The term vitamin E describes a family of 8 antioxidants, 4 tocopherols and 4 tocotrienols. alpha-tocopherol (a-tocopherol) is the only form of vitamin E that is actively maintained in the human body and is therefore, the form of vitamin E found in the largest quantities in the blood and tissue.
Why do we need vitamin E?
Vitamin E, a fat-soluble vitamin, protects vitamin A and essential fatty acids from oxidation in the body cells and prevents breakdown of body tissues.
Do we get enough vitamin E?
According to recent surveys of the U.S. Department of Agriculture (USDA), the intake of vitamin E by women 19 to 50 years of age averaged less than 90% of the Recommended Daily Allowance (RDA). Men of the same age had intakes close to 100% of the RDA. We need to remind ourselves that the RDA is an absolute minimum requirement, below which your body is actually in deficiency.
Vitamin E can be lost from foods during preparation, cooking, or storage.
Beyond taking enough vitamin E to prevent an actual deficiency, is there any scientific evidence which shows that taking vitamin E in higher levels can promote good health and prevent and treat disease? Let's examine this question.
Vitamin E and heart disease
Support for the role of vitamin E in heart disease prevention has come from observational studies, particularly 2 cohort studies which were published in 1993. In the 1st study, the Nurses' Health Study, the researchers concluded that among 83,234 middle-aged women who participated in the study, there was a 40% reduced risk of coronary artery disease for those who took vitamin E supplements compared to those who did not (New England Journal of Medicine 1993;328: 1444-9). The 2nd study, the Health Professionals Follow-up Study, involved over 39,000 males and showed evidence of a significant association between a high intake of vitamin E from supplements and a lower risk of heart disease (New England Journal of Medicine 1993; 328:1450-1456).
Researchers are fairly certain that oxidative modification of LDL-cholesterol ("bad" cholesterol) promotes blockages in coronary arteries which may lead to atherosclerosis and heart attacks. Vitamin E may help prevent or delay coronary heart disease by limiting the oxidation of LDL-cholesterol. A 1994 review of 5,133 Finnish men and women aged 30 - 69 suggested that increased dietary intake of vitamin E was associated with decreased mortality from heart disease (1).
vitamin e and ldl cholesterol
The results of at least 5 large observational studies suggest that increased vitamin E consumption is associated with a decreased risk of myocardial infarction (heart attack) in both women and men. Each study was a prospective study that measured vitamin E consumption in presumably healthy people and followed them for several years to determine how many of them were diagnosed with, or died as a result of heart disease.
2 other large studies (1,2) found a significant reduction in the risk of heart disease only in those men and women who consumed alpha-tocopherol supplements of at least 100 IU daily, with the greatest benefit observed at an intake of 800 IU daily (3).
While 100 IU or more of supplemental vitamin E per day has been shown to reduce the risk of heart attacks in healthy individuals, those with pre-existing coronary artery disease often take 800 to 1200 IU/day based on the pioneering work of the Shute brothers in the mid 1940s.
Vitamin E and cancer
The evidence is not as clear-cut when it comes to cancer and vitamin E. Many types of cancer are believed to result from oxidative damage to DNA caused by free radicals. Antioxidants - such as vitamin E - help protect against the damaging effects of free radicals, which may contribute to the development of chronic diseases such as cancer. Vitamin E also may block the formation of nitrosamines, which are carcinogens formed in the stomach from nitrites consumed in the diet. Vitamin E may also protect against the development of cancers by enhancing immune function (6). However, human trials and surveys which tried to associate vitamin E with incidence of cancer have generally been inconclusive.
The Nurses Health Study, which we referred to earlier, studied 83,234 women at baseline and sought to assess the incidence of breast cancer during a 14-year follow-up. The study showed that pre-menopausal women with a family history of breast cancer who consumed the highest quantity of vitamin E enjoyed a 43% reduction in breast cancer incidence compared to only a 16% risk reduction for women without a family history of breast cancer.(8)
Based on this study, vitamin E appears to protect against genetic-predisposed breast cancer better than environmentally-induced breast cancer.
However other studies which have reviewed the effects of standard vitamin E products (alpha-tocopherol acetate) taken by themselves have failed to decisively show a protective benefit for cancer.(7,9) It is possible that other forms of vitamin E found in food (such as gamma tocopherol and tocotrienols) may be responsible for providing the protective effect against breast cancer shown in some surveys which evaluated total vitamin E intake. This is why I recommend that, when selecting a vitamin E supplement, you choose one which contains other tocopherols and tocotrienols, not just alpha-tocopherol.
In 2002, a researcher at Wake Forest University School of Medicine compiled and analyzed the large volume of published data about vitamin E and breast cancer and her comprehensive work was published in the Journal of Nutritional Biochemistry.(4)
Taken together, the results of the studies presented indicate that certain vitamin E compounds found in food confer a significant protective effect, but that commercial alpha-tocopherol acetate supplements fail to reduce the incidence of breast cancer for most women. The data indicates that some other vitamin E compounds in food may account for the dramatic reductions in breast cancer incidence when dietary intake levels of vitamin E are measured.
Most studies have indicated that the form of vitamin E used in most commercial preparations (alpha-tocopherol acetate) has not been shown to protect against breast cancer.
It is the , one of the 8 members of the vitamin E family, however, which have demonstrated the most significant potential to not only reduce breast cancer incidence, but also to inhibit the propagation of existing breast cancer cells.
have been shown to inhibit the growth of estrogen receptor positive breast cancer cells by as much as 50% in culture.(10,12)
The objective of any cancer therapy is to induce the cancer cells to differentiate in a way which promotes programmed cell death (apoptosis). Several studies indicate that tocotrienols induce breast cancer cell apoptosis.[13,14]
It therefore appears that the individual tocopherols and tocotrienols have different biological activities as they relate to their effects on health, and it is my recommendation that, when choosing a vitamin E product, you select one which also contains other tocopherols and tocotrienols, not just alpha-tocopherol. I recommend the book " The Vitamin E Factor " for a better understanding of the importance of tocotrienols and the other tocopherols.
It is especially important to take the tocotrienols along with some form of oil or fat-containing food. When tocotrienols are taken on an empty stomach, absorption is reduced by an average of 50%.
So when taking tocopherol and/or tocotrienol vitamin E supplements, I would recommend that you take them with a meal or with fatty acid capsules like fish oil (EPA-DHA).
Prostate cancer: some evidence associates higher intake of vitamin E with a decreased incidence of prostate cancer (17), although the evidence is not overwhelming.
Vitamin E and the risk of Alzheimer's disease.
Some evidence on the role of vitamin E in reducing the risk of Alzheimer's was reported in 3 recent studies. The first study, conducted at the Rush Institute for Healthy Aging of the Rush-Presbyterian-St Luke's Medical Center found that an increased vitamin E intake from foods was associated with a decreased risk of developing Alzheimer's disease.
The second study, conducted in the Netherlands, showed that vitamin E from food, but not other antioxidants, may be associated with a decreased risk. The third study, which was conducted in Italy, evaluated a high dose of 2,000 IU and found a substantial protective effect. It appears that the effect of vitamin E from supplements is detectable only with high doses.
Vitamin E and cataracts
Cataracts are growths on the lens of the eye which cloud the vision. They increase the risk of blindness and disability in aging adults. Antioxidants are being studied to determine whether they can help delay or prevent cataract growth. Observational studies have found that lens clarity, which is used to diagnose cataracts, is better in regular users of vitamin E supplements and in people with higher blood levels of vitamin E (16).
Vitamin E from food or supplements?
Our bodies do not manufacture vitamin E. We have to get our vitamin E either from our food or from supplements. Scientific studies also tell us that we need to take much higher levels of vitamin E than the Recommended Daily Allowance (RDA) to get its full benefits. Because vitamin E is fat-soluble, it is generally found in fat-rich foods. Can we get enough vitamin E from our food without ingesting thousands of fat calories? Which foods should we choose?
You can get vitamin E from 4 main groups:
* Vegetable oils. Corn, canola, sunflower, sesame, cottonseed, peanut, rice bran, and palm oils.
* Nuts - almonds, walnuts, peanuts, pistachios and hazelnuts.
* Oil seeds, legumes and grains. Corn, lentils, wheat, rice, northern beans, chickpeas, and oats.
* Extracted from the germ of wheat, Wheat germ oil has been used since the '20s as a vitamin E supplement. It offers a good combination of tocopherols plus tocotrienols.
But many scientists believe it is difficult for an individual to consume more than 15 mg/day of alpha-tocopherol from food alone, without also increasing fat intake above recommended levels.
If, like me, you believe that you need much more vitamin E than the RDA to fend off diseases, delay the onset of aging and even possibly slow down the progress of diseases like Alzheimer's, then it is extremely difficult to get these amounts from food alone.
Food is a great way to get natural vitamin E, the whole family of compounds. You can easily meet the RDA if you include nuts, legumes and grains in your diet and use modest amounts of vegetable oils.
If you don't want to take vitamin E supplements then consider wheat germ and . These are great sources of natural vitamin E. Because they are rich in vitamin E you can raise your intake without taking in too much fat.
If on the other hand, you wish to take vitamin E supplements, then the question becomes: how do I pick the right vitamin E product?
8 different compounds, 4 tocopherols and 4 tocotrienols make up the vitamin E family. Our food contains all eight compounds. Not so for most vitamin E supplements. Most contain only alpha-tocopherol. The best vitamin E products contain all 8 members of the vitamin E family - tocopherols plus tocotrienols - in their NATURAL form.
Why is the natural form of vitamin E better than the synthetic form?
In one word, the difference is: availability. Natural vitamin E has roughly twice the availability of synthetic vitamin E.
Most vitamins are produced as synthetic. Most of the vitamins used to make nutritional supplements (tablets, capsules, etc.) are synthetic. Same thing for the vitamins used to fortify our cereals, milk, and other foods. Is there a problem with that? For most vitamins NO. The synthetic molecules behave and look exactly the same as the ones found in our food.
Not so for alpha-tocopherol. There is a difference in the molecule, in its potency and in the way it behaves in the body.
Here is the difference: The d-alpha-tocopherol in our food, the natural form, is a single entity, in other words all the molecules are identical. By contrast, the synthetic dl-alpha-tocopherol is a mixture of 8 different molecular entities, known in the chemical jargon as "stereoisomers". Of these 8, only 1 is identical to the natural form. The other 7 do not exist in nature.
Synthetic dl-alpha-tocopherol is not harmful. But its value to your body is only 1/2 of the natural.
Read the label - it's the only way to tell if you are getting natural or synthetic. Natural will say "d-alpha-tocopherol", synthetic will say "dl-alpha-tocopherol".
What is the health risk of too much vitamin E?
The health risk of too much vitamin E is low (18). A recent review of the safety of vitamin E in the elderly concluded that taking vitamin E supplements for up to 4 months at doses of 530 mg or 800 IU (35 times the current RDA) had no negative side-effect on general health, body weight, levels of body proteins, lipid levels, liver or kidney function, thyroid hormones, amount or kinds of blood cells, and bleeding time (19).
It should however be noted that ingestion of total vitamin E products in excess of 1200 IU daily may interfere with absorption and metabolism of vitamins A and K. But one can get benefits with much lower levels of vitamin E.
The Institute of Medicine has set an upper tolerable intake level for vitamin E at 1,000 mg (1,500 IU)/day for any form of supplementary alpha-tocopherol because the nutrient can act as an anti-coagulant and increase the risk of bleeding problems. Upper tolerable intake levels "represent the maximum intake of a nutrient that is likely to pose no risk of adverse health effects in almost all individuals in the general population" (5).
One important caveat is for people who are on "blood thinners". Individuals on anti-coagulant therapy or individuals who are vitamin K deficient should not take alpha-tocopherol supplements without close medical supervision because of the increased risk of hemorrhage.
I spend a lot of time researching the internet for the best prices on supplements, and in my opinion the best prices for high-quality vitamin E can be found . I also like Puritan Pride's special on vitamin E.
Vitamin E requires the presence of fats and bile in the gut to be absorbed. The degree to which vitamin E is absorbed by the body is dependent on the total absorption of dietary fat.