Doctors usually advise against the consumption of alcohol, tobacco, coffee and tea. But a patient asked me during consultation: “How many cups of tea should I give my kids each day?” Before I could comprehend what he was saying, he waved a copy of The Hindu (Oct. 10, 2013, Coimbatore edition), which quoted an official of the Tea Board as saying: “The benefits of tea on the health front should be widely propagated.” An office-bearer of an organisation was also quoted as saying that a series of meetings would be held with the help of the Tea Board to promote tea-drinking among children.
The Tea Board has often urged the public to drink more tea to lower the risk of heart disease, stroke and cancer (The Hindu, Sept. 25, 2001), quoting scientific literature on the value of tea in protecting people from these diseases, but conveniently ignoring literature on the possible and proven adverse effects of excessive tea consumption.
Green tea, black tea, white tea, oolong tea, pu-erh tea, and so on are all derived from the plant Camellia sinensis, native to China and India. Tea has for long been considered to be a healthy drink full of flavonoids and other goodies like antioxidants that have a variety of positive health benefits — reducing risk of cardiovascular diseases, stroke, cancer, obesity, infections, osteoporosis, hypertension, neurological disease, cognitive impairment, and so on. Scientific literature carries evidence in favour of tea, especially green tea which has more than 30 polyphenols and a catechin called epigallocatechin (EGCg) which act on the human system in positive ways.
How much of this evidence is created by “paid research” is a different question. Industry has a big stake as after water, tea is the most widely consumed beverage, and as there does not seem to be a downside to tea. But some studies indicate that excessive consumption of tea or tea-based dietary supplements may cause osteoporosis, Alzheimer’s Disease, digestive disorders, premenstrual syndrome, cardiovascular problems, urinary system disturbances, sleeplessness, kidney stones, oesophageal cancer, nervous disorders, and so on.
Adverse effects are caused by the presence of fluoride, aluminium, tannins, oxalates, caffeine, and so on in tea leaves, especially in those that are not hand-picked and are machine-processed. Caffeine-related side-effects are more pronounced in children even when consumption is in small doses. Canadian guidelines recommend that young children should not get more than 45 mg of caffeine a day.
A study by Jashua Lambert et al at Rutgers University, funded by the National Institutes of Health, revealed that excessive consumption of tea or tea-based products could cause chromosomal damage, foetal leukaemia and liver damage. One commercial brand of green tea extract was found to contain excessive levels of polyphenols, or plant-based antioxidants, whereas a cup of green tea has only about 8 mg.
Another study led by Dr. Kashif Shafique of Glasgow University found that the risk of getting prostate cancer is 50 per cent more in men who drank more than seven cups of tea a day, compared to those who consumed less.
All the negative evidence is drowned in the cacophony of aggressive marketing propaganda. Nowadays, even in the medical field, industry seems to define the diagnostic and treatment options — through controlled and sponsored (read ‘paid’) research.
Business promoters often use scientific observations selectively to mislead the public and augment the sale of their products. One may quote from the Journal of the American Medical Association (June 1999), and the “Nurses’ Health Study” and “Physicians’ Health Study” and appeal to the public to drink more coffee to lower the risk of gallstones, and to drink alcohol daily to protect against heart attacks and bad cholesterol levels.
No doubt, tea leaves are generally and nutritionally good, like many other leaves we use in our diet, but the tall claims are commercially motivated. A little tea may be good, but it is unduly glorified by business. And now it seems it makes business sense to get children addicted to tea. They are already victims of irresistible commercial junk food that is unfit for human consumption.
There is no conclusive scientific evidence that tea, including ‘green tea’, reduces the risk of coronary artery disease, stroke, cancer or early death due to any cause. The U.S. National Cancer Institute “does not recommend for or against the use of tea to reduce the risk of any type of cancer.”
Dissemination of imbalanced information does more harm than good. And if a little tea is good, more of it need necessarily not be better. So, take the Tea Board’s words with a pinch of salt.
(The writer is a Respirologist at the Pay What You Can Clinic, Perundurai, Tamil Nadu. He earlier served at the Perundurai Medical College & Research Centre. E-mail: drtramaprasad @gmail.com )