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Monkeys and beagles were central to recent studies linking regular physical activity and an enhanced diet to improved brain function.
The monkeys participated in an Oregon Health and Science University study. It showed primates that exercised regularly - using a treadmill five days per week - had a higher brain capillary volume after 20 weeks than a control group that did not exercise. Also, monkeys in the exercise group more rapidly learned new tasks. The study showed that the most significant brain benefits were experienced by monkeys deemed "least fit" at the start of the trial.
The Oregon researchers said studying monkeys eliminates any skewing from the decidedly human behaviors of smoking, drinking and overeating. The findings were discussed at the annual meeting of the Society for Neuroscience this month in New Orleans.
Another new study employed 39 beagles to test the brain-enhancing effectiveness of antioxidant-rich foods (especially those rich in vitamins C and E and beta carotene). University of Toronto researchers discovered that old dogs might possibly even learn some new tricks with the proper fortified food in their dinner bowls.
"We found old dogs on the antioxidant diet performed better on a variety of cognitive tests than dogs not on the diet," said P. Dwight Tapp, a study co-author now based at the University of California at Irvine. "In fact, the dogs eating the antioxidant-fortified foods performed as well as young beagles."
For the uninitiated - or those of us who have never lived with an old beagle or other canines - dogs can experience the same memory loss and slowed cognitive function that occur in humans.
Tapp and colleagues found that the antioxidant-rich diet helped improve cognitive skills in old dogs but not young dogs. A follow-up study is ongoing to determine if feeding the younger dogs the special diet helps prevent loss of brain function.
Arthur F. Kramer figures to stick with humans in his brain research. Kramer is a professor of psychology at the University of Illinois at Urbana-Champaign. He was lead author on a pioneering study published earlier this year that showed positive physiological changes in brain matter due to regular exercise.
The typical man or woman loses brain matter as part of the aging process. In a first, Kramer and colleagues used magnetic-resonance imaging (MRI) scans to show that individuals 55 and older who exercise regularly - walking briskly for 20 minutes three times per week - can preserve gray- and white-matter regions of the brain.
"The great thing is it doesn't take too long to realize these benefits," Kramer said. "We saw significant cognitive improvement in people 55 and older over just six months."
Gray matter consists of a series of thin tissue layers in brain cells such as neurons that are critical to learning and memory. White matter is found in the myelin sheath containing nerve fibers that transmit signals throughout the brain. As people age, beginning after 30, the two types of matter shrink in a pattern closely matched by decreased cognitive performance, Kramer said.
Kramer and his colleagues have completed other cutting-edge research about the brain and regular physical activity. One study slotted for 2004 publication follows up on the gray/white-matter study. Preliminary results indicate that the same sort of brisk walking will enhance the performance capabilities of cortical circuits in the brain.
"We are reporting on function and not just the physiology of the gray and white matter," Kramer explained.
Another study to be published in 2004 builds on earlier findings that active older women on hormone-replacement therapy exhibit greater cognitive abilities than older men who are regular exercisers. In new findings, Kramer and colleagues have found less actual brain tissue deterioration in women 55 and older who have higher levels of estrogen in their bodies.
Despite being a "former jock," Kramer didn't expect that his research career would turn so directly toward fitness and physical activity. He has become a leading researcher in the area during the last decade and, along with several colleagues, turned the University of Illinois into a respected center for research on healthy aging.
"There is no downside to physical activity for older adults who get clearance from their physicians to start a program," he said.
"We know it can help prevent heart disease and protect against stroke damage. Now we are building evidence that regular physical activity allows you to think better."
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(Bob Condor writes for the Chicago Tribune. Write to him at: the Chicago Tribune, 435 N. Michigan Ave., Chicago, Ill. 60611.)
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(c) 2003, Chicago Tribune. Distributed by Knight Ridder/Tribune News Service.
