A group of researchers have warned that too much consumption of green tea is unhealthy and might harm the health.
Green tea is consumed most popularly as beverage all over the world. And, although there are beneficial effects of green tea, it also has side effects, according to the researchers, who both teach at the Jinnah University for Women in Karachi, Pakistan.
Again, various research articles warn that by consuming large amounts of green tea nausea, vomiting, dehydration, lethargy, central nervous system stimulation such as dizziness, insomnia, tremors, restlessness, confusion, diuresis, heart rate irregularities and psychomotor agitation may occur.
Most side effects are due to high consumption of caffeine. In particular, researchers have focused attention on Epigallocatechin-3-gallate. The EGCG – the most abundant catechin in tea – is a polyphenol under basic research for its potential to affect human health and disease.
Nutritionists say that green tea has anti-folate activity; as such, it should not be taken in excessive quantity in order to prevent folate deficiency. It may also react with some drugs such as aspirin and MAOI class of drugs when consumed too much.
Indeed, researchers say that some categories of people should avoid green tea consumption altogether. These include pregnant and lactating mothers, as well as people living with hypertension due to the medications they might be taking.
In addition to these warnings, experts at online portal WebMD note that too much consumption of green tea might cause the following health issues:
Research papers cited variously by WebMD, Medical News Today and others note that in general, anaemia results from iron deficiency. However, green tea contains a pigment named epigallocatechin gallate (EGCG), which binds iron in the blood, reducing iron content. As a result, it prevents iron absorption, leading to iron deficiency and reducing your haemoglobin count. Low haemoglobin levels may result in breathlessness, fatigue, and weakness.
Nutritionists warn that caffeine in green tea stimulates the nervous system. The stimulation makes you rejuvenated and fresh. However, caffeine interacts with certain medications. As a result, it leads to adverse effects or complications.
Usually, caffeine breaks down and gets eliminated from your body. However, studies reveal that some medications prevent their breakdown. Instead, they cause the accumulation of caffeine in your body. It elevates the adrenalin levels in your body, which can potentially shoot up your blood pressure and heart rate. Such medications include antibiotics, birth control drugs, and anaesthetics.
Caffeine also prevents the action of certain antipsychotic drugs like Clozapine, Metazolam, and Lithium content drugs. As a result, it prevents absorption, resulting in drug accumulation in the blood. As per research, such drug accumulation results in clozapine toxicity and can also cause lithium toxicity.
Vitamin K in green tea also interferes with the effects of Warfarin, an anticoagulant or anti-blood-clotting drug. As a result, it can initiate bleeding in patients with bleeding disorders.
Triggers Inflammatory Bowel Diseases (IBD)
You should avoid drinking green tea if you have IBD. That is because the EGCG binds with iron in your body and restricts the inhibition of an enzyme named myeloperoxidase.
The enzyme triggers inflammation in inflammatory bowel diseases. As a result, it causes inflammation and other symptoms, including stomach pain and vomiting.
Harmful during pregnancy
During pregnancy, excessive green tea consumption may impact both the mother and the foetus. It causes hypertension in mothers and increases the heart rate, researchers claim. Both conditions are harmful.
Caffeine also increases urination, resulting in possible dehydration.
Blood pressure may exert force on the heart and kidney, resulting in disorders. Blood pressure might also cause contractions in the uterus, resulting in preterm delivery.
Caffeine and tannins in green tea can also lower the folic acid content in a pregnant woman’s body. Yet, folic acid is vital during pregnancy because it prevents anaemia and also prevents any changes in DNA, among others.
Folic acid also prevents newborn abnormalities like spina bifida, a congenital deformity.
Epigallocatechin gallate (EGCG), a pigment in green tea, imparts various health benefits. However, excess concentration makes the liver release enzymes to break down or metabolise caffeine. This exerts a load on the liver and disturbs its smooth functioning.
The caffeine content harms the liver cells and results in liver toxicity, which can cause jaundice and urine discoloration. Symptoms of liver toxicity include headache, dizziness, and palpitations.
Impacts bone strength
Flavonoids are essential for bone growth. However, higher doses impact bone growth and density. In addition, the caffeine in green tea might restrict calcium absorption, which results in low calcium levels in the bone. Calcium is the central element for bone health.
Calcium deficiency affects bone growth and strength, increasing the risk of fractures and reducing bone density.
May cause infertility in men
In a 2018 study at the University of California-Irvine, researchers warn that excessive consumption of green tea may adversely affect fertility.
That is due to the flavonoids in green tea. Though these flavonoids are beneficial to health, researcher say an excess causes impaired sperm synthesis and sperm motility and decreases testosterone levels.
Testosterone is the male reproductive hormone. In addition, caffeine impacts the DNA in sperm, affecting sperm viability and impacting reproduction.
Quantity of green tea to drink daily
Every food or drink has one side effect or the other and green tea is not different. Unfortunately, along with the beneficial side of green tea, side effects also persist. However, experts say trouble only happens when you over-consume it. So, drink green tea in moderation. Anything under two cups per day is safe, experts say.