Navigation Links
Forget the antioxidants? McGill researchers cast doubt on role of free radicals in aging
Date:2/17/2009

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
mark.shainblum@mcgill.ca
514-398-2189
McGill University
Source:Eurekalert

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:
*Name:
*Comment:
*Email:
(Date:5/6/2017)... 5, 2017 RAM Group , ... new breakthrough in biometric authentication based on a ... properties to perform biometric authentication. These new sensors are ... created by Ram Group and its partners. This sensor ... supply chains and security. Ram Group is a ...
(Date:4/18/2017)... 18, 2017  Socionext Inc., a global expert in SoC-based imaging ... server, the M820, which features the company,s hybrid codec technology. A ... Tera Probe, Inc., will be showcased during the upcoming Medtec Japan ... at the Las Vegas Convention Center April ... Click here for ...
(Date:4/13/2017)... , April 13, 2017 According to a ... Identity Authentication, Identity Analytics, Identity Administration, and Authorization), Service, Authentication Type, Deployment ... the IAM Market is expected to grow from USD 14.30 Billion in ... Rate (CAGR) of 17.3%. ... MarketsandMarkets Logo ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... ... October 12, 2017 , ... BioMedGPS announces ... addition of its newest module, US Hemostats & Sealants. , SmartTRAK’s US Market ... hemostats, fibrin sealants, synthetic sealants and biologic sealants used in surgical applications. BioMedGPS ...
(Date:10/12/2017)... ... October 12, 2017 , ... ... genomics analysis platform specifically designed for life science researchers to analyze and ... researcher Rosalind Franklin, who made a major contribution to the discovery of ...
(Date:10/11/2017)... ... October 11, 2017 , ... The CRISPR-Cas9 system ... experiments and avoiding the use of exogenous expression plasmids. The simplicity of programming ... systematic gain-of-function studies. , This complement to loss-of-function studies, such as with ...
(Date:10/11/2017)... ... October 11, 2017 , ... ComplianceOnline’s Medical Device Summit is ... and 8th June 2018 in San Francisco, CA. The Summit brings together current and ... distinguished CEOs, board directors and government officials from around the world to address key ...
Breaking Biology Technology: