In a 15 June report, a World Health Organization panel of experts changed the status of coffee from “possibly carcinogenic” to a beverage whose regular drinking could possibly protect against at least two types of cancer. This report, which was published in the journal Lancet Oncology , must have come as a relief to those who can’t imagine life without coffee.
But there is ample research to suggest that coffee, which is loaded with caffeine, is not good for health when taken in excess.
Anil Chaturvedi, senior consultant (lifestyle diseases and preventive health) at the PSRI Hospital in New Delhi, says, “It (too much caffeine) may lead to insomnia, nervousness, restlessness, irritability, an upset stomach, a fast heartbeat and even muscle tremors.” But, then again, some studies suggest that this stimulant helps cut the risk of cancer, stroke, Parkinson’s disease and dementia.
Actually, the key lies in the quantity of caffeine we consume.
Caffeine is a natural chemical found in tea leaves, coffee beans, cacao (used to make chocolate) and cola nuts (the plant that gives cola soda its flavour).
It can also be produced synthetically and added to foods and beverages. Coffee and tea are the two most prominent sources of caffeine but it’s also found in chocolate, coffee ice cream, high-energy sports drinks and frozen yogurt. Iced tea too can contain as much sugar and caffeine as carbonated colas. According to the US food and drug administration and its National Soft Drink Association, about 340g, or 12 ounces, of ice tea has 47mg caffeine; a can of Red Bull, 80mg; a can of soft drink, 36-55mg; and (227g) green tea, 15mg. Many over-the-counter and prescription medications too contain caffeine.
The way to maximize its goodness is to have it in moderation. An adult can consume up to 400mg of caffeine a day without any harmful effect. A cup (250ml) of coffee contains 100mg of caffeine.
“Caffeine affects everyone differently. Some people are sensitive to 100mg of caffeine, so they need to be more careful as even small amounts (like a cup or two of coffee) may lead to restlessness and sleep problems. Plus, our tolerance levels for caffeine tend to decrease as we age and it has been noticed that men may be more susceptible to the effects of caffeine than women,” says Dr. R.K. Singal, Principal Consultant and Director of internal medicine at the BLK Super Speciality Hospital in New Delhi.
Most adults need 7-8 hours of sleep every day. Caffeine can interfere with this, blocking the brain molecules called adenosine that make us sleepy, says Dr Singal.
High caffeine consumption may lead to increased risk of bone thinning (osteoporosis), for it interferes with calcium absorption in the intestine.
Caffeine is also known to increase urinary excretion of calcium, magnesium, sodium, chloride and water, which may contribute to the weakening of bones, says Raju Vaishya, senior consultant (orthopaedics) and joint replacement surgeon at Indraprastha Apollo Hospitals in New Delhi
Caffeine is a diuretic. It causes the kidneys to release more water from the bloodstream, which causes the bladder to fill up more quickly. This can result not just in dehydration, but the loss of sodium and other vitamins and minerals. The symptoms could range from extreme thirst, headache and dizziness to constipation and muscle cramps, says Dr Chaturvedi.
Both women and men who consume a lot of caffeine are, in fact, 70% more likely to develop incontinence (a weak bladder).
In small quantities, caffeine can lead to higher levels of alertness and energy. Too much consumption, however, can lead to jitteriness, nervousness and headaches. And it can be addictive.
It promotes the production of two natural stimulants, dopamine and glutamine, which help lighten the mood and keep depression at bay, says Dr Singal.
It also sends a message to the brain, to tell the adrenal gland to flood the body with adrenalin that will make us energetic for some time.
Caffeine causes the heart to pump faster and quickens breathing, and the increased secretion of adrenalin increases the chances of arrhythmia (irregular heartbeat).
If you’re not a habitual coffee drinker, caffeine can raise blood pressure temporarily. This can be especially harmful for those suffering from hypertension.
Caffeine increases cholesterol and triglyceride blood levels, also risk factors in heart disease. It inhibits the enzyme phosphodiesterase, which interferes with the control of fat and blood glucose levels, leading to a marked and prolonged elevation of blood glucose and free fatty acids, says Nilesh Gautam, senior interventional cardiologist and head of the department of preventive cardiology and rehabilitation at the Asian Heart Institute in Mumbai. This, in turn, could raise cholesterol levels.
Caffeine may temporarily reduce appetite. It should never be had along with meals, for it can restrict the absorption of minerals like magnesium, zinc, potassium, calcium, sodium and other essential nutrients like carbohydrates, proteins and vitamins.
It can also raise acid levels in the stomach and may lead to heartburn and an upset stomach, says Dr Chaturvedi. People suffering from stomach ulcers and other gastro-problems should avoid caffeine.