Coffee vs. tea
When it comes to health, which is a better choice--coffee or tea?
By Rosie Schwartz
First published in Chatelaine's August 1998 issue.
©Rosie Schwartz
Both brews have been at the centre of much scientific research. If you're concerned about your caffeine intake, keep in mind that the amount varies greatly--a cup of drip coffee has about three times the caffeine of regular tea (includes green, black and oolong types). While caffeine can cause some health problems, it's not the only substance in tea and coffee that can affect your health (we'll consider the health claims of herbal teas in a future column).
Before you opt for one over the other, consider some of the risks and benefits:
- The cardio connection
Over the years, coffee has been linked periodically to an increased risk of cardiovascular disease. A recent study of 16,000 adults published in the American Journal of Clinical Nutrition supports this link. Researchers at the University of Bergen, Norway, found that as coffee intake rose, so did the blood levels of homocysteine--an amino acid that can cause artery damage and increases one's risk for heart disease and stroke. Limiting your caffeinated coffee intake to a few cups a day may be wise since homocysteine levels increase with all preparations of coffee--filtered, boiled and instant--but are not affected by decaffeinated varieties. Smokers take note: coffee and cigarettes seems to be a particularly potent combination for boosting homocysteine levels.
Black, green and oolong teas' effect on heart health appears to be more positive. For example, the Norwegian homocysteine study found that as tea consumption rose, homocysteine levels decreased.
A number of other studies have shown that these teas can reduce the risk of developing cardiovascular disease. Researchers have found that the dietary flavonoids in tea, also abundant in fruits and vegetables, act as antioxidants in the body. They can help prevent the oxidization of cholesterol, reducing its chances of being deposited in the arteries. The way you prepare your tea may also affect its health benefits. Some research suggests that adding milk makes flavonoids harder to absorb. - Cutting cancer risk
These teas may also protect against certain types of cancer. Researchers at the University of Minnesota studied 35,000 postmenopausal women and found that as tea consumption rose, the rates of stomach, mouth and kidney cancers decreased. Recent animal studies suggest that drinking tea may offer some protection against skin cancer. Scientists surmise that the antioxidants in tea may counter the cell-damaging effects of compounds called free radicals, reducing the risk of a variety of cancers. - The fertility factor
Coffee consumption has also been linked to an increased risk of infertility and miscarriage. It's recommended that women who are pregnant or contemplating pregnancy practise moderation in drinking caffeinated coffee. Tea, however, is sometimes associated with increased fertility. While reasons for this connection are unclear, some research suggests that tea contributes to the development of healthy eggs. Or the link could simply be the result of tea drinkers' healthier lifestyles. - Tummy trouble
Both regular and decaffeinated coffee can cause indigestion. The culprit appears to be the acids in coffee beans, which increase gastric acid secretions, leading to stomach upset. - Bone breakers?
Although earlier research linked caffeine to an increased risk of bone loss, researchers at the University Hospital, Pennsylvania State University, found no significant link between drinking tea or coffee and increased bone loss in the group of postmenopausal women tested. - Snooze buttons
Caffeine's effects on sleep and irritability vary from person to person. Not only are there variations among coffee blends, but individual reactions to its stimulant effect depend on a person's weight and body size and other physiological factors--a cup may keep one person awake while another can down a double espresso after dinner and still sleep. Tea that contains caffeine may also affect your ability to sleep.
The bottom line ::::::
You're in luck if you're a tea lover since it provides plenty of health perks. If coffee is your beverage of choice, limit your intake to three cups a day and try cutting your caffeine intake by combining decaf and regular coffee in your brew.
Rosie Schwartz is a dietitian-nutritionist and author of The Enlightened Eater: A Guide to Well-Being Through Nutrition.