October 14, 2010
Walking about six miles a week appears to protect against brain shrinkage in old age, which in turn helps stem the onset of memory problems and cognitive decline, new research reveals.
“We have always been in search of the drug or the magic pill to help treat brain disorders,” noted Kirk I. Erickson, an assistant professor of psychology at the University of Pittsburgh and the study’s lead author. “But really what we are after may be, at least partially, even simpler than that. Just by walking regularly, and so maintaining a little bit of moderate physical activity, you can reduce your likelihood of developing Alzheimer’s disease and [can] spare brain tissue.”
A report on the research, which was supported by the U.S. National Institute on Aging, is published online Oct. 13 in Neurology.
Erickson and his colleagues began tracking the physical activity and cognitive (or thinking) patterns of nearly 300 adults in 1989. At the start, all participants were in good cognitive health, they averaged 78 years old and about two-thirds were women. The researchers charted how many blocks each person walked in a week.
Nine years later, they were given a high-resolution MRI scan to measure brain size. All were deemed to be “cognitively normal.”
But four years after that, testing showed that a little more than one-third of the participants had developed mild cognitive impairment or dementia.
By correlating cognitive health, brain scans and walking patterns, the research team found that being more physically active appeared to marginally lower the risk for developing cognitive impairment.
But more specifically, they concluded that the more someone walks, the more gray matter tissue the person will have a decade or more down the road in regions of the brain — namely the hippocampus, the inferior frontal gyrus and the supplementary motor area — that are central to cognition.
And among the more physically active participants who had retained more gray matter a decade out, the chances of developing cognitive impairment were cut in half, the study found.
However, the researchers stressed that the relationship between walking and gray matter volume appears to apply only to people who regularly walk relatively long distances that equal about six to nine miles a week.
Walking more than the six- to nine-mile range, however, did not have cognitive benefit, the study found.
“That’s because the size of our brain regions can only be so large,” Erickson said, adding that the opposite isn’t true. “So with no exercise, there can be significant deterioration and decay with age.”
However, he added, “what we often tend to think of as an inevitable component or characteristic of aging — memory decline and brain decay — is clearly not inevitable. There’s plenty of evidence now, and this study is part of that, that shows that we can retain our brain tissue and retain our memories well into late adulthood by maintaining an active and engaged lifestyle.”
Dr. Steven V. Pacia, chief of neurology at Lenox Hill Hospital in New York City, described the study’s finding as both “intriguing” and an “undoubtedly positive message to send to the public.”
“My first reaction to studies like this is that only in America do we have to prove to people that it’s good to walk,” he said with a chuckle.
“But it stands to reason that being active as we age is going to have a beneficial effect on the brain, just as being inactive is going to have a negative impact,” Pacia noted. “Because the brain lives in the environment of the body.”
But there may be a catch. “This is just an observational study,” Pacia noted. “And while we may assume that the relationship between the brain and activity is a prevention-of-atrophy issue — just like it is with muscle and bone — this study doesn’t actually prove that. We don’t yet know enough about the use-it-or-lose-it notion with respect to brain and exercise. So we do need more research to look at that.”
September 10, 2010
By: Kate Kelland
Daily tablets of large doses of B vitamins can halve the rate of brain shrinkage in elderly people with memory problems and may slow their progression toward dementia, data from a British trial showed on Wednesday,
Scientists from Oxford University said their two-year clinical trial was the largest to date into the effect of B vitamins on so-called “mild cognitive impairment” — a major risk factor for Alzheimer’s disease and other forms of dementia.
Experts commenting on the findings said they were important and called for larger, longer full-scale clinical trials to see if the safety and effectiveness of B vitamins in the prevention of neurodegenerative conditions could be confirmed.
“This is a very dramatic and striking result. It’s much more than we could have predicted,” said David Smith of Oxford’s department of pharmacology, who co-led the trial.
“It is our hope that this simple and safe treatment will delay development of Alzheimer’s in many people who suffer from mild memory problems.”
Mild cognitive impairment (MCI) affects around 16 percent of people aged over 70 worldwide and is characterized by slight problems with memory loss, language or other mental functions.
MCI does not usually interfere with daily life, but around 50 percent of people diagnosed with it go on to develop the far more severe Alzheimer’s disease within five years. Alzheimer’s is a mind-wasting disease for which there are few treatments and no cure, and which affects 26 million people around the world.
Smith and colleagues conducted a two-year trial with 168 volunteers with MCI who were given either a vitamin pill containing very high doses of folic acid, vitamin B6 and vitamin B12, or a placebo dummy pill.
These B vitamins are known to control levels of an amino acid called homocysteine in the blood, and high blood levels of homocysteine are linked to an increased risk of developing Alzheimer’s disease.
Helga Refsum, who also worked on the trial, stressed that vitamins were given in extremely high doses.
“This is a drug, not a vitamin intervention,” she said.
The pills, called “TrioBe Plus” contained around 300 times the recommended daily intake of B12, four times daily advised folate levels and 15 times the recommended amount of B6.
Brain scans were taken at the beginning and the end of the trial to monitor the rate of brain shrinkage, or atrophy.
The results, published in the Public Library of Science (PLoS) One journal, showed that on average the brains of those taking the vitamin treatment shrank at a rate of 0.76 percent a year, while those taking the dummy pill had an average brain shrinkage of 1.08 percent.
People who had the highest levels of homocysteine at the start of the trial benefited the most from the treatment, with their brains shrinking at half the rate of those on the placebo.
Although the trial was not designed to measure cognitive ability, the researchers found those people who had lowest rates of shrinkage had the highest scores in mental tests.
Commenting on the study, Paul Matthews, a professor of clinical neurology at Imperial College London said that although the vitamins used are generally safe and inexpensive, the study “should not drive an immediate change in clinical practice”
“Instead, it sets out important questions for further study and gives new confidence that effective treatments modifying the course of some dementias may be in sight,” he said.