SAN DIEGO (AP) _ Studies exploring the effects of specific foods on the brains of animals found that diets rich in spinach and blueberries may help stave off age-related declines in rats' mental abilities.
Rats fed a diet rich in spinach reversed a normal loss of learning that occurs with age, according to a study by researchers at the University of South Florida. The study was presented at the Society for Neuroscience's annual meeting in San Diego this week.
Rats fed a normal diet that contained 2 percent freeze-dried spinach learned to associate the sound of a tone with an oncoming puff of air faster than those fed regular rat chow, the study found.
The test measured the interval between the sound of the tone and when the rats blinked, and was designed to test the ability to associate two distinct but related events. The speed of the reaction has been shown to decline with age in rodents, rabbits and humans.
Spinach is rich in antioxidants, which scientists say can block the effects of free radicals. Studies suggest the lifelong accumulation of free radicals in the brain is linked to mental declines in old age and is also a probable factor in Alzheimer's and Parkinson's diseases.
``This is a preclinical finding of significant interest that now needs to be tested in humans,'' said Dr. Paula Bickford of the University of South Florida, an author of the study.
Blueberries are also rich in antioxidants. A study by researchers at the University of Houston at Clear Lake and the Universidad Nacional Autonoma de Mexico found that blueberries may help fight age-related declines in rats' memories.
Aging rats that were fed a blueberry-supplemented diet for four months tested as well as younger rats in their abilities to recognize objects after an hour. Aging rats fed a normal diet failed to recognize the objects.
``This research has rather hopeful implications for prevention of neurological or psychological disorders in our increasingly aging population,'' said Dr. David Malin of the University of Houston, Clear Lake.
The brains of the rats in the experiment are being analyzed to determine whether blueberries slowed brain degeneration.