Navigation Links
Forget the antioxidants? McGill researchers cast doubt on role of free radicals in aging

This release is available in French.

For more than 40 years, the prevailing explanation of why we get old has been tied to what is called oxidative stress. This theory postulates that when molecules like free radicals, oxygen ions and peroxides build up in cells, they overwhelm the cells' ability to repair the damage they cause, and the cells age.

An industry of "alternative" antioxidant therapies -- such as Vitamin E or CoQ10 supplements in megadose format --has sprung up as the result of this theory. However, clinical trials have not shown that these treatments have statistically significant effects.

And now researchers at McGill University, in a study published in the February issue of the journal PLoS Genetics, are calling the entire oxidative stress theory into question. Their results show that some organisms actually live longer when their ability to clean themselves of this toxic molecule buildup is partially disabled. Collectively, these molecules are known as reactive oxygen species, or ROS for short.

Dr. Siegfried Hekimi of McGill's Department of Biology, said most of the evidence for the oxidative stress theory is circumstantial, meaning oxidative stress could just as easily be a result of aging as its cause.

"The problem with the theory is that it's been based purely on correlative data, on the weight of evidence," explained Hekimi, McGill's Strathcona Chair of Zoology and Robert Archibald & Catherine Louise Campbell Chair in Developmental Biology. "It is true that the more an organism appears aged, whether in terms of disease, or appearance or anything you care to measure, the more it seems to be suffering from oxidative stress".

"This has really entrenched the theory," he continued, "because people think correlation is causation. But now this theory really is in the way of progress."

Hekimi and postdoctoral fellow Jeremy Van Raamsdonk studied mutant Caenorhabditis elegans worms. They progressively disabled five genes responsible for producing a group of proteins called superoxide dismutases (SODs), which detoxify one of the main ROS. Earlier studies seemed to show that decreased SOD production shortened an organism's lifespan, but Hekimi and Van Raamsdonk did not observe this. In fact, they found quite the opposite.

None of their mutant worms showed decreased lifespan compared to wild-type worms, even though oxidative stress was clearly raised. In fact, one variety actually displayed increased lifespan, the researchers said.

"The mutation that increases longevity affects the main SOD found in mitochondria inside the animals' cells," said Hekimi. "This is consistent with earlier findings that mitochondria are crucial to the aging process. It seems that reducing mitochondrial activity by damaging it with ROS will actually make worms live longer."

The researchers hasten to point out that they are not suggesting that oxidative stress is good for you.

"ROS undoubtedly cause damage to the body," Hekimi said. "However, they do not appear to be responsible for aging."


Contact: Mark Shainblum
McGill University

Related biology news :

1. Dont forget the vitamin A when working with its carrier protein
2. Fighting Aussie yabbies dont forget a face -- new research by the University of Melbourne
3. When accounting for the global nitrogen budget, dont forget fish
4. MUHC and McGill scientists explain genetic disease first discovered in Quebec 24 years ago
5. Key to curing obesity may lie in worms that destroy their own fat: McGill researchers
6. Boost from McGill, Gates Foundation helps Africans control pharma research
7. McGill conference on Global Food Crisis draws impressive list of international participants
8. Oceanographer Dennis J. McGillicuddy, Jr. receives 34th annual Rosenstiel Award
9. Tiny genetic differences have huge consequences: McGill researchers
10. Type 1 diabetes triggered by lazy regulatory T-cells: McGill researchers
11. 12 McGill researchers awarded Canada Research Chairs
Post Your Comments:
(Date:5/3/2016)...  Neurotechnology, a provider of high-precision biometric identification ... Identification System (ABIS) , a complete system for ... can process multiple complex biometric transactions with high ... face or iris biometrics. It leverages the core ... MegaMatcher Accelerator , which have been used in ...
(Date:4/26/2016)... LONDON , April 26, 2016 /PRNewswire/ ... Systems, a product subsidiary of Infosys (NYSE: ... partnership to integrate the Onegini mobile security platform ... ) The integration ... security to access and transact across channels. Using ...
(Date:4/15/2016)... April 15, 2016  A new partnership announced ... accurate underwriting decisions in a fraction of the ... priced and high-value life insurance policies to consumers ... With Force Diagnostics, rapid testing (A1C, Cotinine ... readings (blood pressure, weight, pulse, BMI, and activity ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... (PRWEB) , ... June 23, 2016 , ... ... on quality, regulatory and technical consulting, provides a free webinar on ... on July 13, 2016 at 12pm CT at no charge. , Incomplete investigations ...
(Date:6/23/2016)... , June 22, 2016  Amgen (NASDAQ: ... the QB3@953 life sciences incubator to accelerate ... The shared laboratory space at QB3@953 was created to ... key obstacle for many early stage organizations - access ... the sponsorship, Amgen launched two "Amgen Golden Ticket" awards, ...
(Date:6/22/2016)... , June 22, 2016 Cell ... will allow them to produce up to one ... one lot within one week. These high-quality, consistent ... laboriously preparing cells and spend more time doing ... through a proprietary, high-volume manufacturing process that produces ...
(Date:6/22/2016)... 22, 2016  According to Kalorama Information, the ... (NGS) market include significant efforts in automation as ... accessible and affordable sequencers, say the healthcare market ... consumables including sample prep materials.  The healthcare market ... Preparation for Next Generation Sequencing (NGS) , highlights ...
Breaking Biology Technology: