Types of Teas and Their Health
Benefits
From green tea to hibiscus, from white tea to
chamomile, teas are chock full of flavonoids and other healthy goodies.
By Julie Edgar
WebMD Feature
Reviewed by Louise
Chang, MD
Regarded for thousands of years in the East as a
key to good health, happiness, and wisdom, tea has caught the attention of
researchers in the West, who are discovering the many health benefits of
different types of teas. Studies have found that some teas may help with
cancer, heart disease, and diabetes; encourage weight loss; lower cholesterol;
and bring about mental alertness. Tea also appears to have antimicrobial
qualities. “There doesn't seem to be a downside to
tea,” says American Dietetic Association spokeswoman Katherine Tallmadge, MA,
RD, LD. “I think it’s a great alternative to coffee drinking. First, tea has
less caffeine. It’s pretty well established that the compounds in tea – their
flavonoids – are good for the heart and may reduce cancer.” Although a lot of questions remain about how long
tea needs to be steeped for the most benefit, and how much you need to drink,
nutritionists agree any tea is good tea. Still, they prefer brewed teas over
bottled to avoid the extra calories and sweeteners. Here's a primer to get you started.
Health Benefits of
Tea: Green, Black, and White Tea
Tea is a name given to a lot of brews, but purists
consider only green tea, black tea, white tea, oolong tea, and pu-erh tea the
real thing. They are all derived from theCamellia sinensis plant, a
shrub native to China and India, and contain unique antioxidants called
flavonoids. The most potent of these, known as ECGC, may help against free
radicals that can contribute to cancer, heart disease, and clogged arteries.
All these teas also have caffeine and theanine,
which affect the brain and seem to heighten mental alertness.
The more processed the tea leaves, usually the less
polyphenol content. Polyphenols include flavonoids. Oolong and black teas are
oxidized or fermented, so they have lower concentrations of polyphenols than
green tea; but their antioxidizing power is still high.
Here's what some studies have found about the
potential health benefits of tea:
·
Green tea: Made with steamed tea leaves, it has a high
concentration of EGCG and has been widely studied. Green tea’s antioxidants may
interfere with the growth of bladder, breast, lung, stomach, pancreatic, and
colorectal cancers; prevent clogging of the arteries, burn fat, counteract
oxidative stress on the brain, reduce risk of neurological disorders like
Alzheimer’s and Parkinson’s diseases, reduce risk of stroke, and improve
cholesterol levels.
·
Black tea: Made with fermented tea leaves, black tea has the
highest caffeine content and forms the basis for flavored teas like chai, along
with some instant teas. Studies have shown that black tea may protect lungs
from damage caused by exposure to cigarette smoke. It also may reduce the risk
of stroke.
·
White tea: Uncured and unfermented. One study showed that
white tea has the most potent anticancer properties compared to more processed
teas.
·
Oolong tea: In an animal study, those given antioxidants from
oolong tea were found to have lower bad cholesterol levels. One variety of
oolong, Wuyi, is heavily marketed as a weight loss supplement, but science
hasn’t backed the claims.
·
Pu-erh tea: Made from fermented and aged leaves. Considered a
black tea, its leaves are pressed into cakes. One animal study showed that
animals given pu-erh had less weight gain and reduced LDL cholesterol.
Health Benefits of
Tea: Herbal Teas
Made from herbs, fruits, seeds, or roots steeped in
hot water, herbal teas have lower concentrations of antioxidants than green,
white, black, and oolong teas. Their chemical compositions vary widely
depending on the plant used. Varieties include ginger, ginkgo biloba, ginseng,
hibiscus, jasmine, rosehip, mint, rooibos (red tea), chamomile, and echinacea. Limited research has been done on the health
benefits of herbal teas, but claims that they help to shed pounds, stave off
colds, and bring on restful sleep are largely unsupported.
Here are some findings:
· -
Chamomile
tea: Its antioxidants may help prevent complications from diabetes, like loss
of vision and nerve and kidney damage, and stunt the growth of cancer cells.
·
-Echinacea:
Often touted as a way to fight the common cold, the research on echinacea has
been inconclusive.
· -
Hibiscus:
A small study found that drinking three cups of hibiscus tea daily lowered blood
pressure in people with modestly elevated levels.
· -
Rooibos
(red tea): A South African herb that is fermented. Although it has flavonoids
with cancer-fighting properties, medical studies have been limited.
Health Benefits of
Tea: Instant teas
Instant tea may contain very little amounts of
actual tea and plenty of sugars or artificial sweeteners. For health’s sake,
check out the ingredients on the label.
Can Tea Be Bad for
Your Health?
Most teas are benign, but the FDA has issued
warnings about so-called dieter’s teas that contain senna, aloe, buckthorn, and
other plant-derived laxatives. The agency also warns consumers to be wary of
herb-containing supplements that claim to kill pain and fight cancer. None of
the claims is backed by science and some of the herbs have led to bowel
problems, liver and kidney damage, and even death. The FDA cautions against taking supplements that
include:
·
-Comfrey
· -
Ephedra
·
-Willow
bark
·
-Germander
· -
Lobelia
· -
Chaparral
These cautions aside, nutritionists say to drink up
and enjoy the health benefits of tea.
“You want to incorporate healthy beverages in your
diet on a more regular basis to benefit from these health-promoting
properties," says Diane L. McKay, PhD, a Tufts University scientist who
studies antioxidants. "It’s not just about the foods; it’s about what you
drink, as well, that can contribute to your health."
