Tuesday, April 27, 2010

Mediterranean Diet Helps Protect Aging Brain

People who scored highest in adherence to diet least likely to suffer mental decline, study finds

TUESDAY, April 27 (HealthDay News) -- Eating a Mediterranean diet may help keep your brain healthy as you age, findings from an ongoing study show.
"This diet emphasizes vegetables, fruits, fish, olive oil, lower meat consumption, and moderate wine and non-refined grain intake," study author Dr. Christy Tangney, of Rush University Medical Center in Chicago, said in a news release from the American Society for Nutrition.
Rather than asking people to avoid certain foods, the study found data that "adults over age 65 should look to include more olive oil, legumes, nuts, and seeds in their diet in order to improve their recall times and other cognitive skills, such as identifying symbols and numbers," Tangney said.
The study included 4,000 adults aged 65 and older who were given a series of tests to examine their cognitive (or thinking) skills every three years over a 15-year period. Those who scored highest in following a Mediterranean diet were least likely to suffer cognitive decline, the study authors found.
"We [also] want older adults to remember that physical activity is an important part of maintaining cognitive skills," Tangney added.

Regular aerobic exercise keeps the brain healthy

Washington, DC: Regular aerobic exercise improves blood flow to the brain and speeds learning process, says a new study.

The study led by researchers from the University of Pittsburgh School of Medicine is the first to examine these relationships in a non-human primate model. The finding is available in the journal Neuroscience.

While there is ample evidence of the beneficial effects of exercise on cognition in other animal models, such as the rat, it has been unclear whether the same holds true for people, said senior author Judy L. Cameron, Ph.D., a psychiatry professor at Pitt School of Medicine and a senior scientist at the Oregon National Primate Research Center at Oregon Health and Science University. Testing the hypothesis in monkeys can provide information that is more comparable to human physiology.

"We found that monkeys who exercised regularly at an intensity that would improve fitness in middle-aged people learned to do tests of cognitive function faster and had greater blood volume in the brain's motor cortex than their sedentary counterparts," Dr Cameron said. "This suggests people who exercise are getting similar benefits."

To reach the conclusion, researchers trained adult female cynomolgus monkeys to run on a human-sized treadmill at 80 percent of their individual maximal aerobic capacity for one hour each day, five days per week, for five months. Another group of monkeys remained sedentary, meaning they sat on the immobile treadmill, for a comparable time. Half of the runners went through a three-month sedentary period after the exercise period. In all groups, half of the monkeys were middle aged (10 to 12 years old) and the others were more mature (15 to 17 years old). Initially, the middle-aged monkeys were in better shape than their older counterparts, but with exercise, all the runners became more fit.

During the fifth week of exercise training, standardized cognitive testing was initiated and then performed five days per week until week 24. In a preliminary task, the monkeys learned that by lifting a cover off a small well in the testing tray, they could have the food reward that lay within it. In a spatial delay task, a researcher placed a food reward in one of two wells and covered both wells in full view of the monkey. A screen was lowered to block the animal's view for a second, and then raised again. If the monkey displaced the correct cover, she got the treat. After reliably succeeding at this task, monkeys that correctly moved the designated one of two different objects placed over side-by-side wells got the food reward that lay within it.

"Monkeys that exercised learned to remove the well covers twice as quickly as control animals," Dr. Cameron said. "Also, they were more engaged in the tasks and made more attempts to get the rewards, but they also made more mistakes."

She noted that later in the testing period, learning rate and performance was similar among the groups, which could mean that practice at the task will eventually overshadow the impact of exercise on cognitive function.

When the researchers examined tissue samples from the brain's motor cortex, they found that mature monkeys that ran had greater vascular volume than middle-aged runners or sedentary animals. But those blood flow changes reversed in monkeys that were sedentary after exercising for five months.

"These findings indicate that aerobic exercise at the recommended levels can have meaningful, beneficial effects on the brain," Dr. Cameron said. "It supports the notion that working out is good for people in many, many ways."

Human brain recognizes and reacts to different races

The human brain reacts differently when dealing with people of another race, says a new study.
This research, conducted by scientists at the University of Toronto (U of T), had participants view a series of videos while hooked up to electroencephalogram (EEG) machines. An EEG measures brain activity.
The participants - all white - watched simple videos in which men of different races picked up a glass and took a sip of water. They watched white, black, South Asian and East Asian men perform the task.
Typically, when people observe others perform a simple task, their motor cortex region fires similarly to when they are performing the task themselves. The motor cortex controls the planning and execution of a movement.
However, the research team, led by doctoral student Jennifer Gutsell and Michael Inzlicht, assistant professor, found that participants' motor cortex was significantly less likely to fire when they watched the minority men perform the simple task.
In some cases when participants watched the non-white men performing the task, their brains actually registered as little activity as when they watched a blank screen.
'Previous research shows people are less likely to feel connected to people outside their own ethnic groups, and we wanted to know why,' says Gutsell.
'What we found is that there is a basic difference in the way peoples' brains react to those from other ethnic backgrounds.'
'Observing someone of a different race produced significantly less motor-cortex activity than observing a person of one's own race. In other words, people were less likely to mentally simulate the actions of other-race than same-race people,' says Gutsell.
The trend was even more pronounced for participants who scored high on a test measuring subtle racism, says Gutsell.
These findings were published in the Journal of Experimental Social Psychology.