Jan. 19, 2005 - Old dogs, as well as humans, may be able to learn new tricks after all.
A new study suggests that the right diet, exercise, and mental stimulation can help even over-the-hill minds stay in shape and learn new things.
Researchers found that older beagles that were fed a diet rich in antioxidants from fruits and vegetables, exercised daily, interacted with others, and played with stimulating toys were more likely to learn new tasks easily as well as score better on learning skills tests.
"The combination of an antioxidant diet and lots of cognitive stimulation -- which was almost the equivalent of going to school every day -- really did improve brain function in these animals," says Molly Wagster, PhD, of the National Institute on Aging's Neuropsychology of Aging Branch, in a news release. "We're excited about these findings because the interventions themselves are relatively simple and might be easily translated into clinical practice for people."
The results of the study appear in the January issue of Neurobiology of Aging.
Helping Old Dogs Learn New Tricks
In the two-year study, researchers divided 48 beagles ranging in age from 7 to 11 years into four groups:
- Group one was fed a regular diet and got standard care.
- Group two received standard care but was fed an antioxidant-fortified diet consisting of standard dog food supplemented with tomatoes, carrot granules, citrus pulp, and spinach flakes and fortified with vitamin E, vitamin C, lipoic acid, and carnitine.
- Group three was fed a regular diet, but received regular exercise, socialization with other dogs, and stimulating toys.
- Group four got both the antioxidant-fortified diet and the enriched environment.
The fruits and vegetables added to the antioxidant-fortified diet was the equivalent of increasing intake from three servings to five or six servings daily.
As the study progressed, researchers tested the dogs with progressively more difficult learning skills tests, such as hiding a treat under a black or white block and then reversing the task so the dog would have to relearn where the treat was hidden.
The results showed that older dogs that ate the antioxidant-fortified diet and lived in an active, stimulating environment did the best on the learning skill tasks and outperformed the dogs in the other groups. But older beagles that received at least one of the interventions, such as diet or exercise, also did better than the group that received standard care and a regular diet.
For example, all 12 of the beagles in the combined diet and enriched environment group were able to solve the reversal learning problem. Eight of the 12 dogs that got the antioxidant-fortified diet solved the problem, and eight of the 10 that lived in the enriched environment without the antioxidant diet solved it. But only two of the dogs in the control group were able to solve the problem.
Researchers also found that the dietary intervention seemed to have no effect on the younger dogs.
"This research brings a note of optimism that there are things that we can do that may significantly improve our cognitive health," says Wagster. "In this case, more was better. Although each factor alone was capable of improving cognitive function in older animals, the combination was additive, pointing to a healthy lifestyle as the most beneficial approach. While we have yet to demonstrate these benefits in people, research such as this gives us new ways to think about the aging brain and what we can do to keep it intact."