Vitamin E -3

Vitamin E and heart disease:
Preliminary research has led to a belief that vitamin E may help prevent or delay coronary heart disease.
Researchers have reported that oxidative changes to LDL-cholesterol (sometimes called "bad" cholesterol) promote blockages "atherosclerosis" in coronary arteries that may lead to heart attacks.
Vitamin E may help prevent or delay coronary heart disease by limiting the oxidation of LDL-cholesterol.
Vitamin E also may help prevent the formation of blood clots, which could lead to a heart attack.

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).
A 1994 review of 5,133 Finnish men and women aged 30-69 years also suggested that increased dietary intake of vitamin E was associated with decreased mortality (death) from heart disease.
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.
Even though these observations are promising, randomized clinical trials raise questions about the efficacy of vitamin E supplements in the prevention of heart disease.

The Heart Outcomes Prevention Evaluation (HOPE) Study followed almost 10,000 patients for 4.5 years who were at high risk for heart attack or stroke:
In this intervention study the subjects who received 265 mg (400 IU) of vitamin E daily did not experience significantly fewer cardiovascular events or hospitalizations for heart failure or chest pain when compared to those who received a placebo (sugar pill). The researchers suggested that it is unlikely that the vitamin E supplement provided any protection against cardiovascular disease in the HOPE study. This study is continuing, with the goal of determining whether a longer duration of intervention with vitamin E supplements will provide any protection against cardiovascular disease.

In a study sponsored by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health:
Postmenopausal women with heart disease who took supplements providing 400 IU vitamin E and 500 mg vitamin C twice a day, either alone or in combination with hormones, did not have fewer heart attacks or deaths. There was also no change in progression of their coronary disease.

The Women's Angiographic Vitamin and Estrogen (WAVE) trial:
Studied 423 Postmenopausal women at seven clinical centers in the U.S. and Canada. In postmenopausal women with coronary disease enrolled in this trial, neither hormone replacement therapy nor antioxidant vitamin supplements provided cardiovascular benefit.
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.
Results of the Women's Health Study, the Women's Antioxidant and Cardiovascular Study and the SUVIMAX study, all of which are investigating the effects of vitamin supplements on the progression of coronary heart disease, are due in 2005 and will provide additional information on the association between vitamin E supplements and cardiovascular disease.

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.
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.
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.

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. So it is recommended that, when selecting a vitamin E supplement, choosing the one which contains other tocopherols and tocotrienols, not just alpha-tocopherol.
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.

The tocotrienols:
  • It is a one of the 8 members of the vitamin E family, 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.
  • 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.
  • Tocotrienolshave been shown to inhibit the growth of estrogen receptor positive breast cancer cells by as much as 50% in culture.
It therefore appears that the individual tocopherol and tocotrienols have different biological activities as they relate to their effects on health, and it is recommended that, when choosing a vitamin E product, the selection one which also contains other tocopherol and tocotrienols, not just alpha-tocopherol.
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, it is better to take them with a meal or with fatty acid capsules like fish oil (EPA-DHA) e.g. "Omega 3 plus".
Prostate cancer: Some evidence associates higher intake of vitamin E with a decreased incidence of prostate cancer although the evidence is not overwhelming.
The American Cancer society recently released the results of a long-term study that evaluated the effect of regular use of vitamin C and vitamin E supplements on bladder cancer mortality in almost 1,000,000 adults in the U.S. The study, conducted between the years 1982 to 1998, found that subjects who regularly consumed a vitamin E supplement for longer than 10 years had a reduced risk of death from bladder cancer. No benefit was seen from vitamin C supplements.

Vitamin E and cataracts:
Cataracts are abnormal growths in the lens of the eye. These growths cloud vision. Cataracts also increase the risk of disability and blindness in aging adults.
Antioxidants are being studied to determine whether they can help prevent or delay cataract growth.
Observational studies have found that lens clarity, which is used to diagnose cataracts, was better in regular users of vitamin E supplements and in persons with higher blood levels of vitamin E. 
A study of middle-aged male smokers, however, did not demonstrate any effect from vitamin E supplements on the incidence of cataract formation.
The effects of smoking, a major risk factor for developing cataracts, may have overridden any potential benefit from the vitamin E, but the conflicting results also indicate a need for further studies before researchers can confidently recommend extra vitamin E for the prevention of cataracts.

Vitamin E and lipid peroxidation:
Lipid peroxidation refers to the oxidative degradation of lipids. It is the process whereby free radicals "steal" electrons from the lipids in cell membranes, resulting in cell damage. This process proceeds by a free radical chain reaction mechanism. It most often affects polyunsaturated fatty acids, because they contain multiple double bonds in between which lie methylene -CH2- groups that are especially reactive hydrogen. As with any radical reaction the reaction consists of three major steps: initiation, propagation and termination.
Currently, the biological activity of Vitamin E is to prevent lipid peroxidation. Since alpha-tocopherol is the most active tocopherol against peroxyl radicals (LOO.) and delta-tocopherol is the least active (alpha>beta=gamma>delta). The anti-oxidant activity of Vitamin E is based on the ease with which the hydrogen on the hydroxyl group of the chroman ring can be donated to neutralize a free radical (creating a more stabile tocopheroxyl radical).

Vitamin E and the immune system:
Vitamin E is particularly protective against exercise-induced free radicals. For a healthy non-smoking person seeking to boost immune system function, reduce cancer risk and reduce membrane lipid peroxidation damage during exercise (or protect mitochondria in general) through Vitamin E supplementation, a mixture of alpha-tocopherol and gamma-tocopherol supplements would be prudent- along with supplementation with Co-Enzyme Q10 and Vitamin K.