The Health Diva

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 breast 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 analysed 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 tocotrienols, 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.

Tocotrienols 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]

Prostate cancer: some evidence associates higher intake of vitamin E with a decreased incidence of prostate cancer [17], although the evidence is not overwhelming.