Did You Know Just That Many Cancers Are Linked To A Vitamin Deficiency?
Evidence
show how vitamins prevent cancer
Vitamin
E protects against at least two common forms of cancer --
prostate and bladder -- but popping supplements is probably
not the best way to get the vital nutrient, researchers
said on Sunday.
Two
studies found that people who either ate the most vitamin
E containing food or who had the highest levels in the blood
were the least likely to have cancer.
But
the researchers also noted that there are several different
forms of vitamin E and the kind you eat -- in this case
alpha tocopherol -- is key. And the best-absorbed form of
alpha tocopherol is not found in supplements but in foods
such as sunflower seeds, spinach, almonds and sweet peppers.
In
one of the studies presented to the annual meeting of the
American Association of Cancer Research in Orlando, Stephanie
Weinstein of the U.S. National Cancer Institute and colleagues
found men with the most vitamin E in their systems had the
lowest risk of prostate cancer.
They
looked at data from 29,133 Finnish men aged between 50 and
69 taking part in a smoker's study. All gave blood at the
beginning of the study and then took vitamins to see whether
the supplements might prevent various forms of cancer.
This
study is best known for showing that smokers who took beta
carotene, which the body converts to vitamin A, actually
had higher rates of lung cancer.
Weinstein
looked at vitamin E and prostate cancer, and they looked
at how much E the men had in their blood before they ever
took a supplement. They looked at 100 men with prostate
cancer and 200 men who did not.
"We
found that the men who had higher serum (blood) levels of
vitamin E had a lower chance of getting prostate cancer,"
Weinstein told a news conference monitored by telephone.
NOT
ALL E'S ARE EQUAL
Then
they looked at the two main forms of vitamin E -- alpha
tocopherol and gamma tocopherol.
Men
with the highest natural levels of alpha tocopherol were
53 percent less likely to later develop prostate cancer.
Men with the highest levels of gamma tocopherol, which only
represents about 20 percent of the vitamin E in blood --
had a 39 percent lower chance.
Taking
supplements further reduced prostate cancer rates.
"Nuts
and seeds, whole grain products, vegetable oils, salad dressings,
margarine, beans, peas and other vegetables are good dietary
sources of vitamin E," Weinstein said.
In
a similar study, Dr. Xifeng Wu of the University of Texas
M.D. Anderson Cancer Center, John Radcliffe of Texas Woman's
University in Houston and colleagues studied 468 bladder
cancer patients and 534 cancer-free volunteers.
They
asked their 1,000 volunteers what they ate, and estimated
how much alpha-tocopherol and how much gamma tocopherol
they got in their everyday diets and from supplements if
they took them.
Those
with the highest intake of alpha tocopherol from food had
a 42 percent reduced risk of bladder cancer, and those who
had a vitamin E-rich diet and took supplements too had a
44 percent lower risk.
But
when broken down into types, they found gamma tocopherol
offered no protection against bladder cancer.
"It
would not be reckless to encourage people to try and meet
the dietary allowance of vitamin E, which is about 50 milligrams
a day," Radcliffe told the news conference. Current
average U.S. intake of E is only 8 mg a day.
One
of the best sources, said Radcliffe, a dietician, is a handful
of sunflower seeds. Almonds, spinach, mustard greens and
green and red peppers are also good sources of alpha tocopherol.
Many
E supplements, he said, contain both active and inactive
forms of E and may not be the best source. Plus, he said,
sunflower seeds are high in selenium, another key nutrient,
while greens are loaded with desirable nutrients.
http://www.chinadaily.net/english/doc
/2004-03/29/content_318811.htm
