Vitamin E got itself a reputation as a "sex vitamin" early on. When it was being tested on laboratory animals, it gave every sign of deserving that reputation. When male animals were deprived of vitamin E, their testicles shrank. In pregnant female animals with vitamin E deficiency, the fetuses were reabsorbed into the uterus, preventing the animals from bearing young. Giving the animals even a single drop of vitamin E–rich wheat germ oil restored their fertility. In fact, vitamin E got its scientific name, tocopherol, from this particular ability. It means "to bring forth offspring."
Today, most vitamin E research focuses on much broader roles, such as preventing heart disease and cancer. And since most people don’t get enough vitamin E from foods to protect themselves from these diseases, it wasn’t long before favorable reports on vitamin E began to affect sales of the supplements. Soon, sales of vitamin E were catching up with those of vitamin C, the biggest-selling single supplement nutrient in the United States.
A Heart Helper
In the case of heart disease, two studies from Harvard University involving a total of about 135,000 health professionals found that those who took daily supplements of vitamin E were one-fourth to one-third less likely to develop heart disease than those who didn’t take supplements. They took at least 100 international units (IU) over a period of at least two years.
A study done in England, called the Cambridge Heart Antioxidant Study, showed that people with heart disease who took at least 400 IU of vitamin E had about one-quarter the risk of having nonfatal heart attacks compared with people who took look-alike pills (placebos) that didn’t contain any vitamin E.
Researchers in another study found that among male smokers who took 50 to 75 IU a day of vitamin E, the incidence of prostate cancer was reduced by about one-third. There were 41 percent fewer deaths from prostate cancer among the men who took vitamin E as opposed to those who didn’t.
Many other studies point to areas in which vitamin E looks promising. In Boston, for instance, Tufts University researchers discovered that 200 IU a day of supplemental vitamin E could reverse age-related declines in immune function. Researchers at Columbia University in New York City found that people with Alzheimer’s disease who took 2,000 IU a day were able to delay certain problems associated with the disease. Those who took the supplement were able to go longer (by seven months) before they lost their ability to groom or feed themselves or had to make a switch from their own homes to nursing homes.
SUPPLEMENTSNAPSHOT
| Vitamin E Supplement forms: D-alpha-tocopherol, d-alpha tocopheryl acetate, d-alpha tocopheryl succinate, and dl-alpha tocopheryl acetate. May help: Heart disease, angina, cancer, multiple sclerosis, diabetes, Alzheimer’s disease, cataracts, emphysema, high cholesterol, intermittent claudication, infertility, impotence, genital herpes, bedsores, leg cramps, muscle soreness, phlebitis, menopausal discomforts, HIV, osteoarthritis, and chronic inflammatory diseases such as lupus and rheumatoid arthritis. Daily Value: 30 international units. Special instructions: For doses higher than the Daily Value, take in divided doses with meals that contain some fat. Take a natural form (d-alpha tocopherol or d-alpha tocopheryl acetate or succinate). Who’s at risk for deficiency: People who can’t absorb fat properly and those with Crohn’s disease or cystic fibrosis. Good food sources: Almonds, spinach, turnip greens, mustard greens, kohlrabi, kale, dandelion greens, margarine, peanut oil, safflower oil, soybean oil, sunflower oil and seeds, wheat germ, and wheat-germ oil. Cautions and possible side effects: Use only with medical supervision if you are taking anticoagulants (blood thinners), ginkgo, or fish-oil supplements; if you take aspirin regularly to help prevent heart disease; if you have high blood pressure, heart disease, or cancer; if you smoke; if you have had a stroke; or if you are at high risk for stroke. Although vita min E is commonly sold in doses of 400 IU, one small study showed a possible risk of stroke in doses over 200 IU. |
For treatment of rheumatoid arthritis, vitamin E also has shown promise. European researchers have found that people with rheumatoid arthritis who take 800 IU a day of vitamin E report less pain than those who go without it.
Playground Supervisor
Vitamin E apparently has only one major role in the body, but that one is a whopper. "It functions as our bodies’ major fat-soluble antioxidant," says Maret Traber, Ph.D., principal investigator at the Linus Pauling Institute and associate professor of nutrition at Oregon State University in Corvallis. Vitamin E is found throughout our bodies in the tissues that contain fat, including the protective membranes surrounding cells and their nuclei, which contain the genetic material.
This all-important vitamin is also found in the fatty sheaths that wrap around and insulate nerves and in molecules called lipoproteins, which circulate in our blood. "In these places, vitamin E helps to neutralize molecular particles called free radicals that are produced as a normal part of reactions that involve oxygen," Dr. Traber says.
These reactions, called oxidation-reduction reactions, go on all the time. Problems occur, though, when a chemical reaction generates a free radical. "A free radical is a molecule that has an unpaired electron, making it unstable," Dr. Traber says. Because the imbalance makes it hungry for an electron, it steals one from some other molecule.
Stopping A Chain Reaction
Unfortunately, that means that another molecule is short an electron, so it becomes a free radical that in turn strives to pluck an electron from some other unlucky molecule nearby. The effect is a chain reaction of free radical damage, kind of like a game of tag that’s gotten out of control.
This innocent game leads to trouble. Cell membranes are damaged, sometimes beyond repair. Cell contents leak out, and the cell dies. Or, if the damage occurs in the membranes inside a cell, the cell’s genetic material is harmed.
If the damage occurs in the membrane of the cell’s power plant, the mitochondria, trouble multiplies like a breakout fight at a hockey game. Free radicals normally generated inside the mitochondria leak out into the cell. Cellular unrest spreads like wildfire.
