Scientists are studying vitamin E to understand how it
affects health. Here are several examples of what this
research has shown.
Heart disease
Many population studies have found that people with higher
levels of vitamin E in their bodies have a lower risk of
heart disease. Researchers have investigated whether taking
vitamin E supplements might help prevent heart disease, but
the results have not shown any benefit.
One of the largest studies, the Heart Outcomes Prevention
Evaluation (HOPE) trial, found that taking 400 IU of vitamin
E (d-alpha-tocopherol) daily did not lower the number of
heart attacks, strokes, or deaths from heart disease among
men and women who already had heart disease, or those who
were at high risk for developing it.
Among otherwise healthy people who were at low risk for
heart disease, two large trials also found no protection
from vitamin E. In one, the Physicians' Health Study II,
vitamin E was associated with a higher risk of stroke. This
study generated a lot of controversy and is still being
debated today.
One large clinical study suggested that vitamin E from
foods, not supplements, may reduce the risk of death from
stroke in postmenopausal women.
Cancer
Population studies (observing large
groups of people over time) suggest that eating foods high
in vitamin E and other antioxidants may help prevent cancer.
Other studies show that people with cancer often have lower
levels of vitamin E. Researchers wondered if antioxidants
like vitamin E can help prevent cancer. But evidence about
vitamin E supplements has not backed this up.
Several large studies show that women who take vitamin E
supplements do not have a lower risk of developing breast
cancer. One large study found that men who took 400 IU of
vitamin E every other day for 8 years did not have a lower
risk of overall cancer than those who took placebo.
Vitamin E also does not seem to protect against colorectal
cancer in women or people with diabetes. There is some
evidence that taking vitamin E, along with vitamin A and
vitamin C, or as part of a multivitamin, may offer some
protection to people who had colorectal adenomas. Colorectal
adenomas are considered to be a precursor to developing
colon cancer.
Vitamin E does not seem to protect against lung cancer or
pancreatic cancer. In fact, one study of more than 77,000
men showed a small but significant increase in lung cancer
associated with taking vitamin E supplements.
The evidence about vitamin E and prostate cancer is mixed.
Some population studies suggest that people who take more
vitamin E have a lower risk of prostate cancer. Other
studies suggest the opposite: One study found that men who
took a multivitamin more than 7 times per week, along with a
separate vitamin E supplement, had a higher risk of prostate
cancer. Another study of 35,000 men found that those who
took a vitamin E supplement had a 17% increase in the risk
of developing prostate cancer than those who took placebo.
One study found that taking a combination of 30 mg vitamin E
(alpha-tocopherol), 120 mg vitamin C, 6 mg beta-carotene,
100 mcg selenium, and 20 mg zinc did not lower the overall
risk of prostate cancer, but it might reduce the risk in men
whose PSA levels were normal. High PSA levels can indicate
prostate cancer.
Another large study of 29,133 smokers found that those
taking 50 mg daily of vitamin E (dl-alpha-tocopherol, or
synthetic vitamin E) had a lower risk of prostate cancer and
deaths caused by prostate cancer.
Researchers note that taking antioxidant supplements may not
work as well as eating antioxidant foods. Many experts
believe getting antioxidants from foods may be the best way
to protect against cancer.
Also, there is only limited evidence that taking large doses
of vitamin E may help with cancer treatment. One study of
108 people taking the chemotherapy therapy drug cisplatin
found that taking a vitamin E supplement during, and as long
as 3 months after, treatment reduced nerve damage that can
happen when taking cisplatin. However, some doctors worry
that large doses of antioxidants from supplements could
interfere with chemotherapy medications. If you are
undergoing chemotherapy, talk to your doctor before taking
vitamin E or any supplement.
The most recent evidence seems to suggest that dietary
vitamin E and low-dose tocopherols are cancer preventive,
while high-dose supplementation with alpha tocopherol is
not. Research is ongoing. Consult a physician to determine
the role of vitamin E in specific cases.
Eye disorders
Vitamin E (400 IU) combined with other antioxidants,
including zinc (80 mg), beta-carotene (15mg), and vitamin C
(500 mg), seems to protect against developing age-related
macular degeneration (AMD). AMD is the leading cause of
legal blindness in people over 55 in the United States.
People with advanced AMD seemed to get the biggest benefit.
Researchers do not know whether this combination of
nutrients helps prevent AMD or helps people with less
advanced AMD.
Vitamins E and C may also help treat uveitis. Uveitis is
inflammation of the uvea, the middle layer of the eye
between the sclera (white outer coat of the eye) and the
retina. A clinical study of 130 people with uveitis found
that those who took these vitamins had clearer vision than
those who took placebo.
Mental function
Evidence is mixed as to whether vitamin E can help prevent
or treat Alzheimer disease. Some researchers believe that
antioxidants may help prevent Alzheimer disease. One study
found that people who had levels of all the forms of vitamin
E, not just d-alpha-tocopherol, the kind usually found in
supplements, were less likely to develop Alzheimer's. But
another study found that people who had early symptoms of
Alzheimer's and took vitamin E supplements went on to
develop the disease at the same rate as those who took
placebo.
In one study with positive results, 341 people with
Alzheimer disease took either 2,000 IU of vitamin E
(dl-alpha-tocopherol), the drug selegiline, or placebo.
Those who were given vitamin E took about 200 days longer
for the disease to progress to severe than those who took
placebo. However, selegiline worked even better.
Photodermatitis
This condition involves an allergic type reaction to the UV
rays of the sun. An 8-day clinical study comparing treatment
with vitamins C and E to placebo found that people who took
the vitamins became significantly less sensitive to the sun.
Another clinical study, lasting for 50 days, also showed a
protective effect of the vitamin C and E combination.
Menstrual Pain
A few studies have found that vitamin E may help relieve
menstrual pain or dysmenorrhea. In one study, women who took
500 IU of vitamin E for 2 days before and 3 days after their
periods started had less pain than those who took placebo.
A few studies also suggest that vitamin E supplements may
help reduce PMS symptoms, including anxiety, food cravings,
and depression.
Diabetes
People with diabetes tend to have low levels of
antioxidants, which has led some researchers to believe that
this might explain why they are at increased risk for
conditions such as heart disease.
Vitamin E supplements and other antioxidants may help reduce
the risk of heart disease and other complications in people
with diabetes. Research shows that antioxidants may help
control blood sugar levels and lower cholesterol levels in
people with type 2 diabetes while protecting against the
complications of eye damage (retinopathy) and kidney damage
(nephropathy) in those with type 1 diabetes. One study found
that people with type 2 diabetes who took 400 IU of vitamin
E daily reduced their risk of heart attack and of dying from
heart disease.
However, not all studies have found that taking vitamin E
supplements helps people with diabetes. If you have
diabetes, ask your doctor whether a vitamin E supplement is
right for you.
Pre-eclampsia
Some studies suggest that taking vitamin E along with
vitamin C may help prevent pre-eclampsia in women who are at
high risk. Women with pre-eclampsia have high blood pressure
and too much protein in the urine. Pre-eclampsia is a common
cause of premature births. Not all studies agree, however.
Women should speak with their physicians before taking
vitamin E during pregnancy.
Tardive dyskinesia
Some small studies have suggest that vitamin E supplements
may help treat tardive dyskinesia, involuntary, repetitive
movements that are a side effect of taking certain
medications for a long time. However, not all studies have
found that vitamin E can help. The largest study found that
taking 1,600 IU of vitamin E daily for at least one year was
no better at reducing tardive dyskinesia symptoms than
placebo.
Rheumatoid arthritis
One study suggests that taking vitamin E, along with
standard medications for rheumatoid arthritis, may help
reduce pain, but not inflammation, better than standard
medications alone.