Antioxidants aren't always good for you and can impair muscle function, study shows

Jan 26, 2010

Antioxidants increasingly have been praised for their benefits against disease and aging, but recent studies at Kansas State University show that they also can cause harm.

Researchers in K-State's Cardiorespiratory Exercise Laboratory have been studying how to improve oxygen delivery to the skeletal muscle during physical activity by using antioxidants, which are nutrients in foods that can prevent or slow the oxidative damage to the body. Their findings show that sometimes antioxidants can impair .

"Antioxidant is one of those buzz words right now," said Steven Copp, a doctoral student in anatomy and physiology from Manhattan and a researcher in the lab. "Walking around grocery stores you see things advertised that are loaded with antioxidants. I think what a lot of people don't realize is that the antioxidant and pro-oxidant balance is really delicate. One of the things we've seen in our research is that you can't just give a larger dose of antioxidants and presume that there will be some sort of beneficial effect. In fact, you can actually make a problem worse."

David C. Poole and Timothy I. Musch, K-State professors from both the departments of kinesiology and anatomy and physiology, direct the Cardiorespiratory Exercise Laboratory, located in the College of Veterinary Medicine complex. Researchers in the lab study the physiology of physical activity in health and disease through animal models. Copp and Daniel Hirai, an anatomy and physiology doctoral student from Manhattan working in the lab, have conducted various studies associated with how muscles control blood flow and the effects of different doses and types of antioxidants.

Abnormalities in the , such as those that result from aging or a disease like , can impair oxygen delivery to the and increase fatigability during , Copp said. The researchers are studying the effects antioxidants could have in the process.

"If you have a person trying to recover from a heart attack and you put them in cardiac rehab, when they walk on
a treadmill they might say it's difficult," Poole said. "Their muscles get sore and stiff. We try to understand why the blood cells aren't flowing properly and why they can't get oxygen to the muscles, as happens in healthy individuals."

Copp said there is a potential for antioxidants to reverse or partially reverse some of those changes that result from aging or disease. However, K-State's studies have shown that some of the oxidants in our body, such as hydrogen peroxide, are helpful to increase blood flow.

"We're now learning that if antioxidant therapy takes away hydrogen peroxide - or other naturally occurring vasodilators, which are compounds that help open blood vessels - you impair the body's ability to deliver oxygen to the muscle so that it doesn't work properly," Poole said.

Poole said antioxidants are largely thought to produce better health, but their studies have shown that antioxidants can actually suppress key signaling mechanisms that are necessary for muscle to function effectively.

"It's really a cautionary note that before we start recommending people get more antioxidants, we need to understand more about how they function in physiological systems and circumstances like exercise," Poole said.

Hirai said the researchers will continue to explore and the effects of exercise training. Their studies are looking at how these can help individuals combat the decreased mobility and muscle function that comes with advancing age and diseases like .

"The research we do here is very mechanistic in nature, and down the road our aim is to take our findings and make recommendations for diseased and aging populations," Copp said.

Explore further: Scientists identify critical new protein complex involved in learning and memory

More information: The researchers have published their recent findings in several journals, including the Journal of Applied Physiology, Respiratory Physiology and Neurobiology, Microvascular Research, The American Journal of Physiology and Experimental Physiology.

add to favorites email to friend print save as pdf

Related Stories

Honeydew honeys are better antioxidants than nectar honeys

Feb 22, 2007

A study of 36 Spanish honeys from different floral origins revealed that honeys generated by bees feeding on honeydew have greater antioxidant properties than those produced by bees feeding on nectar. The study is published ...

Study: Antioxidants may slow vision loss

Jul 19, 2006

U.S. scientists say they've blocked the advance of retinal degeneration in mice with a form of retinitis pigmentosa by treating them with antioxidants.

Recommended for you

How the body fights against viruses

14 hours ago

Scientists of the Max F. Perutz Laboratories of the University of Vienna and the Medical University of Vienna, together with colleagues of the ETH Zurich, have now shown how double stranded RNA, such as viral ...

Fast way to measure DNA repair

20 hours ago

Our DNA is under constant attack from many sources, including environmental pollutants, ultraviolet light, and radiation. Fortunately, cells have several major DNA repair systems that can fix this damage, ...

Protein expression gets the heart pumping

22 hours ago

Most people think the development of the heart only happens in the womb, however the days and weeks following birth are full of cellular changes that play a role in the structure and function of the heart. ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Caliban
1 / 5 (1) Jan 26, 2010
Fact is, you'd have to really load up on the antioxidants to throw things out of balance, and the more so with diets progressively higher in processed foods. this article overstates the case.

eat some fruit. have some tea. have some veggies. have some red wine with dinner. RELAX.

More news stories

Volitional control from optical signals

(Medical Xpress)—In their quest to build better BMIs, or brain-machine-interfaces, researchers have recently begun to look closer at the sub-threshold activity of neurons. The reason for this trend is that ...

Neuroimaging: Live from inside the cell

A novel imaging technique provides insights into the role of redox signaling and reactive oxygen species in living neurons, in real time. Scientists of the Technische Universität München and the Ludwig-Maximilians-Universität ...

Mantis shrimp stronger than airplanes

(Phys.org) —Inspired by the fist-like club of a mantis shrimp, a team of researchers led by University of California, Riverside, in collaboration with University of Southern California and Purdue University, ...