Monday, December 17, 2018

An important Large Study on Diet and Cognitive Improvement

Alzheimer's and Dementia, the Journal of the Alzheimer's Association, recently posted an article regarding a two-year study of diet intervention and its influence on cognition.  It was called the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER).  It studied a population of 1,260 at-risk patients over a period of two years.  (It wasn't clear to me how big the control population was vs. the study population.)  "At-risk patients" were 60 to 77 years of age and carried a higher risk of dementia based on a recognized risk scoring system.  

The study found that adherence to dietary guidelines predicted subsequent improvement in executive function among older adults, but not improved memory or processing speed.  The researchers suggested that longer periods of time or different diet approaches might produce results with respect actual improvement in memory and processing speed.  They said that cognitive improvement requires "intensive" dietary change.

The diet in the study followed Finnish national diet guidelines.  The guidelines were consistent with the Mediterranean and DASH diets we discuss in Beating the Dementia Monster.  The researchers acknowledged the MIND diet (also discussed in Beating the Dementia Monster), but they don't relate it to their study.  The study controlled for exercise, relaxation periods, social activity (including volunteer work), and other factors we discuss in Beating the Dementia Monster. 

While there have been a number of "longitudinal studies" correlating risk for developing neurodegenerative disease (like AD) with diet, the researchers say their "prospective study" is the first to correlate improved cognition with dietary interventions.  (But only the executive function component of cognition improved.)  A longitudinal study observes behaviors and resulting health consequences in a large population of subjects (e.g. the famous Framingham Heart Study), while a prospective study evaluates what happens as a consequence of purposefully changing behaviors (like diet).  A prospective study must compare results with the intervention population and a control population.

I had several takeaways from the report:
  • You can't eat your way to good brain health in two years.  It's good that you can improve executive function (and preserve your socially appropriate behavior), but memory and processing speed are just as important.
  • If you control diet studies for exercise their results are less impressive than you would hope.  We discuss this as well in Beating the Dementia Monster.  This underscores the importance of physical exercise if you want to do something about cognitive decline.
  • The researchers underlined that no dietary supplement has been shown to improve cognition.  They cited one optimistic review of the literature concerning a range of potential supplements and other interventions that nevertheless failed to find hope for any supplement.       


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