 |
|
Tea: “Ask The Expert” Column
|
By Liz Pearson
I used to drink coffee, but recently switched to tea. What are the health benefits?
Good move: while coffee consumed in moderation (one to two cups daily) doesn't appear to be harmful to health and may even have some benefits, accumulating research suggests that tea may give your health a better boost.
Tea types
There are a number of different types of tea, but here I'm referring to black tea, which is popular in North America, and green tea, which is more common in Asian countries. Both are rich in plant compounds called flavonoids. Flavonoids appear to help protect health by acting as antioxidants in the body and by helping to prevent free radicals from damaging body cells. The flavonoids found in black and green tea are different due to the way each tea is processed (black tea is fermented, green is not). While both teas may be beneficial, preliminary research suggests that green tea may offer greater protection from disease, especially cancer, than black tea.
Tea for your heart
A recent review of 17 studies by the University of North Carolina School of Public Health linked the daily consumption of three cups of tea to an 11 per cent lower heart attack risk. Why? The Rotterdam Study from the Netherlands involving over 3,400 women and men, found that black tea (especially at an intake of more than four cups daily) was associated with significantly less plaque build-up on artery walls. In a study from the Boston University School of Medicine, drinking four cups of black tea daily helped dilate arteries and significantly improve the blood flow of 50 men and women suffering from heart disease.
Tea kills cancer cells
In a study from the Curtin University of Technology in Australia, involving over 900 women from China, the risk of ovarian cancer was found to be about 60% less in daily tea drinkers, especially green tea drinkers, as compared to non-tea drinkers. In a study from the Saitama Cancer Center Research Institute in Japan, involving almost 500 women treated for breast cancer and monitored for seven years, the risk of breast cancer returning was significantly less in those regularly consuming green tea, especially at a level of more than five cups daily. Tea's role as a cancer fighter appears to come in part from its ability to cause cancer cells, once formed, to die.
In the works
Preliminary research suggests that tea may reduce joint inflammation, slow cartilage breakdown, and help keep bones strong. In the Iowa Women’s Health Study involving over 30,000 women, those consuming more than three cups of tea daily were about 60% less likely to develop rheumatoid arthritis. Tea (consumed without milk or sugar) may also help fight cavities and prevent gum disease by killing or suppressing cavity-causing bacteria.
Tea tips
Although the research on tea is still in the early stages, I recommend that you drink about three to six cups of green or black tea daily. To get the greatest health benefit from your tea, keep these tips in mind.
- To maximize the amount of flavonoids released from tea, brew it for at least three to five minutes (85% of antioxidants are released within this time). Continuously dunking the tea bag can increase the amount of flavonoids released by as much as five-fold.
- A typical cup of black tea contains 45 mg of caffeine, while green tea contains about 30 mg (a cup of coffee about 125 to 150 mg). Most experts consider 300 to 400 mg of caffeine as a safe and moderate daily intake. Because the flavonoid content of decaffeinated tea may be significantly less (as much as 50% less), drinking regular tea is generally a healthier choice.
- If you like iced tea, make your own. When tea is processed into powdered or bottled liquid form, the flavonoid content is often decreased.
- Don't drink tea scalding hot - it may increase your risk of cancer of the esophagus.
- If you have trouble meeting your need for iron, drink tea between meals or one hour after meals. Black tea in particular can significantly inhibit the absorption of non-heme iron (iron that comes from plant sources like bread or cereal).
|
|
 |