Vitamin E can stop all this by donating one of its own electrons to a free radical. When that happens, there’s no chain reaction. Vitamin E stops the outbreak of electron-grabbing dead in its tracks. You could think of it as a playground supervisor for that rowdy game of tag.
High-Speed Chase
Vitamin E moves with uncanny speed throughout the fluid cell membrane. Because it moves so quickly, it can help protect about 1,000 of the molecules that make up the membrane, Dr. Traber says. Once it neutralizes a free radical, the vitamin E twists within the membrane so that its free radical part is exposed to the watery solution surrounding the cell. There, it meets up with any vitamin C that’s available, and vitamin C is an award-winning ally in this process. It regenerates vitamin E by giving up one of its own electrons, allowing vitamin E to go right back to work.
Many diseases, and even aging, seem to be associated with free radical oxidative damage, Dr. Traber says. Cancer, for instance, may be started by free radical damage to a cell’s genetic material. Heart disease may begin when free radicals oxidize LDL cholesterol, the artery-clogging kind of free-floating fat that doctors monitor most closely. In effect, the free radicals turn this fat rancid. In so doing, they initiate what is thought to be an early step in heart disease.
Also, it seems that inflammation anywhere in the body—joints, nerves, or connective tissues—may well involve out-of-control free radical damage, Dr. Traber says. That’s why vitamin E and other antioxidants, such as vita min C, are being studied for their effects on such a variety of conditions.
Supplements Are Essential
The amounts of vitamin E that studies suggest provide protection from heart disease or enhance immunity can’t be gotten from even an exemplary diet. The Daily Value for vitamin E is 30 IU, but estimates of an optimal dose really start at around 100 IU. You’d have to eat 58 cups of boiled spinach, 6 cups of peanuts, 1½ cups of corn oil, or three tablespoons of wheat germ oil to get close to that amount.
If you are watching your weight and reducing the amount of fat in your diet, you are even less likely to get close to the DV for vitamin E. In one study of people who had cut their fat intake below 30 percent of calories, daily vitamin E intake dropped from 14.5 to 9.5 IU.
Even the DV, however, is only a measure of what it takes to prevent a deficiency, while most of us, and most doctors, are interested in how much we might need to significantly improve health. There’s a huge gap between the DV and what researchers call the optimal value. And when it comes to discussing optimal value, there’s even more divergence of opinions and recommended amounts.
While some researchers recommend from 100 to 400 IU a day, a number of clinicians recommend even higher amounts for people age 45 and older or for those with chronic diseases. One study, from researchers at the University of Texas Southwestern Medical Center in Dallas, found that the minimum dose of vitamin E required to significantly reduce LDL oxidation was 400 IU a day. Doses up to 1,200 IU—which is 40 times the DV—provided additional benefits. Taking 200 IU a day did not significantly reduce LDL oxidation, they found. Given this wide range of results, Dr. Traber and other experts are involved in ongoing discussions about new guidelines for recommending vitamin E.
Is E for You?
Certainly, it’s worth discussing with your doctor whether you should take vitamin E supplements, and of course, you’ll want to ask about risks. One concern is that large doses of vitamin E might elevate the risk of bleeding problems and lead to hemorrhagic stroke, a fairly uncommon type. Unlike other strokes, it’s caused not by a blood clot but by a bleeding or broken blood vessel in the brain.
The same study that saw a reduction in the risk of prostate cancer in men taking 50 to 75 IU of vitamin E also saw an increase in the number of hemorrhagic strokes in the vitamin E takers. The percentage of men in the study who actually had strokes, though, remained fairly small.
"This is a finding that poses additional questions and requires further study," says Demetrius Albanes, M.D., a senior investigator in the cancer prevention studies branch of the National Cancer Institute.
The link with hemorrhagic stroke is directly related to the way vitamin E works. One reason that vitamin E helps to reduce heart attack risk is that it interferes with little particles in the blood called platelets, which play a role in blood clotting. Platelets can clump together or stick to artery walls when they shouldn’t, which can cause a clot that closes off an artery. Vita min E helps to prevent that, but it could also prevent the platelets from sticking and clumping when they need to.
Until there are answers about vitamin E’s real effects on the risk of bleeding problems, and until additional research supports vitamin E’s beneficial effects on cancer and cardiovascular disease, Dr. Albanes suggests caution when you consider taking more than the Daily Value. Before giving you the go-ahead for large doses of vitamin E, your doctor can do a test that checks your bleeding time. With that test in hand, you’re better able to discuss the benefits versus possible risks.
Choosing the Right Form
As for what form of vitamin E to take, several studies support the use of vitamin E in its natural form, d-alpha tocopherol, over its synthetic form, dl-alpha tocopheryl acetate. The natural form is twice as active, so manufacturers make up for that by putting more of the synthetic form into capsules. But natural vitamin E is also retained twice as long in the body as synthetic vitamin E, which means that it can build up and stay at higher levels.
Natural vitamin E also contains more than just d-alpha tocopherol. It is typically combined with other forms, such as gamma tocopherol, that appear to offer added protection. Researchers at the University of California at Berkeley, for example, discovered that gamma tocopherol also has powerful antioxidant properties. These other tocopherols are not present in synthetic vitamin E, although they are found in foods rich in the vitamin.
Multivitamins usually contain vitamin E in one of its water-soluble forms, d-alpha tocopheryl acetate or d-alpha tocopheryl succinate. These forms are just as good as d-alpha tocopherol, Dr. Traber says.
Most multivitamins don’t offer enough vitamin E for optimal protection from chronic disease, however. If you want to take more than 100 IU of vitamin E a day, you need to take either an antioxidant formula or supplements that contain only vitamin E (usually d-alpha tocopherol), she says.
