Sunday, March 22, 2009

Caloric Restriction Improves Memory in the Elderly

Eating less may help with delaying Alzheimer's disease
Eating less may help with delaying Alzheimer's disease. (Photo by patrickeaster)

The good news for caloric restriction just keeps coming. While optimal anti-aging benefits may require starting caloric restriction during early adulthood, good things will apparently come to those who cut their calorie intake after middle age too.

One of those things seems to be an improvement in maintaining brain function. That's very exciting, because memory impairment is an indication of Alzheimer's disease, which is a big problem among the aging population. In their study, Witte et al. compared the effects of calorie restriction (CR) and increased unsaturated fatty acid (UFA) intake on memory in the elderly. They found that eating less was more effective in improving memory scores than eating more unsaturated fatty acids.

Study participants and methods

The participants were 50 healthy, normal- to overweight elderly men and women, with a mean age of 60.5 years. They were divided into three groups: the calorie-restricted group, the unsaturated fatty acid group, and the control group.

The CR group was instructed to eat 30% less than their normal energy intake. Minimal intake was set to 1,200 kcal per day to avoid malnutrition. The UFA group was told to increase their unsaturated fatty intake by 20% but keep total fat intake unchanged (i.e. they also reduced their saturated fat intake by 20%). The participants in the control group were instructed to follow their usual diets. The experiment lasted for 3 months.

Neuropsychological testing was done using the Rey Auditori Verbal Learning Task, which measures the ability to memorize words. The participants were asked to learn as many words as possible from a list of 15 words and then correctly recall them after 30 minutes.

Results

The participants reported on a postintervention questionnaire that they followed the dietary guidelines successfully. The CR group reduced their calories and lost weight, whereas the UFA and control groups tended to gain weight. The ratio of unsaturated-to-saturated fat intake more than doubled in the UFA group, with most of the new unsaturated fats being polyunsaturated.


Calorie restriction vs. unsaturated fat intake: effect on memory

The figure above shows that only the CR group significantly increased their memory scores, showing an improvement of 30%. The UFA and control group did not show a significant change in their ability to recall words correctly. The authors speculate that the lack of improvement in the UFA group might have been due to the participants consuming very little marine sources of omega-3 unsaturated fatty acids, which have been suggested to improve brain function.

Conclusion

Healthy, elderly subjects (normal to overweight) on a calorie restriction diet showed a 30% increase in memory scores compared to a control group. Replacing saturated fats with polyunsaturated fats did not result in similar changes.

For more information on caloric restriction, see these posts:

Anti-Aging in the Media: National Post on Caloric Restriction
Moderate and Severe Caloric Restriction Alter Behavior Differently in Rats
Anti-Aging in the Media: Houston Press on Caloric Restriction
A Week of Caloric Restriction - Experiment Begins



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3 kommenttia:

Johann January 21, 2011 at 8:58 AM  

As mentioned in your post, unsaturated fats weren't largely from marine sources. I don't see any potential benefit substituting saturated fats with omega-6 rich plant oils. Before I start restricting my calories I would like to see a study which shows that this is more beneficial than supplementing pharmaceutical grade fish oil or just restricting your carbs.

Johann January 21, 2011 at 9:00 AM  

As mentioned in your post, unsaturated fats weren't largely from marine sources. I don't see any potential benefit substituting saturated fats with omega-6 rich plant oils. Before I start restricting my calories I would like to see a study which shows that this is more beneficial than supplementing pharmaceutical grade fish oil or just restricting your carbs.

Keith February 12, 2014 at 4:36 PM  

I wonder what the results would be if a group were to be placed on an unrestricted calorie-intake no-carb regimen, similar to the Stefansson/Andersen year-long meat and fat experiment.

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