Vitamin E - Why Vitamin E is important to our Body

Vitamin E is a fat-soluble vitamin that occurs in various forms, alpha-tocopherol being the only one used by the human body. Its main role is to act as an antioxidant, scavenging loose electron - known as "free radicals" - that can damage cells. It also strengthens immune function and prevents the formation of blood clots in the arteries of the heart.

Antioxidant vitamins, including vitamin E, came to prominence in the 1980s when scientists realized that free radical damage was involved in the early stages of artery-clogging atherosclerosis and may also contribute to cancer, vision loss, and a number of other chronic diseases. Vitamin E has the ability to protect cells from free radical damage and reduce free radical production in certain situations. However, conflicting study results have somewhat dampened the promising effects of high-dose vitamin E for chronic disease prevention.

Why Vitamin E is important to our Body?

A- Heart Problems

For a while, it looked like taking vitamin E supplements was an easy way to prevent cardiovascular disease. The most recent review of evidence from clinical trials by the U.S. Preventive Services Task Force found no conclusive benefit of vitamin E supplements in preventing cardiovascular disease and therefore recommended against their use. Although some large observational studies and clinical trials have shown heart-protective benefits of these supplements, especially in relatively healthy people, most randomized clinical trials have shown no benefit, either in healthy people or in people at risk for or suffering from heart disease.

Advantages:

Observational studies: The Nurses' Health Study and the Health Professionals Follow-Up Study found that the risk of heart disease decreased by 20-40% in people who took vitamin E supplements (usually containing 400 IU or more) for at least two years.

Randomized controlled trials: in the Women's Health Study, which followed nearly 40,000 healthy women for 10 years, daily use of vitamin E supplements containing 600 IU did not significantly reduce the risk of so-called "major cardiac events" (heart attack, stroke, or cardiovascular death). But the results were also encouraging: when these serious cardiac events were analyzed separately, vitamin E intake was associated with a 24% lower risk of cardiovascular death. Among women aged 65 years and older, vitamin E supplementation reduced the risk of serious cardiac events by 26%. A later analysis found that women taking vitamin E supplements also had a lower risk of developing serious blood clots in the legs and lungs, with women at the highest risk for such blood clots receiving the greatest benefit.

Disadvantages:

Randomized controlled trials in people who were at high risk for heart disease or already had heart disease at baseline. In the GISSI Prevention Trial, results were mixed but largely showed no preventive effect after more than three years of treatment with vitamin E in 11,000 heart attack survivors. Results from the Heart Outcomes Prevention Evaluation (HOPE) trial also showed no benefit from four years of vitamin E supplementation in more than 9,500 men and women already diagnosed with or at high risk for heart disease. In fact, when the HOPE study was extended for an additional four years, researchers found that study participants taking vitamin E had a higher risk of heart failure.

Based on such studies, the American Heart Association concluded that "the scientific data do not justify the use of antioxidant vitamin supplements (such as vitamin E) to reduce CVD risk." It is possible that the use of medications such as aspirin, beta-blockers, and ACE inhibitors may mask a modest effect of vitamin E in people who already have heart disease or who are at high risk for heart disease, and that vitamin E may be of benefit in healthier people.

Randomized controlled trials in people without heart disease at baseline. The SU.VI.MAX randomized controlled trial found that seven years of low-dose vitamin E supplementation (as part of a daily antioxidant pill) reduced cancer risk and risk of death from any cause in men but showed no such beneficial effects in women; the supplements did not offer protection against heart disease in either men or women. Discouraging results also came from the Physicians' Health Study II, an eight-year randomized controlled trial that enrolled nearly 15,000 middle-aged men, most of whom had no heart disease at baseline. The researchers found that a daily intake of 400 IU of vitamin E, alone or with vitamin C, did not provide protection against heart attacks, strokes, or cardiovascular death.

Recent evidence leads to the theory that vitamin E supplements may be beneficial only for certain subgroups of the general population. For example, a study of high-dose vitamin E in Israel showed a significant reduction in heart disease in people with type 2 diabetes who shared a genetic predisposition to greater oxidative stress.

B- Cancer

Overall, observational studies have not shown that vitamin E in foods or supplements provides significant protection against cancer in general or against specific cancers. The most recent review by the U.S. Preventive Services Task Force of the evidence from clinical trials on the effectiveness of vitamin E in cancer also found no benefit from these supplements in terms of reduced incidence of cancer or death from cancer. Observational studies and clinical trials are conflicting: some suggest that vitamin E supplements may reduce the risk of advanced prostate cancer in smokers, while one large randomized trial suggests that vitamin E increases the risk of prostate cancer.

