Antioxidants – Help or Hype – Part 2

October 23, 2011 by foodworksblog 3 Comments

Image via Wikipedia

A detailed analysis of human studies of beta-carotene, vitamin A, and vitamin E shows that people who take these antioxidant supplements don’t live any longer than those who don’t take them. In fact, those who take the supplements have an increased risk of death. The study reported in the Journal of the American Medical Association, is authored by Goran Bjelakovic, MD, DrMedSci, of the University of Nis in Serbia; Christian Gluud, MD, DrMedSci, of Copenhagen University Hospital in Denmark; and colleagues.

The researchers looked at 47 “low bias risk” studies — which included nearly 181,000 participants. They found that:

• Taking vitamin A supplements increased the risk of death by 16%.
• Taking beta-carotene supplements increased the risk of death by 7%.
• Taking vitamin E supplements increased the risk of death by 4%.
• Taking vitamin C supplements did not have any effect on risk of death.

“According to our findings, beta-carotene, vitamin A, and vitamin E cannot be recommended. I am telling my patients that they should stop using these supplements.”

“There is no reason to take anything that hasn’t been proven beneficial. And these antioxidant supplements do not seem beneficial at all,” Gluud  stated.

Edgar R. Miller III, MD, PhD, associate professor of medicine at Johns Hopkins University, in 2004 analyzed clinical trials of vitamin E. He found that high doses of vitamin E did more harm than good.  As reported in a previous blog, there have been problems with vitamin E intake and prostate cancer and older women taking multivitamin supplements had a slightly higher risk of death, and beta carotene supplements were associated with a higher risk of lung cancer in smokers.

ON THE OTHER HAND

Not everyone agrees. Not surprisingly at that time, nutritional biochemist.  Andrew Shao, PhD, and former vice president for scientific and regulatory affairs at the Council for Responsible Nutrition, a supplement-industry trade group was quoted as:

“Consumers can feel confident in relying on their antioxidant supplements as they always have,” Shao notes. “They can continue to take them knowing they will provide the same benefits — and this article does not change that.”

Shao says it just isn’t fair to study antioxidants in this way. “What these authors have done is combine studies that are incredibly dissimilar in all sorts of ways,” he says. “These studies looked at different nutrients at different doses at different durations with different lengths of follow-up — and in different populations, ranging from folks who were incredibly healthy to people with cancer and other diseases.”

“These questions cause one to step back and wonder if the findings are relevant to the healthy population that uses these supplements to maintain health and avoid chronic disease,” Shao says. “That is a point they don’t make: that antioxidants are not used to treat cancer or heart disease. They are used for disease prevention.”

Currently, Shao has been named as VP for Global Product Science and Safety for the direct-to-consumer distributor of Herbalife supplements.

Gluud and Bjelakovic strongly disagree with some critics that say that they “cherry picked” only studies that fit some preconceived conclusion. They point out that all of their methods are “transparent” and open to public view.

“Anyone is welcome to criticize our research,” Gluud says. “But my question is, what is your evidence? I think the parties that want to sell or use these antioxidant supplements in the dosages used in these trials, they want to see only positive evidence that it works beneficially.”

The authors concluded that their findings contradicted other studies that claimed that antioxidants improved health.  The noted that these studies should be assessed carefully since 80-160 million adults in North America and Europe consume these supplements, resulting in public health issues.

They offered some explanations for the negative effects they found.  Since oxidative stress has been hypothesized to contribute to many chronic diseases, it may be simply that if we interfere with elimination of free radicals in the body, we may also interfere with important defensive mechanisms already present in the body. This could include immune defenses, natural cell death, or detoxification of harmful substances, processes that use free radicals to help the body perform these important functions.  Antioxidant supplements are synthetic and their mechanisms and actions may not be equal with the “natural” effects of antioxidants found in fruits and vegetables.

Consumers should make their own decisions as to whether they need or should use nutrition supplements, based on their own diet assessments and knowing the research findings on this controversial topic.  There are good points to be made on both sides.  So until, further investigations report either positive or negative effects of dietary supplements, at least EAT YOUR FRUITS AND VEGETABLES.