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Green Tea: SIde effects and why you may need to avoid it

Diet Clinic 90% (1397 ratings)
B.Sc.(Hons), P.G.Dietetics
Dietitian/Nutritionist, Gurgaon,  •  15 years experience
Green Tea: SIde effects and why you may need to avoid it

Green tea has been promoted as one of the healthiest beverages around. It is made from the same kind of leaves (camellia sinensis) as generic black tea or oolong tea. The primary difference is that while processing the leaves for green tea, the withering and fermentation procedures are avoided, which helps the leaves retain more nutrients. However, green tea comes with quite a few side effects just like ordinary tea or coffee. They are:

1. Digestive problems
Since green tea is not put through the oxidation or fermentation process, the tannins present in the leaves are not removed. Tannins, can cause nausea and constipation by producing more gastric acid. Adding a little milk to your tea might help with this problem.

2. Reduced absorption of iron
Green tea contains catechins- antioxidants, which can block the absorption of iron from food. Iron deficiency has a number of negative impacts, the most threatening one being anemia where red blood cell formation is hindered. Anemia causes fatigue because sufficient oxygen is not circulated throughout the body due to low haemoglobin levels.

3. Problems with the nervous system
Green tea contains caffeine, just like tea or coffee, though its caffeine content is lower. Excessive consumption can lead to insomnia-like tendencies, heightened anxiety, frequent urination, irregular heartbeat, muscle cramps etc.

4. Risks during pregnancy
Caffeine decreases calcium content in the body, leading to weaker bones, which is an alarming symptom in an expecting mother. Also, caffeine, catechins and tannins are individually related to increased risks of miscarriage and other negative effects. Tannins and catechins passed on to breast milk can also block absorption of nutrients like proteins and fats in an infant's system.

5. Reactions with medication
Several chemical drugs are extremely reactive to the polyphenols in green tea, especially stimulant drugs like nicotine, ephedrin and amphetamine. Green tea reduces the functioning of lithium and dipyridamole. The polyphenols may also block the healing properties of the anti-cancer drug name bortezomib. Any kind of interference with your regular medication may impact your health adversely.

6. Negative impact on patients with glaucoma
The disease impairs the optic nerve and green tea increases the pressure on the eye within minutes of drinking it because caffeine accelerates intraocular pressure. The effects take more than an hour to subside.

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