ScienceDaily (Feb. 13, 2012) — New research suggests that consuming between 2,100 and 6,000 calories per day may double the risk of memory loss, or mild cognitive impairment (MCI), among people age 70 and older.
The study was just released and will be presented at the American Academy of Neurology's 64th Annual Meeting in New Orleans April 21 to April 28, 2012. MCI is the stage between normal memory loss that comes with aging and early Alzheimer's disease.
"We observed a dose-response pattern which simply means; the higher the amount of calories consumed each day, the higher the risk of MCI," said study author Yonas E. Geda, MD, MSc, with the Mayo Clinic in Scottsdale, Arizona and a member of the American Academy of Neurology.
The study involved 1,233 people between the ages of 70 and 89 and free of dementia residing in Olmsted County, Minn. Of those, 163 had MCI. Participants reported the amount of calories they ate or drank in a food questionnaire and were divided into three equal groups based on their daily caloric consumption. One-third of the participants consumed between 600 and 1,526 calories per day, one-third between 1,526 and 2,143 and one-third consumed between 2,143 and 6,000 calories per day.
The odds of having MCI more than doubled for those in the highest calorie-consuming group compared to those in the lowest calorie-consuming group. The results were the same after adjusting for history of stroke, diabetes, amount of education, and other factors that can affect risk of memory loss. There was no significant difference in risk for the middle group.
"Cutting calories and eating foods that make up a healthy diet may be a simpler way to prevent memory loss as we age," said Geda.
The co-authors of the study include Ronald C. Petersen, MD, Fellow of the American Academy of Neurology, and other investigators of the Mayo Clinic Study of Aging in Rochester, Minn.
The study was supported by the National Institutes of Health, the Robert Wood Johnson Foundation and the Robert H. and Clarice Smith and Abigail van Buren Alzheimer's Disease Research Program.
Wednesday, February 15, 2012
Good Aerobic Capacity Promotes Learning
Aerobic fitness has a favorable effect on cognitive functions. For example, physically active elderly people are less prone to aging-related cognitive decline than those who lead a sedentary lifestyle. An increase in physical activity raises both aerobic capacity and learning ability in both humans and animals. However, it is not known whether it is the aerobic capacity or the pleasure and enrichment of physical activity that promotes cognitive functions.
A study conducted by research groups at the University of Jyväskylä shows that aerobic fitness -- not physical activity as such -- promotes cognitive abilities.
- In this study, we used rat strains raised at the University of Michigan. They had been selectively bred over 23 generations for their endurance running capacity. Due to this breeding, there were natural-born long-distance runners and very poor runners. Results from a test that is a counterpart to the human maximal endurance test indicate that the difference between these strains was 500%, says Heikki Kainulainen, Professor of Exercise Physiology.
- Rats were trained in a discrimination learning test that measures flexible cognition. They were first taught to fetch a food reward in the presence of one tone and to ignore the other one. After learning this rule, the stimulus assignment was reversed and they were required to abandon the old rule and learn a new one, describes Dr. Jan Wikgren, Senior Researcher at the Department of Psychology.
It was found that rats with intrinsically high aerobic capacity clearly outperformed those with intrinsically low aerobic capacity. It must be emphasized that the animals were not given any physical exercise before the learning test. Thus, the results suggest that it is the aerobic capacity and not physical activity alone that is related to flexible cognition.
The results gave rise to many questions. Probably the most crucial seeks to determine the neurobiological mechanisms that mediate the effect of aerobic capacity on brain function.
- In future experiments we aim at studying the possible differences between these strains from the molecular to neurophysiological levels of analysis. Ultimately, we hope to investigate plausible exercise interventions that protect the brain from the detrimental effects of aging, Wikgren and Kainulainen explain. At least it is safe to say that physical activity is good for your brain at any age.
A study conducted by research groups at the University of Jyväskylä shows that aerobic fitness -- not physical activity as such -- promotes cognitive abilities.
- In this study, we used rat strains raised at the University of Michigan. They had been selectively bred over 23 generations for their endurance running capacity. Due to this breeding, there were natural-born long-distance runners and very poor runners. Results from a test that is a counterpart to the human maximal endurance test indicate that the difference between these strains was 500%, says Heikki Kainulainen, Professor of Exercise Physiology.
- Rats were trained in a discrimination learning test that measures flexible cognition. They were first taught to fetch a food reward in the presence of one tone and to ignore the other one. After learning this rule, the stimulus assignment was reversed and they were required to abandon the old rule and learn a new one, describes Dr. Jan Wikgren, Senior Researcher at the Department of Psychology.
It was found that rats with intrinsically high aerobic capacity clearly outperformed those with intrinsically low aerobic capacity. It must be emphasized that the animals were not given any physical exercise before the learning test. Thus, the results suggest that it is the aerobic capacity and not physical activity alone that is related to flexible cognition.
The results gave rise to many questions. Probably the most crucial seeks to determine the neurobiological mechanisms that mediate the effect of aerobic capacity on brain function.
- In future experiments we aim at studying the possible differences between these strains from the molecular to neurophysiological levels of analysis. Ultimately, we hope to investigate plausible exercise interventions that protect the brain from the detrimental effects of aging, Wikgren and Kainulainen explain. At least it is safe to say that physical activity is good for your brain at any age.
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