Vitamin E supplementation shows no overall benefit for major cardiovascular events or cancer

July 05, 2005

In an article in the July 6 JAMA, I-Min Lee, M.B.B.S., Sc.D., of Brigham and Women's Hospital and Harvard Medical School, Boston, and colleagues analyzed data from the vitamin E component of the Women's Health Study, which tested whether vitamin E supplementation decreases the risk of cardiovascular disease and cancer among healthy women.

According to background information in the article, previous observational studies have indicated that vitamin E may be beneficial in lowering the risk for some cardiovascular diseases; and high antioxidant intake has been linked to reduced cancer rates. For small to moderate effects, however, the amount of uncontrolled and uncontrollable confounding inherent in observational studies can be as large as the postulated benefit, so randomized clinical trials represent the most reliable study design strategy. Randomized trials do not generally support benefits of vitamin E, but there are few trials of long duration among initially healthy persons. By 1997, despite a lack of randomized trials, 44 percent of U.S. cardiologists reported routine use of antioxidant supplements, primarily vitamin E, compared with 42 percent who routinely used aspirin for the primary prevention of CVD.

In this component of the Women's Health Study, 39,876 apparently healthy U.S. women aged at least 45 years were randomly assigned to receive 600 IU of natural-source vitamin E on alternate days or placebo, and were followed up for an average of 10.1 years.

The researchers found with the vitamin E group, there was no significant effect on major cardiovascular events, on the incidences of heart attack or stroke, as well as ischemic or hemorrhagic stroke. For cardiovascular death, there was a 24 percent reduction. There was no significant effect on the incidences of total cancer or breast, lung, or colon cancers. Cancer deaths also did not differ significantly between groups. There was no significant effect of vitamin E on total death.

"In conclusion, the WHS does not support recommending vitamin E supplementation for CVD or cancer prevention among healthy women. This large trial supports current guidelines stating that use of antioxidant vitamins is not justified for CVD risk reduction. ... The WHS findings should be viewed in the context of the available randomized evidence, as well as data that should be available over the next several years from ongoing trials, including the Physicians' Health Study, which will provide data on primary prevention in men. At present, in the primary prevention of CVD and cancer, therapeutic lifestyle changes including a healthy diet and control of major risk factors remain important clinical and public health strategies," the authors conclude.

(JAMA. 2005;294:56-65. Available pre-embargo to the media at www.jamamedia.org)

Editor's Note: For funding/support and financial disclosure information, please see the JAMA article.

Editorial: Vitamin E and Cardiovascular Health

In an accompanying editorial, Rita F. Redberg, M.D., M.Sc., of the University of California, San Francisco, discusses the study by Lee et al.

"Perhaps it is time to consider devoting some of the limited resources necessary to perform randomized controlled trials to other pressing, unanswered questions in the field of cardiovascular disease prevention in women. With the publication of the WHS vitamin E results, it is time to redirect attention to interventions that have been shown to or could provide significant benefit."

" ... vitamin E enters the category of therapies that were promising in epidemiologic and observational studies but failed to deliver in adequately powered randomized controlled trials. As in other studies, the 'healthy user' bias must be considered, i.e., the healthy lifestyle behaviors that characterize individuals who care enough about their health to take various supplements are actually responsible for the better health, but this is minimized with the rigorous trial design. It is estimated that almost 1 million preventable deaths per year are due to smoking, poor diet, and physical inactivity. Perhaps the most important outcome of the WHS reports will be greater recognition that it is time to concentrate on teaching nutrition, promoting regular physical activity, and strongly encouraging smoking cessation and particularly increasing outreach to women of racial and ethnic minorities," Dr. Redberg writes. "[These] are underused but proven prevention strategies for heart disease. Interestingly, these positive lifestyle changes are also associated with the prevention of cancer and Alzheimer disease."

(JAMA. 2005;294:107-109. Available pre-embargo to the media at www.jamamedia.org)
-end-


The JAMA Network Journals

Related Cancer Articles from Brightsurf:

New blood cancer treatment works by selectively interfering with cancer cell signalling
University of Alberta scientists have identified the mechanism of action behind a new type of precision cancer drug for blood cancers that is set for human trials, according to research published in Nature Communications.

UCI researchers uncover cancer cell vulnerabilities; may lead to better cancer therapies
A new University of California, Irvine-led study reveals a protein responsible for genetic changes resulting in a variety of cancers, may also be the key to more effective, targeted cancer therapy.

Breast cancer treatment costs highest among young women with metastic cancer
In a fight for their lives, young women, age 18-44, spend double the amount of older women to survive metastatic breast cancer, according to a large statewide study by the University of North Carolina at Chapel Hill.

Cancer mortality continues steady decline, driven by progress against lung cancer
The cancer death rate declined by 29% from 1991 to 2017, including a 2.2% drop from 2016 to 2017, the largest single-year drop in cancer mortality ever reported.

Stress in cervical cancer patients associated with higher risk of cancer-specific mortality
Psychological stress was associated with a higher risk of cancer-specific mortality in women diagnosed with cervical cancer.

Cancer-sniffing dogs 97% accurate in identifying lung cancer, according to study in JAOA
The next step will be to further fractionate the samples based on chemical and physical properties, presenting them back to the dogs until the specific biomarkers for each cancer are identified.

Moffitt Cancer Center researchers identify one way T cell function may fail in cancer
Moffitt Cancer Center researchers have discovered a mechanism by which one type of immune cell, CD8+ T cells, can become dysfunctional, impeding its ability to seek and kill cancer cells.

More cancer survivors, fewer cancer specialists point to challenge in meeting care needs
An aging population, a growing number of cancer survivors, and a projected shortage of cancer care providers will result in a challenge in delivering the care for cancer survivors in the United States if systemic changes are not made.

New cancer vaccine platform a potential tool for efficacious targeted cancer therapy
Researchers at the University of Helsinki have discovered a solution in the form of a cancer vaccine platform for improving the efficacy of oncolytic viruses used in cancer treatment.

American Cancer Society outlines blueprint for cancer control in the 21st century
The American Cancer Society is outlining its vision for cancer control in the decades ahead in a series of articles that forms the basis of a national cancer control plan.

Read More: Cancer News and Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.