When it comes to diets and nutritional supplements, we’ve come to think of antioxidants as the white hats. With their reputation for fighting the disease-causing bad guys known as free radicals, sales of antioxidant-rich drinks like pomegranate juice and supplements such as beta carotene and vitamin E have flourished.
But, say experts at OMRF, striking the proper biological balance between antioxidants and free radicals is no simple tale of good and evil.
“One major misconception is that free radicals always do bad things,” said Luke Szweda, Ph.D., who chairs the Free Radical Biology and Aging Research Program at OMRF. “But what we’re finding is that suppressing free radicals — the things antioxidants fight — can actually be harmful in some situations.”
Free radicals are produced when cells consume oxygen in the process of making energy. When unchecked, they can cause problems by damaging parts of the cell, and research has linked free radicals with cell death, aging, cancer, heart disease and a variety of neurological disorders, including Alzheimer’s.
“Still, it’s kind of ridiculous to assume that the human body, which is such an elegant machine, would create something that’s only harmful to itself,” said Szweda, who holds the Hille Family Foundation Chair in Neurodegenerative Disease Research at OMRF. “Research shows that free radicals can sometimes act as the canary in a coal mine, tipping off the body that it needs to change cellular function in order to prevent or minimize long-term damage.”
For example, research done by Kenneth Humphries, Ph.D., at OMRF shows that small doses of free radicals can ready the heart for an onslaught of free radicals that comes after cardiac arrest and resuscitation.
“When blood flow to the heart is interrupted or stops completely, it can cause serious damage,” Humphries said. “Sometimes this interruption even leads to death.”
“But damage to heart doesn’t only happen when the blood flow stops, but also when blood flow is suddenly restored,” he said. That process is called reperfusion, and it releases a flood of free radicals that can damage the heart. However, exposing the heart to low levels of free radicals prior to reperfusion can actually activate protective mechanisms to prevent injury.
“Free radicals can act as a signal to some proteins to alter their function,” Szweda said. In a recent collaboration with researchers from the University of Sao Paulo in Brazil published in the Journal of Biological Chemistry, Szweda found that a protein that helps burn oxygen — creating free radicals — is also signaled by free radicals to clean up other free radicals when they reach toxic levels.
“Our bodies create free radicals for all sorts of reasons,” he said. “They can kill certain kinds of bacteria, for one thing. What we’re finding more and more is that they help regulate functions within the body. Unnaturally high levels of antioxidants can block these normal functions and potentially cause other problems.”
So before you flood your body with all the antioxidant-rich products on the market, remember that not everything is so black and white.
“Free radicals can be harmful, but they can be helpful, too,” said Szweda. “Given a sensible diet, the body generally does a good job of striking the right balance between free radical production and removal.”
In disease, that balance is disrupted. “OMRF’s Free Radical Biology and Aging Research Program seeks to understand the good and bad of free radicals,” said Szweda. “This knowledge will help create antioxidant therapies that prevent damage without disturbing the body’s natural defenses.”