Prostate Cancer

The researchers had hoped that the Selenium and Vitamin E Cancer Prevention Trial would provide more definitive answers on the subject of vitamin E and prostate cancer. The 18,000 men who participated in the SELECT trial were to take one of four pill regimens - vitamin E plus selenium, vitamin E plus selenium placebo, selenium plus vitamin E placebo, or a double placebo - and be followed for 7 to 12 years. However, the researchers stopped the study halfway through in 2008 when early analyses showed that vitamin E offered no benefit in preventing cancer or prostate cancer. [28] Although the study ended, the researchers continued to follow the participating men. In 2011, they reported a 17% higher risk of prostate cancer in the men taking vitamin E; there was no significantly increased risk of prostate cancer in the men taking vitamin E and selenium.

Although these results may sound worrisome, two other large studies on vitamin E and prostate cancer reached quite different conclusions: The Randomized Alpha-Tocopherol Beta-Carotene Study, for example, followed nearly 30,000 Finnish male smokers for an average of six years. It found that men who took vitamin E daily had a 32% lower risk of developing prostate cancer - and a 41% lower risk of dying from prostate cancer - than men who received a placebo. The protective effect of vitamin E was strongest in men whose cancer was advanced enough to be detected during a clinical examination. The large and long-term Physicians' Health Study II found that taking vitamin E neither increased nor decreased the risk of prostate cancer or any other cancer.

Why are the selected results on vitamin E and prostate cancer so different from those of previous studies? Previous studies of vitamin E supplements and prostate cancer found the greatest benefit in men who were smokers and in whom the cancer was more advanced. However, in the Select study, fewer than 10% of the men were smokers, and most had early-stage cancer detected by blood tests for prostate-specific antigen (PSA). Many low-grade early-stage prostate cancers detected by PSA testing would not develop into advanced cancers. There is also evidence that different processes occur in early-stage prostate cancer than in late-stage prostate cancer. In a large study of a drug used to prevent prostate cancer, it was found that the effect was the opposite in early and advanced prostate cancer.

It should be remembered that prostate cancer usually develops slowly, and any study of prostate cancer prevention must follow men over a long period of time. Because the SELECT study was stopped early, it is not possible to determine whether vitamin E would have helped protect against prostate cancer in some men if they had continued in the study for a longer period. There were very few cases of advanced prostate cancer in the SELECT trial, further limiting the interpretation of the results.

Source of Food:

Vitamin E is found in plant-based oils, nuts, seeds, fruits, and vegetables.

1. Wheat germ oil
2. Sunflower, safflower, and soybean oil
3. Sunflower seeds
4. Almonds
5. Peanuts, peanut butter
6. Beet greens, collard greens, spinach
7. Pumpkin
8. Red bell pepper
9. Asparagus
10. Mango
11. Avocado

Symptoms of Weakness and Toxic Effect

Because vitamin E is found in a variety of foods and supplements, deficiency is rare in the United States. People who suffer from digestive disorders or who do not absorb fat properly (e.g., pancreatitis, cystic fibrosis, celiac disease) may develop a vitamin E deficiency. Common signs of deficiency include the following:

1. Retinopathy (damage to the retina of the eye that can affect vision).
2. Peripheral neuropathy (damage to peripheral nerves, usually in the hands or feet, that causes weakness or pain)
3. Ataxia (loss of control over body movements)
4. Weakened immune function

Toxic Effect:

There is no evidence of toxic effects from vitamin E, which occurs naturally in foods. Most adults who consume more than the RDA value of 22 IU daily use multivitamins or separate vitamin E supplements containing between 400 and 1000 IU daily. There are no reports of harmful side effects from taking supplements in healthy people. However, there is a risk of excessive bleeding, especially at doses greater than 1000 mg per day or with the concomitant use of blood-thinning medications such as warfarin. For this reason, an upper limit for vitamin E of 1000 mg daily (1465 IU) of any form of tocopherol supplementation has been established for adults 19 years of age and older.

Important Information:

Due to occasional reports of negative health effects from vitamin E supplements, scientists have debated whether these supplements could be harmful and even increase the risk of death.

Researchers have attempted to answer this question by combining the results of several studies. In one such analysis, the authors pooled and reanalyzed data from 19 clinical trials of vitamin E, including the GISSI and HOPE studies; they found a higher mortality rate in the studies in which patients took more than 400 IU of supplements per day. Although this meta-analysis made headlines when it was published, the conclusions that can be drawn are limited. Some of the results are based on very small studies. In some of these studies, vitamin E was combined with high doses of beta-carotene, which itself has been associated with increased mortality.  In addition, many of the studies using high-dose vitamin E included people with advanced heart disease or Alzheimer's disease. Other meta-analyses reached different conclusions. So it's not clear whether these results would hold for healthy people. For example, the Physicians' Health Study II found no difference in mortality rates between study participants who took vitamin E and those who received a placebo.