Featured Research

from universities, journals, and other organizations

Use Of Some Antioxidant Supplements May Increase Mortality Risk

Date:
February 28, 2007
Source:
JAMA and Archives Journals
Summary:
Contradicting claims of disease prevention, an analysis of previous studies indicates that the antioxidant supplements beta carotene, vitamin A and vitamin E may increase the risk of death, according to a meta-analysis and review article in the Feb. 28 issue of JAMA.

Contradicting claims of disease prevention, an analysis of previous studies indicates that the antioxidant supplements beta carotene, vitamin A, and vitamin E may increase the risk of death, according to a meta-analysis and review article in the February 28 issue of JAMA.

Many people take antioxidant supplements, believing they improve their health and prevent diseases. Whether these supplements are beneficial or harmful is uncertain, according to background information in the article.

Goran Bjelakovic, M.D., Dr.Med.Sci., of the Center for Clinical Intervention Research, Copenhagen University Hospital, Copenhagen, Denmark, and colleagues conducted an analysis of previous studies to examine the effects of antioxidant supplements (beta carotene, vitamins A and E, vitamin C [ascorbic acid], and selenium) on all-cause death of adults included in primary and secondary prevention trials. Using electronic databases and bibliographies, the researchers identified and included 68 randomized trials with 232,606 participants in the review and meta-analysis. The authors also classified the trials according to the risk of bias based on the quality of the methods used in the study, and stratified trials as "low-bias risk" (high quality) or "high-bias risk" (low quality).

In an analysis that pooled all low-bias risk and high bias risk trials, there was no significant association between antioxidant use and mortality. In 47 low-bias trials involving 180,938 participants, the antioxidant supplements were associated with a 5 percent increased risk of mortality. Among low-bias trials, use of beta carotene, vitamin A, and vitamin E was associated with 7 percent, 16 percent and 4 percent, respectively, increased risk of mortality, whereas there was no increased mortality risk associated with vitamin C or selenium use.

"Our systematic review contains a number of findings. Beta carotene, vitamin A, and vitamin E given singly or combined with other antioxidant supplements significantly increase mortality. There is no evidence that vitamin C may increase longevity. We lack evidence to refute a potential negative effect of vitamin C on survival. Selenium tended to reduce mortality, but we need more research on this question," the authors write.

"Our findings contradict the findings of observational studies, claiming that antioxidants improve health. Considering that 10 percent to 20 percent of the adult population (80-160 million people) in North America and Europe may consume the assessed supplements, the public health consequences may be substantial. We are exposed to intense marketing with a contrary statement, which is also reflected by the high number of publications per included randomized trial found in the present review."

"There are several possible explanations for the negative effect of antioxidant supplements on mortality. Although oxidative stress has a hypothesized role in the pathogenesis of many chronic diseases, it may be the consequence of pathological conditions. By eliminating free radicals from our organism, we interfere with some essential defensive mechanisms . Antioxidant supplements are synthetic and not subjected to the same rigorous toxicity studies as other pharmaceutical agents. Better understanding of mechanisms and actions of antioxidants in relation to a potential disease is needed," the researchers conclude.


Story Source:

The above story is based on materials provided by JAMA and Archives Journals. Note: Materials may be edited for content and length.


Cite This Page:

JAMA and Archives Journals. "Use Of Some Antioxidant Supplements May Increase Mortality Risk." ScienceDaily. ScienceDaily, 28 February 2007. <www.sciencedaily.com/releases/2007/02/070227171026.htm>.
JAMA and Archives Journals. (2007, February 28). Use Of Some Antioxidant Supplements May Increase Mortality Risk. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2007/02/070227171026.htm
JAMA and Archives Journals. "Use Of Some Antioxidant Supplements May Increase Mortality Risk." ScienceDaily. www.sciencedaily.com/releases/2007/02/070227171026.htm (accessed September 17, 2014).

Share This



More Health & Medicine News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Artificial Sweetener Could Promote Diabetes

Artificial Sweetener Could Promote Diabetes

Newsy (Sep. 17, 2014) Doctors once thought artificial sweeteners lacked the health risks of sugar, but a new study says they can impact blood sugar levels the same way. Video provided by Newsy
Powered by NewsLook.com
Ebola Vaccine Trial Gets Underway at Oxford University

Ebola Vaccine Trial Gets Underway at Oxford University

AFP (Sep. 17, 2014) A healthy British volunteer is to become the first person to receive a new vaccine for the Ebola virus after US President Barack Obama called for action against the epidemic and warned it was "spiralling out of control." Duration: 01:02 Video provided by AFP
Powered by NewsLook.com
Obesity Rates Steady Even As Americans' Waistlines Expand

Obesity Rates Steady Even As Americans' Waistlines Expand

Newsy (Sep. 17, 2014) Researchers are puzzled as to why obesity rates remain relatively stable as average waistlines continue to expand. Video provided by Newsy
Powered by NewsLook.com
President To Send 3,000 Military Personnel To Fight Ebola

President To Send 3,000 Military Personnel To Fight Ebola

Newsy (Sep. 16, 2014) President Obama is expected to send 3,000 troops to West Africa as part of the effort to contain Ebola's spread. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins