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:4/29/2016)... Georgia (PRWEB) , ... April 29, 2016 , ... On ... rural hospitals across the Southeast, celebrated the signature of Gov. Nathan Deal on SB ... Rep. Geoff Duncan (R - Cumming), offers a 70% tax credit to individuals and ...
(Date:4/29/2016)... Fort Stewart, GA (PRWEB) , ... April 29, 2016 , ... ... on Monday, May 16, 2016, at its new location in the Exchange Furniture Mall ... including a raffle for a 50-inch Samsung Smart TV. Plus attendees will have the ...
(Date:4/29/2016)... ... April 29, 2016 , ... World Patent Marketing , ... exercise invention which aids in proper muscle development. , "The Gym & Exercise ... Director of World Patent Marketing. "Globalization has threatened the future growth of the ...
(Date:4/29/2016)... (PRWEB) , ... April 29, 2016 , ... Reltok Nasal ... and products for the head and neck/ear, nose and throat specialty, has added the ... The KOTLER NASAL AIRWAY™ is a newly patented safety device secured by ...
(Date:4/29/2016)... ... April 29, 2016 , ... CURE ... entirely on patients with cancer, today announced that Lynne Malestic, RN, of Eisenhower ... 2016 CURE® Extraordinary Healer® for Oncology Nursing , which honors nurses who have ...
Breaking Medicine News(10 mins):
(Date:4/28/2016)... April 28, 2016  The blood testing market in ... according to Kalorama Information and The Freedonia Group in ... nucleic acid testing.  The healthcare research firm said that ... developing blood collection stations and in improving testing at ... Information,s report, Blood Testing Market in China ...
(Date:4/28/2016)... 28, 2016 Dr. Vivek Ahuja ... and Ste phen Schmidt ... leading provider of cloud-based software solutions for life sciences, today announced ... bring a wealth of insight to a growing business.  This will ... George Phillips joined ArisGlobal in the position of ...
(Date:4/28/2016)... April 28, 2016  ValGenesis, Inc., the ... Solutions (VLMS) today announced that a prominent ... sufferers of chronic kidney failure has selected ... their corporate validation process. The global medical ... solution to manage their validation processes electronically. ...
Breaking Medicine Technology: