Role on skin

• Green tea also helps to improve skin health. It is associated with preventing wrinkles
• The catechins component of green tea acts as strong antioxidant and helps to slow down the ageing process

Role on preventing cancers

• Free radicals are responsible for increasing oxidative stress of body that lead to develop various diseases including cancers. Consumption of green tea is related with reducing the oxidative stress as it is rich in antioxidant
• It has seen that green tea especially helps to reduce the risk of prostate, breast, esophageal and colorectal cancers

Role on promoting brain functions

• Caffeine of green tea is accountable for promoting brain functions. Though green tea contains very less amount of caffeine (compared to coffee) but it acts as a strong stimulant
• Caffeine blocks adenosine (an inhibitory neurotransmitter) and helps to enhance the concentration of dopamine and norepinephrine which are related with boosting up neurological functions, improving mood, vigilance and memory
• L-theanine (an amino acid) content of green tea also helps to promote brain functions by increasing the production of alpha waves within brain

• Green tea helps to prevent dementia, Alzheimer’s disease and Parkinson’s disease

Disease preventing roles of green tea

Green tea extract for different diseases

• Several researches and studies have shown that epigallocatechin-3-gallate (EGCG), is an active component extracted from green tea, which has various significant effects on human health. It is associated with preventing vascularity, cancers, bone deformities and nervous disorders (Chu, 2017)
• EGCG has strong antioxidant, anti-inflammatory and anti-carcinogenic properties which help to prevent disease occurrence and associated with promoting oral health, vascular system and nervous system

Green tea and non-alcoholic fatty liver disease (NAFLD)

• Recent research has shown that consumption of green tea is an effective and safe alternative approach for treating non-alcoholic fatty liver disease (McLean, 2018)
• The polyphenol and flavonoid components of green tea are considered as the most promising substances, which are accountable for NAFLD treatment by reducing fat content, enzymatic activity and oxidative stress of the liver

Green tea and chronic inflammation

• It has seen that chronic inflammation is associated with debilitation, organ failure and losses of tissue activities. It is also associated with developing various disorders in body such as, neurodegenerative complications, hepatitis and gastrointestinal disorders. In severe condition these may lead to malignancy

• Several researches have been carried out on green tea and these have shown that polyphenol components of green tea help to prevent the consequences of inflammation by regulating signaling pathway of body (such as programmed cell death). It has seen that green tea polyphenols (GrTPs) play important role in secreting inflammatory markers like cytokines and cyclooxygenase-2 that help to prevent inflammation (Oz, 2017)

Green tea and Zika virus

• Zika virus is responsible for developing microcephaly in newborns and unavailability of proper drugs and vaccines is responsible for making the situation more worsen
• Recent research has shown that epigallocatechin-3-gallate (EGCG) component of green tea has a strong antiviral activity and it is capable of inhibiting about 90% of the entry of Zika virus and helps to prevent its consequences. Hence it may be used as an effective preventive measure against Zika virus (Carneiro et al., 2016)

Green tea and metabolic disorders

• Polyphenol components of green tea especially catechin, epigallocatechin-3-gallate and epicatechin gallate are responsible for preventing metabolic syndromes like obesity, diabetes, cardiovascular diseases and hypertension
• It has seen that daily consumption of green tea is coupled with stimulating the catabolic and anabolic reactions of body and helps to promote overall health

General consideration

• As mentioned above, green tea consumption is advantageous for health, but it should be kept in mind that its consumption should be avoided at bedtime as its caffeine contents (act as strong stimulant) may interfere with sleep

• It is safe to consume about 3 to 5 cups of green tea, but excessive consumption is harmful as catechins of green tea interfere with iron absorption in excessive amount
• Individual who use green tea especially for weight reduction should consume it before exercise as EGCG component of green tea helps to increases oxidation rate of fatty acid
• It is better not to consume green tea along with meals, whereas it is wise to consume it in empty stomach
• Consuming green tea before or after 30 to 60 minutes of meal is best, as this timing is ideal for boosting up the metabolism at optimum level

Carneiro, B.M., Batista, M.N., Braga, A.C.S., Nogueira, M.L. and Rahal, P., 2016. The green tea molecule EGCG inhibits Zika virus entry. Virology, 496, pp.215-218.

Chawla, R., Goyal, S., Kaur, J., Rana, K., Arora, A. and Sahoo, U., 2017. GREEN TEA: A WHOLE BODY HEALTH TONIC: A REVIEW. Pharma Science Monitor, 8(4).

Chu, C., Deng, J., Man, Y. and Qu, Y., 2017. Green tea extracts epigallocatechin-3-gallate for different treatments. BioMed research international, 2017.

Lorenzo, J.M. and Munekata, P.E.S., 2016. Phenolic compounds of green tea: Health benefits and technological application in food. Asian Pacific journal of tropical biomedicine, 6(8), pp.709-719.

McLean, W., 2018. Green tea as a safe treatment for non-alcoholic fatty liver disease. Australian Journal of Herbal and Naturopathic Medicine, 30(4), pp.192-194.

Oz, H.S., 2017. Chronic inflammatory diseases and green tea polyphenols. Nutrients, 9(6), p.561.

Reygaert, W.C., 2017. An update on the health benefits of green tea. Beverages, 3(1), p.6.

Saraswat, A.G., 2018. Health benefits of green tea versus black tea. Health, 3(3).