Exercise reduces Alzheimer's damage in brain

August, 2012

A mouse study provides more support for the value of exercise in preventing Alzheimer’s disease, and shows one of the ways in which it does so.

A study designed to compare the relative benefits of exercise and diet control on Alzheimer’s pathology and cognitive performance has revealed that while both are beneficial, exercise is of greater benefit in reducing Alzheimer’s pathology and cognitive impairment.

The study involved mice genetically engineered with a mutation in the APP gene (a familial risk factor for Alzheimer’s), who were given either a standard diet or a high-fat diet (60% fat, 20% carbohydrate, 20% protein vs 10% fat, 70% carbohydrate, 20% protein) for 20 weeks (from 2-3 to 7-8 months of age). Some of the mice on the high-fat diet spent the second half of that 20 weeks in an environmentally enriched cage (more than twice as large as the standard cage, and supplied with a running wheel and other objects). Others on the high-fat diet were put back on a standard diet in the second 10 weeks. Yet another group were put on a standard diet and given an enriched cage in the second 10 weeks.

Unsurprisingly, those on the high-fat diet gained significantly more weight than those on the standard diet, and exercise reduced that gain — but not as much as diet control (i.e., returning to a standard diet) did. Interestingly, this was not the result of changes in food intake, which either stayed the same or slightly increased.

More importantly, exercise and diet control were roughly equal in reversing glucose intolerance, but exercise was more effective than diet control in ameliorating cognitive impairment. Similarly, while amyloid-beta pathology was significantly reduced in both exercise and diet-control conditions, exercise produced the greater reduction in amyloid-beta deposits and level of amyloid-beta oligomers.

It seems that diet control improves metabolic disorders induced by a high-fat diet — conditions such as obesity, hyperinsulinemia and hypercholesterolemia — which affects the production of amyloid-beta. However exercise is more effective in tackling brain pathology directly implicated in dementia and cognitive decline, because it strengthens the activity of an enzyme that decreases the level of amyloid-beta.

Interestingly, and somewhat surprisingly, the combination of exercise and diet control did not have a significantly better effect than exercise alone.

The finding adds to the growing pile of evidence for the value of exercise in maintaining a healthy brain in later life, and helps explain why. Of course, as I’ve discussed on several occasions, we already know other mechanisms by which exercise improves cognition, such as boosting neurogenesis.

Reference: 

Related News

Training in a mental imagery technique has been found to help multiple sclerosis patients in two memory domains often affected by the disease: autobiographical memory and episodic future thinking.

A study involving 218 participants aged 18-88 has looked at the effects of age on the brain activity of participants viewing an edited version of a 1961 Hitchcock TV episode (given that participants viewed the movie while in a MRI machine, the 25 minute episode was condensed to 8 minutes).

A study involving 100 healthy older adults (aged 60-80) has found that those with higher levels of physical activity showed more variable spontaneous brain activity in certain brain regions (including the

A ten-year study involving 2,092 older adults (average age 76) has found that people tended to lose awareness of memory problems two to three years before the onset of dementia.

A large, five-year study challenges the idea that omega-3 fatty acids can slow age-related cognitive decline.

A large, two-year study challenges the evidence that regular exercise helps prevent age-related cognitive decline.

A study involving 97 healthy older adults (65-89) has found that those with the “Alzheimer’s gene” (APOe4) who didn’t engage in much physical activity showed a decrease in hippocampal volume (3%) over 18 months.

An Indian study involving 648 dementia patients, of whom 391 were bilingual, has found that, overall, bilingual patients developed dementia 4.5 years later than the monolingual ones. There was no additional advantage to speaking more than two languages.

A study, involving 371 patients with mild cognitive impairment, has found that those with depressive symptoms had higher levels of amyloid-beta, particularly in the frontal cortex and the anterior and posterior

A study involving 206 spousal and adult children caregivers of dementia sufferers (mostly Alzheimer’s) has found that about 84% of caregivers reported a clinically significant burden. Three factors were significant contributors to the burden:

Pages

Subscribe to Latest newsSubscribe to Latest newsSubscribe to Latest health newsSubscribe to Latest news