Protecting our Brain: Recent Research

Brain Volume and Mental Function

With age, the brain tends to atrophy and shrink in volume. For those over 70, 16% experience mild cognitive impairment (MCI), characterized by issues with memory, language and other mental functions. And over ½ of those with MCI progress to Alzheimer’s.

Two new studies suggest that there may be steps we can take to help protect our mental abilities like thinking, reasoning and remembering – all part of what’s termed cognitive function.

Walking To Help Preserve Mental Function

Findings from a University of Pittsburgh study provide more evidence that physical activity can play a key role in protecting our brain as we grow older (1).

The investigators did additional research on nearly 300 of the 1,400+ people who are part of the long term Cardiovascular Health Study. The participants, who were all cognitively normal at the beginning of the study, underwent MRI brain scans 9 years later. After 13 years, they were tested for MCI or dementia.

Based on weekly walking distances, participants were divided into four groups. The average number of blocks walked per week was 8, 21, 45 and 156 in the groups. After the brain scan, only those in the group with the highest amount of walking showed significantly greater volumes in three gray matter areas of the brain.

At the 13 year mark, about 39% of the participants had developed some degree of MCI while the rest still had normal cognition. The researchers found that the larger gray matter volume observed with physical activity reduced the risk of cognitive impairment 2-fold. This study was conducted in people with an average age of 78 – a time of life when the risk for brain deterioration and dementia are greatest. So, it’s tempting to think that starting a walking program even earlier in life may be a good way to help preserve our brain as it ages. For certain, physical activity will benefit the heart, help keep weight down, and reduce the risk of getting a number of chronic diseases.

Extra B-Vitamins May Slow Dementia

Though not all studies examining the effects of B-vitamins in cognitive impairment have reported benefit, recent findings (2) from Oxford University’s Project to Investigate Memory and Aging are heartening. They suggest that supplemental B-vitamins can slow the progress of dementia.

The trial enrolled individuals over 70 with MCI who were given 3 B-vitamins (folic acid, vitamins B6 and B12) or placebo. Of the 271 participants, 168 had MRI brain scans at the start and end of the two-year study.

The brain scans showed that the B-vitamin group had a significantly slower rate of brain atrophy and shrinkage over time compared to placebo. The researchers also reported that at the end of the trial, a greater rate of brain deterioration was linked with lower test scores measuring cognitive function.

The B-vitamins lowered levels of homocysteine – the artery damaging compound once thought to raise the risk of heart disease and stroke. There is evidence, though, that homocysteine is a likely culprit in dementia and some eye diseases like AMD and glaucoma. In this study, among those with the highest homocysteine levels at the study’s start, taking B-vitamins reduced the rate of brain shrinkage by ½ compared to taking placebo.

Accelerated brain atrophy is often seen in people with MCI who go on to get Alzheimer’s. More studies will be needed to see whether B-vitamins can delay the progression of MCI to Alzheimer’s disease.

References

1. Erickson KI, et al. Physical activity predicts gray matter volume in late adulthood: the Cardiovascular Health Study. Neurology 75:1415-22, 2010.
2. Smith AD, et al. Homocysteine-lowering by B vitamins slows the rate of accelerated brain atrophy in mild cognitive impairment: a randomized controlled trial. PLoS One 5:e12244, 2010.