Tea and Scientific Research - The benefits of drinking tea

White Tea

March 11, 2003 -- Perhaps you've never heard of white tea. But there's evidence pointing to the health benefits of green tea and white tea. They may help prevent colon cancer.

Antioxidants and polyphenols -- cancer prevention compounds -- are found in highest levels in white tea, which is the least processed of all teas, writes lead author Gayle. A. Orner, PhD, a researcher with the Linus Pauling Institute at Oregon State University.

White tea is relatively rare and is found in specialty tea shops, over the Internet, and in some grocery stores. Green tea, which undergoes some processing, has higher polyphenol levels than black tea, which gets the most processing, Orner says.

Her study of teas' protective effects against colon cancer appears in the February issue of Carcinogenesis.

In a study involving mice, Orner and colleagues tested the benefits of green tea, white tea and a drug called sulindac, which is a nonsteroidal anti-inflammatory (NSAID) that, like high-dose aspirin, has been shown to prevent progression of colon cancer and decrease the death rate.
Orner's study used mice that were genetically predisposed to develop tumors in their intestines.
After 12 weeks of treatment, mice that were given white tea, green tea, or low-dose sulindac had significantly fewer tumors than mice that received no treatment.

Mice that received no treatment developed about 30 tumors. Those that consumed green tea had an average of 17 tumors. Mice given white tea had 13 tumors. Mice given both sulindac and white tea had 80% fewer tumors -- an average of six.

It's evidence that tea's effects on metabolism can potentially block some cancer-causing effects, she explains. In fact, the concentrations of tea the mice got were comparable to those consumed by humans, she says.

"Therefore, this widely consumed beverage may be useful in the prevention of intestinal cancer in genetically predisposed individuals," she writes.

"These are pretty exciting results," Orner says in a news release. "What's especially significant is that as far as we can tell, consumption of tea has none of the side-effects of NSAIDs, which can be severe, including bleeding, ulcers, and even death."

The use of NSAIDS for cancer prevention, heart disease, and other concerns is increasingly common with many people, and high aspirin intake has been associated with a 40% to 50% decrease in death from colon cancer, she notes in her paper.

To get the same colon cancer-prevention benefits of green tea or white tea, drink about three mugs of tea daily, she says. This is based on studies in Japan with green tea and gastric cancer, where researchers essentially concluded "the more, the better."

Green Tea and Arthritis

Winter time anti-inflammatory advice - warm up with green tea, Green tea for our joints.Many have heard about the health benefits of green tea, particularly inthe context of preventing cancer and heart disease. It also has athermogenic effect, so it is good for those who wish to lose weight.As joint health is one our main interests as chiropractors, it isinteresting to note that green tea has been shown to be effective ininhibiting the development of arthritis is experimental models. The wayresearchers study arthritis in animal models is to chemically inducearthritis with various substances. Then animals are given differentpotential anti-inflammatory drugs or supplements to examine the outcomeon the progression of arthritis.In one interesting study, researchers gave mice green tea polyphenols tomice in water, which basically equates with the green tea extracts thatare found in supplements. Of the mice given the green tea extract, theincidence of arthritis was 33% to 50%, compared to an incidence of 84%to 100% in the mice who did not receive green tea supplementation (1).Exactly how much green tea we should drink or the amount we should takein supplement for is not known for sure. I try to drink at least 3-4 cupsper day. Many of the excellent newer flavonoid and anti-inflammatorysupplements contain green tea extracts.The polyphenols in green tea, which are part of the bioflavonoid family,are known as catechins. The key catechin in green tea isepigallocatechin-3-gallate or EGCG for short.What if you or your patients don't want to make or drink green tea? Takesupplemental green tea extracts.Haqqi TM et al. Prevention of collagen-induced arthritis in mice by apolyphenol fraction from green tea. Proc Natl Acad Sci 1999; 96:4524-29Tea Protects against Osteoporosis

April 13, 2000 (Atlanta) -- Ladies, start your teapots! A new study from England shows that tea may build and strengthen bones -- protecting women against osteoporosis. If milk is added to the tea, the benefit is boosted even more.

Although several studies have cited caffeine intake a risk factor for osteoporosis and hip fracture in women, at least two European studies have reported that tea drinking protected against hip breaks.

The current study shows that "the magnitude of the effects of drinking tea was notable," writes lead author Verona M. Hegarty, PhD, a gerontology researcher at England's University of Cambridge School of Medicine. Older women who drank tea had higher bone mineral density measurements, an indicator of bone health, than those who did not drink tea. "Nutrients found in tea ... [may] protect against osteoporosis in older women," concludes Hegarty.
Her study, which involved over 1,200 women living in Cambridge, is published in this month's issue of the American Journal of Clinical Nutrition.

The women completed questionnaires regarding their health and lifestyle that included questions on daily tea and coffee consumption, smoking habits, physical activity, alcohol intake, whether they drank caffeinated or decaffeinated coffee, whether coffee was instant or ground, whether they used hormone replacement therapy, if they added milk to tea, and so on. Each also had their bone mineral density measured, which showed bone strength in the spine and the area where hip breaks most often occur.

Among the women, there were over 1,100 tea drinkers and just about 120 non-tea drinkers, all between the ages of 65 and 76.

Tea drinkers had significantly greater bone mineral density measurements. Among coffee drinkers, those who also drank tea had significantly higher measurements as well.
"These findings were independent of smoking status, use of hormone replacement therapy, coffee drinking, and whether milk was added to tea," says Hegarty. Also, number of cups of tea per day did not seem to play a role, and women who added milk to their tea had much higher bone mineral density in the hip area.

Though more study is needed, Hegarty suggests that tea has components that weakly mimic the effect of the female hormone, estrogen -- documented by other researchers -- and may be important in maintaining bone mineral density in postmenopausal women. Hegarty writes that tea's attributes may have little effect in younger women and men but may be important in keeping bones healthy in older women.

"This research presents some interesting findings," Pamela Meyers, PhD, tells WebMD. "Most research on teas, especially on green tea, has looked at its ability to lower risks of cancer and heart disease. This is the first I have seen that has researched the effects of tea on BMD." Meyers is a clinical nutritionist and assistant professor at Kennesaw State University near Atlanta.

However, says Meyers, she would like to see more complete data on intake of animal protein, calcium, caffeinated sodas and exercise -- all factors that can affect bone density. She reminds women that high consumption of protein and sodas may increase risk of osteoporosis, whereas extra calcium and exercise can improve bone density. "I would like to see more studies into the [estrogen effects] of tea, both green and black," she says.

Vital Information:

Scientific research has shown that caffeine consumption increases the risk of osteoporosis, but a new study shows that tea may actually offer a protective effect against the disease.
In a British study, women who consumed tea had significantly greater bone mineral density when compared to non-tea drinkers.

Researchers suspect that substances in tea can mimic the effects of estrogen in protecting bones.