Navigation Links
Antioxidants Blunt Exercise Benefit, Study Shows
Date:5/11/2009

Vitamins C, E block creation of free radicals that promote insulin sensitivity, researchers say,,,,

MONDAY, May 11 (HealthDay News) -- Exercise helps increase insulin sensitivity and ward off diabetes, but taking supplemental antioxidants such as vitamins C and E actually blunts that benefit, researchers report.

Exercise helps increase the body's sensitivity to insulin by making reactive oxygen species, or "free radicals," which antioxidants work against. These free radicals are thought to damage cells and speed the aging process, but they are also used by the body to prevent cell damage after exercising, the researchers say.

"When you exercise you do improve your insulin sensitivity, and if you are at risk for diabetes improving insulin sensitivity is good," said researcher Dr. C. Ronald Kahn, the Mary K. Iacocca Professor at the Joslin Diabetes Center and Harvard Medical School.

Part of the reason that exercise improves insulin sensitivity is that it causes oxidative stress on the muscles. The muscles respond to this stress by creating free radicals, Kahn said.

"If you take antioxidants like vitamins C and E, you block the oxidative stress response, but you also block the beneficial effects of exercise on insulin sensitivity," he said.

The report is published in this week's online edition of the Proceedings of the National Academy of Sciences.

For the study, Kahn's team looked at the benefit of exercise in increasing insulin resistance in 39 young men, roughly half of whom were taking supplemental vitamins C and E.

Kahn's group found that men taking vitamin supplements had no change in their insulin resistance, but men not taking vitamins had an increase in free radicals, which increases insulin resistance. A month after stopping the vitamin supplements insulin sensitivity was restored, the researchers noted.

"If you are exercising, in part, to reduce diabetes risk, you shouldn't take vitamin C and E, because you are going to block some of the beneficial effect of the exercise to prevent the diabetes," Kahn said.

Dr. David L. Katz, director of the Prevention Research Center at Yale University School of Medicine, thinks this study raises doubts about the benefits of taking antioxidant supplements, but not about the value of these vitamins in the foods people eat.

"We have long held out hope that antioxidant supplements, among them vitamin C, vitamin E, beta carotene, and more recently lycopene and others, would help prevent diseases from the common cold to cancer, heart disease to diabetes," Katz said. "But to date, virtually all of the best research evidence is contrary to this hope."

This study has a counter-intuitive conclusion, namely that antioxidant supplements may actually interfere with the beneficial effects of exercise on insulin sensitivity, Katz said.

"This is a small and short-term study, and thus cannot tell us definitively that antioxidant supplements are harmful in diabetes or the insulin-resistant state that often precedes it. But that is precisely what the study suggests may be true," Katz said.

For now, there is substantial uncertainty about any health benefits and the potential harms of antioxidants as supplements, Katz said. "But we have no such confusion about the powerful health-promoting effects of wholesome, mostly plant-based diets and regular physical activity."

More information

For more information on antioxidants, visit the U.S. National Library of Medicine.



SOURCES: C. Ronald Kahn, M.D., Mary K. Iacocca Professor, Joslin Diabetes Center and Harvard Medical School, Boston; David L. Katz, M.D., M.P.H., director, Prevention Research Center, Yale University School of Medicine, New Haven, Conn.; May 11-15, 2009, Proceedings of the National Academy of Sciences, online


'/>"/>
Copyright©2009 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. Brooke Shields and the Makers of COPPERTONE(R) Join Together to Launch COPPERTONE(R) NutraShield(TM) - New Sunscreen Contains Antioxidants That Promote Natural Skin Repair
2. Antioxidants offer pain relief in patients with chronic pancreatitis
3. Coromega Unveils New Healthy Heart and CoQ10 Supplements : Revolutionary Omega-3 Supplement Company Introduces Two Fresh Takes on Heart Health and Antioxidants
4. Too Much Sun, Too Few Antioxidants Spell Eye Trouble
5. Cancer Patients Should Steer Clear of Antioxidants
6. Dr. William S. Gruss, M.D., Says That Medical Research Shows You Can Reduce Your Risk of Cancer By Up To 77% and Reverse the Effects of Aging in A CARDIOLOGISTS GUIDE TO ... ANTI-AGING, ANTIOXIDANTS & RESVERATROL
7. Alimera Sciences Signs Second Agreement With Emory University for Potential Treatments Using New Class of Antioxidants
8. Citrus Juice Gives Boost to Green Tea Antioxidants
9. Natural Antioxidants Help Reduce Oxidative Stress in Diabetes Treatment
10. Citrus juice, vitamin C give staying power to green tea antioxidants
11. Antioxidants do not prevent degenerative eye disease
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Antioxidants Blunt Exercise Benefit, Study Shows
(Date:5/26/2017)... Massachsetts (PRWEB) , ... May 26, 2017 , ... ... will gather at Boston CEO 2017 on May 30th and 31st at The ... networking forum for leading executives in the life sciences, offering exclusive access to ...
(Date:5/26/2017)... ... May 26, 2017 , ... A new analysis of community health data reveals ... located in the Midwest. With the average cost of healthcare rising and the U.S. ... both the quality and affordability of where they live. An annual 2017 report looked ...
(Date:5/26/2017)... (PRWEB) , ... May 26, 2017 , ... After raising ... Antzy Top gadget will continue to be available at a discounted crowdfunding price on ... with stress wherever they are, I also wanted to bring a fidget toy to ...
(Date:5/26/2017)... ... 26, 2017 , ... Dr. Alex Rabinovich, a highly-skilled oral surgeon specializing in ... post on insurance options. If a Bay Area patient has to search for a ... money. Visiting an in-network provider for a second opinion can ensure a patient receives ...
(Date:5/26/2017)... ... ... Happened in the Garden of Eden”: retells the stories of three Bible figures in modern ... author, Penelope Colt, mother, trader, horse farmer, artist and a former GM journeyman. Born ... At six, they moved to Dayton, Ohio, where Penny graduated high school. At sixteen, ...
Breaking Medicine News(10 mins):
(Date:5/6/2017)... N.Y. , May 5, 2017  Hill-Rom Holdings, ... will add approximately 100,000 square feet to its Welch ... September 2016 its commitment to bring more than 100 ... , where Welch Allyn has maintained a significant presence ... help accommodate these new positions, a large portion of ...
(Date:5/4/2017)... CAESAREA, Israel , May 4, 2017  DarioHealth ... with mobile health and big data solutions, today announced ... an A&D Company, and STI Technologies Limited to lower ... effective immediately. Through STI,s innoviCares card, which is available ... , DarioHealth customers will be eligible for additional ...
(Date:5/3/2017)... 3, 2017  Getinge, a leading global provider ... enhancement and cost efficiency within healthcare and life ... contemporary practice demonstrating that intra-aortic balloon counterpulsation (IABC) ... ill patients. The single-center, retrospective, observational study showed ... MEGA ® 50cc intra-aortic balloon (IAB) in ...
Breaking Medicine Technology: