Questions and Answers about Vitamin E

[Guest guest]

Questions and Answers about Vitamin E

http://crnusa.org/vitaminEissafe.html

 

Like many people, you may have questions about some of the recent

stories that have been in the news about vitamin E. Here is some useful

advice to help you better understand the safety and benefits of vitamin E.

 

Q. I’ve seen some confusing news in the paper about vitamin E. Although

I’ve taken vitamin E daily for almost 10 years, I now wonder about its

safety. Is this vitamin safe?

 

A. Yes. Vitamin E is very safe. Like all vitamins, it is by definition

essential for life. Your body needs it to protect against damage caused

by free radicals, oxidized substances that can be associated with heart

disease and cancer. In addition, many studies have shown that vitamin E

boosts the immune system, reduces the risk of developing various vision

disorders including cataracts or macular degeneration, and improves

brain functio–enhancing short term memory while reducing the risk of

developing Alzheimer’s disease.

 

Q. An article I read suggested that vitamin E may be harmful. What is

that all about?

 

A. Some researchers from Johns Hopkins University conducted a

meta-analysis (see related fact sheet) of 19 studies conducted with

patient groups, many of whom were elderly, and taking multiple

prescription medications because they already had chronic diseases

including Alzheimer’s disease, Parkinson’s disease, kidney failure or

heart disease. The researchers interpreted their data to suggest that

high doses of vitamin E may be associated with a slight increased risk

of death. Many of the nation’s leading antioxidant experts reviewed the

study and said they were not convinced of an increased risk and in fact

noted that vitamin E is safe within a wide range of intakes.

 

Q. Can I get all the needed vitamin E through diet?

 

A. Most people do not get the Recommended Dietary Allowance of vitamin E

(15 mg) from their diet alone. That’s why so many of us need to take a

supplement to ensure adequate intake. You can get more vitamin E into

your diet by consuming such foods as nuts, green leafy vegetables and

fortified cereals. You can also get vitamin E from a multivitamin or a

single vitamin E supplement.

 

Q. Is it safe to take more vitamin E than what I can get in a multivitamin?

 

A. Yes, and for many people high doses of vitamin E is beneficial. The

Institute of Medicine, a scientific advisory body, has set an Upper

Level (a dose at which there is no known harm) for vitamin E at 1000 mg

(1000 IU or synthetic vitamin E, or 1500 IU natural vitamin E).

 

Q. What is the common dose of vitamin E?

 

A. The most commonly marketed dose of single-nutrient vitamin E in the

U.S. is 400 IU.

 

Q. What is the link between vitamin E and the protection of my eyesight?

 

A. A number of studies spotlight the association between vitamin E and

reduced risk of cataracts (a major cause of blindness throughout the

world) and macular degeneration (the number one cause of vision

impairment in the United States). In one study of people taking a

multivitamin or a supplement of C or E for a decade, results showed a

60% lower incidence of cataracts among the group taking a supplement.

Other studies of people taking vitamins E, C and zinc demonstrated they

were better protected from advanced macular degeneration than those

individuals who didn’t take them.

 

Q. Does vitamin E offer protection against developing Alzheimer’s disease?

 

A. There is evidence to suggest that medications or vitamins (such as

vitamin E) that increase the levels of catecholamines, certain chemicals

in the brain, can protect the neurons from damage that could otherwise

lead to Alzheimer’s disease. In addition, according to a wide range of

other studies, antioxidants like vitamin E can improve brain function,

short-term memory, problem-solving and general reasoning skills.

 

Q. Does vitamin E help protect against cancer?

 

A. Studies have linked reduced rates of cancers of the prostate, breast,

and bladder with higher intakes of vitamin E. It is believed that

antioxidants such as vitamin E reduce the risk because they help protect

cell membranes from free radicals—a byproduct of cellular metabolism.

They bind free radicals before they can do damage to the cell.

 

Q. Does vitamin E help protect against heart disease?

 

A. A large body of experimental study and some clinical research studies

have indicated a link between intake of the antioxidant vitamin E and a

reduced risk of heart disease. In addition, several ongoing trials are

being conducted between vitamin E and the risk of heart disease.

 

Q. Is it important to continue studying the effects of vitamin E?

 

A. Absolutely. Many studies underway around the world will add to our

knowledge over the coming years, so that we can optimize the level and

formulation of vitamin E for various

age groups and for people with inherited risk factors for a wide range

of diseases.

 

Vitamin E meta-analysis in Annals of Internal Medicine:

What’s wrong with this picture?

 

What is a meta-analysis?

 

A meta-analysis is not a clinical trial. It is a statistical technique

for combining the results of many existing studies in order to clarify

possible effects. When studies are done with a few hundred or even a few

thousand people, it is often difficult to determine whether differences

between the treatment group and the placebo group are " real " or just

accidents due to chance. Combining studies provides more people for

analysis and thus increases statistical power. While a meta-analysis is

an important scientific tool, it also has limitations.

 

What is all-cause mortality?

 

Studies are generally designed to look at some particular outcome, like

whether vitamin E reduced the risk of having a heart attack. However, in

studies involving sick people and lasting for several years, there will

be other outcomes, such as death. A certain number of people in longterm

studies are going to die, and all-cause mortality is the number of

people who died from any cause—whether or not the cause has anything to

do with the purpose of the study. All-cause mortality includes people

who died of heart disease or infectious disease or cancer or getting hit

by a bus. The number of people who die in the treatment group and in the

control group will rarely be exactly equal. Statistical analysis tells

us whether differences in total mortality between the treatment group

and the control group are significant or just the result of chance.

 

What did this study find, overall?

 

This study analyzed 19 clinical trials in which vitamin E was given,

involving a total of almost 140,000 people. Eighteen of the 19 trials

individually found no statistically significant increase in total

mortality in the vitamin E group. Even when all of the 19 trials were

combined, there was no significant increase in total mortality. The

study authors say, " The average death risk across trials in the control

groups was 1022 per 10,000 persons. Overall, vitamin E supplementation

did not affect all-cause mortality. "

 

What did the study find, relating to high and low doses of vitamin E?

 

When the trials were divided according to the dose of vitamin E, the

researchers found that low doses of vitamin E slightly decreased total

mortality while high doses of vitamin E (400 IU or more) slightly

increased total mortality. The researchers said this was a statistically

significant effect, but others have criticized whether it has practical

meaning. Most of the high-dose studies were done in people who already

had various diseases and the authors say that these findings may not be

generalizable to healthy adults. However, they go on to generalize,

saying that people should avoid high-dose vitamin E and indeed high

doses of any vitamin—a conclusion much more sweeping than is justified

by their analysis.

 

Were there other findings?

 

The researchers also did a dose-response analysis of the clinical

trials, which found a statistically significant (but very small)

increase in mortality only when the vitamin E dose was greater than 900

IU. This is contrary to the finding in their main meta-analysis that

doses over 400 IU might confer increased risk.

 

What were the 19 studies used in this meta-analysis?

 

The studies chosen for the meta-analysis all lasted more than one year

and reported at least 10 deaths from all causes. Studies in which no

deaths occurred were not included in the analysis. The studies were

originally published in the decade from 1993 to 2004. Some of the

studies involved over 20,000 people, and some involved only a few

hundred people. Doses used in the studies ranged from 16.5 IU to 2000 IU

and were given for periods from one to 8 years. In some studies the

vitamin E was given as part of a multivitamin or some other mixture of

nutrients, and in some studies vitamin E was given as a single nutrient.

The studies were conducted in various parts of the world—Europe, Asia,

the Middle East, Australia, Canada, and the U.S. Vitamin E was given in

these studies for many different purposes, including reducing the risk

of heart disease, cancer, and macular degeneration and delaying the

progression of cataracts, kidney disease, Alzheimer’s disease and

Parkinson’s disease. Some of the studies found a benefit of vitamin E

for these purposes.

 

Do any of the studies show a benefit from vitamin E?

 

Yes. Many of the 19 clinical studies used in this meta-analysis actually

showed a health benefit from vitamin E. For example, one study in

England showed that vitamin E at levels of 400 and 800 IU reduced the

risk of heart attack by 75% in men who already had symptoms of heart

disease. A study in patients with kidney failure found a reduced risk of

heart attacks and of death from heart disease in people who were given

800 IU of vitamin E. Another of the studies found that vitamin E (400

IU) in combination with some other nutrients reduced the risk of

age-related macular degeneration, the leading cause of blindness in

elderly people. And one study showed that a very high dose of vitamin E

(2000 IU) delayed the progression of Alzheimer’s disease.

 

Do epidemiologic studies show a benefit from vitamin E?

 

Yes. Numerous epidemiologic studies have shown a benefit from vitamin E.

In an epidemiologic study, researchers simply observe whether people who

use certain products or adopt certain habits on their own have more or

less disease than people who do not. A Harvard study of more than 80,000

nurses found a 41% reduction in the risk of heart disease in nurses who

had used vitamin E supplements for at least 2 years. A Harvard study of

almost 40,000 male health professionals (mostly dentists) found that men

who took vitamin E supplements for more than 2 years had a 37% reduced

risk of heart disease. A study conducted by the National Institute of

Aging in 11,000 elderly people found that those who used supplements of

vitamins C and E had a 53 percent reduction in mortality from heart

disease and a 42 percent reduction in all-cause mortality, compared to

non-users.

 

Are more studies being done using high-dose vitamin E?

 

Yes. A number of new clinical trials are now under way, and researchers

are attempting to reassure the people enrolled in these trials that

vitamin E is safe and that the research should continue. They include

the Women’s Health Study involving over 40,000 female health

professionals, the Physicians’ Health Study involving thousands of U.S.

doctors, and the Women’s Antioxidant Cardiovascular Disease Study. Also,

the National Cancer Institute is sponsoring the Selenium and Vitamin E

Chemoprevention Trial (SELECT) to evaluate the effects of these two

nutrients in protecting against prostate cancer in more than 30,000 men.

 

Was it reasonable to select 400 IU as the cutoff between low-dose and

high-dose vitamin E?

 

No. Four hundred IU was an arbitrary number. It is not evident how the

researchers chose to define 400 IU and not some other value as the

" high-dose " mark, except that it is the most commonly marketed dose in

the U.S. Two important studies including the GISSI trial in Italy used

330 IU of vitamin E—not much lower than 400 IU. Including those in the

high-dose group would have been reasonable, and the positive effects of

the GISSI trial would have offset some of the studies showing a trend

toward increased mortality. Below that dose, there is only one study at

200 IU, also showing a slightly beneficial effect on total mortality.

The truly " low-dose " studies are the five that used only 60 IU or less

of vitamin E. In short, it appears that 400 IU rather than 200 or 300 IU

may have been arbitrarily selected as the high-dose cutoff in order to

bolster a finding of risk.

 

How much vitamin E is safe?

 

The Institute of Medicine, a scientific advisory body, has concluded

that vitamin E is safe for chronic use in the general population at

levels up to 1000 mg (1000 IU synthetic vitamin E, 1500 IU natural

vitamin E). The Recommended Dietary Allowance for vitamin E is 15 mg

(15-22.5 IU, depending on the chemical form), and only a small fraction

of the population gets this much from diet alone. Most multivitamins

contain 15 to 60 IU of vitamin E.

 

What should people think about this meta-analysis?

 

This meta-analysis does not change what is known about vitamin E safety.

It used no new research but instead combined 19 studies in order to

create statistical significance for a finding of a slight increase in

all-cause mortality in studies that used 400 IU or more of vitamin E,

but overall the studies showed no such increase and a dose-response

analysis showed a significant increase only at levels above 900 IU. The

authors have exaggerated the practical significance of their findings to

attract attention and scare the public. As a result, numerous

participants in ongoing clinical trials on high-dose vitamin E sponsored

by the National Cancer Institute have been needlessly frightened, and

the future of the studies may be endangered. Consumers who are already

using vitamin E should continue to use it with confidence, and people

who are not currently using at least a multivitamin containing vitamin E

should consider doing so, since the overwhelming majority of the

population fails to get the recommended amount of vitamin E from diet

alone.

[Guest guest]

Regarding the vitamin E article:

What's best, mixed tocopherol or d-alpha tocopherol?

I have been taking the d-alpha because the brands I've

seen never tell you what the percentages of the different

types if E are in the " mixed tocopherols " .

Any thoughts or feekback? d.

[Guest guest]

you want to find one that has gamma as the dominant of the mixed

tocoopherols. I work for a doctor who specialized in alternative medicine

and he found that the NOW brand of gamma-e is the best option.

 

>Dave R Hermanson <tumblweed4

>

>

> Re: Questions and Answers about

>Vitamin E

>Fri, 3 Dec 2004 06:30:56 -0600

>

>

>

>

>Regarding the vitamin E article:

>What's best, mixed tocopherol or d-alpha tocopherol?

>I have been taking the d-alpha because the brands I've

>seen never tell you what the percentages of the different

>types if E are in the " mixed tocopherols " .

>Any thoughts or feekback? d.

>

>

>