Vitamin E – Tocopherol (Alpha, Beta, Gamma, Delta)
Tocopherols are a group of four chemical compounds discovered in 1922 by anatomist and embryologist Herbert McLean Evans. Evans was conducting feeding experiments on rats using vitamins B and C. During these experiments, Evans concluded that despite the rats being feed every known nutrient, they were still infertile.
Upon feeding them wheat germ, the rats were able to become pregnant. After years of experiments and studies attempting to isolate the unknown compound in wheat germ that allowed the rats to become fertile, Evans found the formula C29H50O2 and concluded that it reacted like an alcohol, making it part of a hydroxyl group. Evans named the compound after the Greek words “tokos” (birth) and “pherein” (to bear or carry) meaning, “to bear young”, adding the –ol to indicate the alcohol property of the compound. The structure of Tocopherols was later determined in 1938, over twenty years after the initial experiments.
Tocopherols are a lipid-soluble (fat-soluble) antioxidant that, when combined with corresponding tocotrienols, make up the common dietary supplement Vitamin E. However, almost all Tocopherols and tocotrienols have Vitamin E activity and properties, and can be correctly referred to as Vitamin E on their own. The four forms of Tocopherols are alpha, beta, gamma and delta.
Tocopherol is the form of vitamin E most easily absorbed by the human body, and found in the largest quantities in human blood serum. It is believed to be responsible for protecting cell membranes and reducing the risk of cardiovascular problems. It is the most found tocopherol in vitamin E supplements and in European diets.
Beta-tocopherol has lower vitamin E activity than the other three tocopherols and amounts found in human blood serum are lower than with alpha, gamma and delta tocopherols. While technically providing the same benefits of the other three tocopherols, it is not as easily absorbed by the human body and therefore is used only in small amounts in vitamin E supplements.
Tocopherol is second only to alpha-tocopherol in its vitamin E activity, and is the most common tocopherol found in the American diet. While it is higher in concentration than alpha-tocopherol in food sources, the liver removes it from human blood serum, causing it to be found in lesser amounts in the human body than alpha-tocopherol. Because of this, it is not an effective lipid antioxidant.
Tocopherol has a lower concentration in food sources than alpha-tocopherol or gamma-tocopherol, yet is more easily absorbed by the human body than gamma-tocopherol. Therefore, it is primarily used with alpha-tocopherol in vitamin E supplements, and it is believed that when delta tocopherol is combined with other tocopherols in a vitamin E supplement, the supplement is more easily absorbed by the human body.
Sources and Dosage
Doctors recommend that a 25-year-old male ingest 15 milligrams a day of vitamin E. Due to the fact that high amounts of vitamin E can act as an anticoagulant (preventing the clotting of blood), it is recommended that vitamin E intake not exceed 1,000 milligrams per day. Two American surveys in 1991 and 1994 indicated that most Americans do not consume the recommended amount of vitamin E, though a study by the Institute of Medicine in 2000 suggested that the surveys could be flawed because added fat during cooking is often under-reported. They believe that most Americans actually do receive the recommended amount of vitamin E from their normal diets, though caution those who consume low-fat diets to take a vitamin E supplement due to the lack of vegetable oils, a main source of vitamin E.
Besides vegetable oils, vitamin E is also found in high concentrations in nuts, seeds and whole grains. However, most Americans receive the bulk of their vitamin E from breakfast cereal and tomato sauce. Vitamin E is found in these sources, listed from highest to lowest: Wheat germ oil, sunflower oil, almond oil, sunflower seeds, almonds, hazelnuts, walnut oil, peanut oil, olive oil, poppy seed oil, peanuts, pollard, maize, poppy seeds, asparagus, oats, chestnuts, coconuts, tomatoes, walnuts, carrots and goat’s milk. While wheat germ oil contains 215.4 milligrams of vitamin E per 100 grams, goat’s milk only has .1 milligrams of vitamin E per 100 grams.
Synthetic Types & Supplements
Synthetic vitamin E is also added to packaged foods, especially cereals. Most fortified breakfast cereals can contain upwards of 24 milligrams of vitamin E per serving, which is well above the recommended intake of 15 milligrams per day.
For those consuming a low fat diet, vitamin E supplements are recommended. Natural supplements usually derive vitamin E from soybean oil, while synthetic supplements usually use straight alpha-tocopherols or a combination of alpha-tocopherols and one or two of the other tocopherols. Natural vitamin E supplements, while often more expensive, are recommended over synthetics as they are absorbed by the human body in larger quantities and more efficiently than synthetic vitamin E. Some supplements contain both natural and synthetic tocopherols, and are usually priced between the all natural and all synthetic versions of vitamin E.
