Cancer is a leading cause of death in many western cultures, second only to heart disease. A wide array of research bodies exist to provide solid evidence that this killer disease is largely promoted by poor lifestyle habits, especially diet. Medical researchers have long known that there is a definite connection between cancer and the fat soluble vitamin E. Some studies have concluded a positive relationship between the two, while others vilify vitamin E as a cancer progenitor.
Researchers at the Center for Cancer Prevention Research at Rutgers University have published the result of a study in the journal Cancer Prevention Research that demonstrates that vitamin E from dietary sources has a profound effect on cancer development and progression. The scientists have found that two forms of vitamin E, gamma and delta-tocopherols found in soybean, canola and corn oils as well as nuts do prevent colon, lung, breast and prostate cancers.
Researchers know that in the past, studies have shown an increased risk of cancer and decrease in bone density with vitamin E from supplements. Unfortunately, those studies either used a synthetic form of the vitamin known as dl-alpha- tocopherol or they did not specify the form of vitamin E used. Vitamin E exists in a variety of forms called tocotrienols and tocopherols which occur in natural balance in many nuts, seeds and their cold-pressed oils.
Dr. Yang commented “When animals are exposed to cancer-causing substances, the group that was fed these tocopherols in their diet had fewer and smaller tumors… when cancer cells were injected into mice these tocopherols also slowed down the development of tumors.” Researchers noted that studies conducted using the synthetic mono-isomer form of vitamin E commonly used in inexpensive multi-vitamins (dl-alpha- tocopherol ) not only did not prevent prostate cancer, but its use significantly increased the risk of this disease among healthy men.
This study demonstrates the importance of consuming vitamin E from natural food sources such as nuts, seeds, and their oils to benefit from the full spectrum of tocotrienols and tocopherols, specifically the gamma and delta isomers. Dr. Yang concluded “For people who think that they need to take vitamin E supplements, taking a mixture of vitamin E that resembles what is in our diet would be the most prudent supplement to take.” One to two servings of nuts, seeds, or oil extracts daily (or a natural food-based supplement) are sufficient to provide the full benefits of all vitamin E isomers shown to significantly lower cancer risk.
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Yes, there is some evidence suggesting a protective effect of vitamin E against prostate, bladder, and colorectal cancer, but more research is needed. Most clinical studies show that vitamin E supplements do not have any overall health benefit or any beneficial effect on heart disease or cancer in general, and may even lead to increased risk of heart failure. Available scientific evidence does not support claims that vitamin E significantly affects the growth of cancers that have already formed.
A balanced diet normally gives the body the amount vitamin E it needs, especially a diet low in fat and high in green leafy vegetables and fiber from grains and cereals. The recommended daily allowance (RDA) of vitamin E for adults is 15 milligrams per day from food, with 19 milligrams per day recommended for women who are breast-feeding. (Vitamin E is often measured as IU (International Units); one milligram equals 1.5 IU.) This recommendation was revised by the National Academy of Science (NAS) in April 2000. It also set the upper limit of intake from supplements at 1,000 milligrams (1,500 IU) per day.
Vitamin E supplements are taken as capsules, with a typical dose being 400 IU per day.
Vitamin E has also been studied in clinical trials of people who have had one cancer in order to see if it could keep the cancer from coming back (cancer recurrence) or prevent a second, new cancer. Clinical trials of people with head and neck cancer found it did not reduce the risk of recurrence or the risk of a second cancer.
Many researchers and clinicians believe that taking high doses of antioxidant vitamins may change how well radiation therapy and some chemotherapy drugs work, but they often disagree as to whether the changes are beneficial or harmful. Some researchers and doctors think antioxidants like vitamin E might reduce side effects or even improve effectiveness of radiation or chemotherapy. Others are concerned that antioxidants will reduce effectiveness of these treatments. Very few studies have yet been done in humans to test these theories, and there is no clear consensus yet. Most oncologists advise their patients to avoid antioxidant vitamin and mineral supplements during treatment, but some surveys suggest this advice is often ignored by patients. Further studies are needed to resolve this important question.