A new U.S. study indicates taking vitamin E won't reduce a woman's risk of heart failure, the latest research to debunk the long-held claim the supplement helps prevent medical problems in aging.
However, the study, published in Tuesday's American Heart Association journal Circulation: Heart Failure, did observe one heart-related benefit of vitamin E use that the researchers say needs further investigation.
The study says it is the first to determine whether vitamin E — a group of fat-soluble anti-oxidants said to protect against cell damage — influences the risk of heart failure in a "primary prevention population."
"The cumulative evidence to date does not support the use of vitamin E supplementation to reduce the risk of cardiovascular diseases," concludes the study by Boston researchers from Massachusetts General Hospital, Brigham and Women's Hospital and Harvard Medical School.
Facts about heart failure in Canada:
- On the increase as a result of successes in treating heart attacks and other cardiac conditions.
- People with damaged hearts are more susceptible to heart failure.
- It's estimated 500,000 Canadians are living with heart failure and 50,000 new patients are diagnosed each year.
- Forty to 50 per cent of people with congestive heart failure die within five years of diagnosis.
Source: Heart and Stroke Foundation
While anti-oxidant therapy has been identified as promising in helping reduce the risk of heart failure, long-term supplement use has been linked to a higher chance of heart failure and hospitalization in certain groups, for instance, for people with vascular disease or diabetes.
Use of the supplement — which commonly comes in gel-like capsules — has been controversial on other fronts for a number of years.
In 2006, a Health Canada report warned that while E found naturally in foods such as seeds, nuts, green leafy vegetables and certain vegetable oils is safe and needed for good health, high-dose supplements may not be. Other medical bodies have also cautioned people against taking high doses of E in the belief they may prevent disease.
A U.S. study released in October 2011, for instance, concluded men taking 400 international units (IU) of vitamin E may have an increased risk of prostate cancer.
Heart failure rates rising
The Boston researchers say they focused on the vitamin's potential cardiovascular benefits because heart failure is a leading cause of death in North America, and a costly public health burden. Six million Americans and 500,000 Canadians are living with heart failure — a chronic, progressive condition in which the heart muscle is unable to pump enough blood to meet the body's needs for blood and oxygen.
The researchers focused on 39,815 women age 45 and older from the U.S. Women's Health Study (a separate randomized trial involving the use of low-dose Aspirin and vitamin E to study the prevention of cardiovascular disease and cancer).
The subjects in the vitamin E-heart failure study were considered healthy when the study began in 1993. They were either on 600 IU of vitamin E or a placebo every other day. During the 10 years they were tracked, 220 heart failure cases were reported.
But the study concludes vitamin E neither increased nor decreased the risk of heart failure among the women.
However, the researchers observed a 41 per cent decrease in the risk of developing a type of heart failure in which the heart retains its normal pumping function, a "sub-finding [that]
is only an observation and topic for future research," Dr. Claudia Chae, the study's lead researcher in the cardiology division at Massachusetts General Hospital, says in a release.
The researchers conclude that vitamin E shouldn't be used to reduce heart failure risk, and instead urged sticking with tried-and-true prevention methods: controlling blood pressure and preventing heart disease.