The Potential Health Risks of High-Dose Vitamin E Supplement Use

by Health Canada

(Page 2 of 2)

Recently published studies have suggested that vitamin E supplements not only fail to prevent heart disease and cancer, but may actually harm people who take high doses over a long term. However, these studies are limited by the fact that they involved:

• people 55 years or older who already had heart disease or diabetes
• people with cancer or who previously had cancer
• people who may be at higher risk of developing these diseases.

One study found that patients with heart disease or diabetes who took 400 IU of vitamin E daily for an average of seven years were at a significantly increased risk of heart failure compared to patients who were not taking vitamin E supplements. This study concluded that high-dose vitamin E supplements (400 IU or greater) should not be taken by patients with heart disease or diabetes.

In another study, daily doses of 400 IU of vitamin E were given to patients receiving radiation therapy for cancers of the head and neck. The theory was that the antioxidant treatment might reduce the incidence of additional cancers of the same type among these patients. However, it was found that those who received vitamin E supplements were significantly more likely to develop other similar cancers during the supplementation period than those receiving a placebo.

All these studies have limitations. It is difficult to interpret how the results might apply to healthy people taking high doses of vitamin E. Although there are justifiable concerns over certain at-risk groups of consumers, more research is needed, especially focusing on the long-term use of high-dose vitamin E supplements.

Minimizing Your Risk

You should tell your doctor about all the medications and natural health products you use, including drugs, minerals, herbal products and high doses of vitamins, especially if you take a high-dose vitamin E supplement on a daily basis.

As well, you should take the following steps:

Use products that are authorised by Health Canada. Look for the 8-digit Drug Identification Number (DIN) or a Natural Product Number (NPN) on the label.

Follow all directions and warnings given on product labels.

If you have cancer or previously had cancer, or are 55 years of age or older and have been diagnosed with heart disease or diabetes, talk to your doctor before taking high-dose vitamin E supplements. This also applies to people being cared for who have these diseases.

If you suspect that you have had an adverse reaction to any product containing vitamin E, or any other health product, talk to your doctor or pharmacist.

Health Canada's Role

As a result of the recently published studies suggesting that high-dose vitamin E supplements may pose a health risk to certain groups of consumers, Health Canada is conducting an in-depth review of the scientific literature on the benefits and risks of high-doses of vitamin E. Should this review show that the potential risks outweigh the benefits, appropriate measures will be taken to maintain the health and safety of Canadians.

In the meantime, the Natural Health Products Directorate of Health Canada is drafting guidelines on vitamin E to ensure that manufacturers provide appropriate information on product labels. Such information would include recommended dosages, the length of time products should be taken, and information on potential risk.

About the Author

www.hc-sc.gc.ca
Health Canada is the Federal department responsible for helping Canadians maintain and improve their health, while respecting individual choices and circumstances.