Medical Usage and Health Benefits
The proper intake of vitamin E can help prevent and theoretically treat a host of common health concerns.
Alzheimer’s disease, a progressive form of dementia, is believed to be partially caused by oxidative stress. Studies suggest that high intake of vitamin E can prevent cell membranes from oxidizing, and therefore can be used as both a preventative measure and treatment for Alzheimer’s disease. However, studies are mixed as to whether vitamin E actually helps, with some trials indicating it does and others that it does not. Nonetheless, vitamin E has not been found to speed up the progression or onset of this disease.
Antioxidants such as vitamin E have been proven to help prevent the effect of free radicals on the human body, which are known to contribute to the development of chronic diseases such as cancer. Studies indicate that vitamin E may block carcinogens, a known cancer causing substance, from accumulating in the body, thereby preventing the development of certain cancers.
Vitamin E is also known to boost immune function, protecting those already with cancer from additional threats to their already weakened immune system. Most studies suggest that vitamin E primarily protects against prostate cancer and breast cancer, though it has not been shown to decrease the risk of breast cancer in postmenopausal women. On the contrary, recent studies have indicated that high intake of vitamin E by smokers can actually increase the risk of lung cancer by seven percent for each 100 IU of vitamin E taken daily.
Protect Your Eyes
Vitamin E has been found to protect the human eye from a host of diseases. When combined with other antioxidants, has been found to slow the onset and progression of age-related macular degeneration (AMD). AMD is an eye disease that usually develops after the age of 60 and the leading cause of vision problems and blindness among the elderly. However, vitamin E by itself has not been found to have any effect on the development of AMD.
Observational studies have indicated that regular use of vitamin E supplements in those that already consume the recommended amount of vitamin E in their diets reduces the risk of developing cataracts. In 2007, a study found that when vitamin E supplementation was added to other treatments for glaucoma, a disease damaging the optic nerve of the eye, it helped protect the spread of glaucomatous damage to the retina. Those treated with additional vitamin E showed significantly less vision impairment than those who were not.
In 2005, a study was published suggesting that vitamin E could help prevent the onset of Parkinson’s disease, a degeneration of the central nervous system that progressively impairs motor skills and speech. People who consumed foods high in vitamin E were found to have a lower risk of developing this devastating disease, though consuming these foods after the onset of Parkinson’s disease has not been shown to have any effect on the progression of the disease. In addition, use of supplemental vitamin E had no effect on either the onset of the disease or the progression.
Preventing Heart Disease
Vitamin E is widely believed to prevent or delay coronary heart disease, though this has only been found in small studies and disputed in larger studies. Vitamin E has been shown to reduce LDL-cholesterol (also known as “bad” cholesterol) and the formation of blood clots. LDL-cholesterol increases the risk of blockages in coronary arteries, which leads to atherosclerosis and heart attacks. Observational studies have indicated that those with a higher than usual intake of vitamin E were thirty to forty percent less likely to develop heart disease.
Despite this, clinical trials do not show the same outcome, though research is ongoing. Some studies indicate alpha-tocopherol only vitamin E supplements actually increase the risk of heart failure. When alpha-tocopherol was combined with gamma-tocopherol, this was not the case. The most promising use of vitamin E in regards to heart problems was found by the American Heart Association in 2007, when they stated that women taking regular doses of a vitamin E supplement were 21% less likely to suffer a blood clot than those who were not, though continuation of blood thinners was recommended for treatment.
Tocopherols are often used as a preservative in foods to prevent oils from going rancid, especially in dry pet food. A mix of all four tocopherols (alpha, beta, gamma and delta) has been found to be most effective for this application. Vitamin E is also widely used in cosmetics and as an additive in packaged foods. It is believed to be good for the skin, and is found in most moisturizers and foundations. Its predominance in these products, while possibly beneficial, is primarily because vitamin E is inexpensive. While marketing often preaches the benefits of vitamin E when applied topically, the research behind this claim is shady at best. Recent studies have indicated that 90% of study participants noticed no improvements in their appearance when vitamin E was added to a product and a third of these actually developed rashes from synthetic versions of vitamin E.
While vitamin E, when consumed according to guidelines, can be beneficial to one’s overall health, it can also increase morbidity rates when taken in excess. As with all things regarding one’s health, it is best to discuss vitamin E supplementation with one’s doctor.