Cognitive Decline and the Mediterranean Diet

I have previous posted on some of the research related to beneficial effects of a Mediterranean style diet on health.  In one post I summarized some of the quantities of food types in those judged to have a high rating for the diet.

A recent study by Tangney and colleagues looked at the rate of cognitive decline in a prospective study of elderly adults in Chicago, Illinois.  The study retrospectively judged the diet of participants for characteristics consistent with a Mediterranean diet.  The exact scoring sheet is not included in the manuscript but based on the data provided and other resources, I have attempted to summarize the rating in the spreadsheet below.

Before looking at the rating system, the study results of note include:

• Subjects were rated on compliance with the Mediterranean Diet and another diet rating for compliance with the USDA food pyramid model
• White subjects scored higher on compliance with the Mediterranean diet while black subjects scored higher on the USDA food pyramid model
• Higher scores on the Mediterranean diet were correlated with a slower rate of cognitive decline over time (cognitive decline was judged based on a composite score of a memory test, the Minimental Status Exam and a digit symbol substitution test)

Looking in more detail at this current study, the highest tertile (highest third) in the Mediterranean diet scored 30-45 on the Mediterranean average weekly diet score. (There was some score adjustment for total calorie intake it the study).  The rating includes 11 categories rated from 0-5 on each item for a maximum of 55 points.  The study looked at two different ratings for alcohol intake.  One looked only at alcohol intake and one looked at total alcohol intake. (Use only one of the two rating for item 11, not both).  Both low and high consumption of alcohol is rated lower on the scale than a consumption of 1-2 drinks per day.  Interestingly, a slower rate of cognitive decline was found in the present study when either red wine or total alcohol was used.

The amount of weekly servings for cereals/whole grains and vegetables looks a little overwhelming.  But four slices of whole grain bread per day by itself would put you in the 4 rated for cereals/pasta/whole grains.  You really only need a top score of 5 in 6 categories to reach what was found as the top third in a U.S. sample.  If you throw in a couple of days per week without red meat you can reach a 3 in the red meat category (I hate to make this recommendation since my father raised cattle in Nebraska). 


So looking at the scoring system used in this study helps put the diet in better perspective.  Many people are probably scoring mid-range on the Mediterranean diet but with a few adjustments could significant improve their compliance with the diet.


Photo of WGC Accenture winner Luke Donald at 2010 PGA Championship courtesy of Yates Photography. 


Spreadsheet summary scale adapted from manuscript by author.


Tangney CC, Kwasny MJ, Li H, Wilson RS, Evans DA, & Morris MC (2011). Adherence to a Mediterranean-type dietary pattern and cognitive decline in a community population. The American journal of clinical nutrition, 93 (3), 601-7 PMID: 21177796