How to reduce your risk of dementia and Alzheimer’s

We've written multiple columns and Health and Nutrition Bite articles on the link between poor diet and the risk of dementia or Alzheimer's Disease. A good overview is in our "How the Standard American Diet (SAD) affects the brain" article from 2016, and the following year we followed that article up with a summary of a talk given by Timothy Harlan, MD, entitled "4 ways to protect your brain with diet" that he gave to a psychiatric medicine conference.

Both articles indirectly suggest that a Mediterranean-style diet has a role to play in protecting the brain from cognitive decline, whether the more common age-related dementia, or Alzheimer's Disease.

Recently a team of researchers in Spain were able to publish research describing the results of a prospective study of over 16,000 men and women that tracked participants for over 21 years (Nutrients 2021;13:700).

The research made use of data gathered for a study known as the European Prospective Investigation into Cancer and Nutrition (EPIC)-Spain Dementia Cohort Study. The participants were recruited between the ages of 30 and 70 between 1992 and 1996. They attended in-person interviews with professionals to assess diet, lifestyle, and medical and reproductive history, then underwent a physical exam to measure height, weight, and waist circumference.

From the dietary interview the researchers were able to evaluate each participant's usual diet, assigning each participant's diet a modified Mediterranean Diet score. Instead of a 1-9 point score, the authors expanded the scoring to include levels of intake for each point: instead of scoring 1 for consuming the minimum of, say, fruits and nuts, the authors assessed the relative intake of fruits and nuts across the entire cohort and awarded a score of 2 for those in the highest third of intake, a 1 for those in the middle third of intake, and 0 (zero) for those in the lowest third of intake.

Thus instead of a high score being considered 6-9 points, a High score in this modified Mediterranean Diet score is 11-18. A Medium score is 7-10 points, and a Low score is from 0 to 6 points.

Through access to the national medical record, the authors were able to identify those participants who were diagnosed with dementia (non-Alzheimer's type) or dementia of the Alzheimer's type.

The researchers found that compared to those with a Low modified Mediterranean Diet score, those with a High score were 20% less likely to be diagnosed with some type of dementia. The effects were greater for men, with a 31% lower risk of dementia for those with a High modified Mediterranean Diet score as opposed to 13% lower risk for women.

Upon further examination, the authors noted that for both men and women, every two-point increase in the modified Mediterranean Diet score meant an 8% lower risk of developing dementia.

When the researchers differentiated between dementia of the Alzheimer's type and dementia of the non-Alzheimer's type, they found that the association with higher modified Mediterranean Diet score was stronger between women and non-Alzheimer's type dementia - and between men and Alzheimer's type dementia.

What this means for you

This long-term, large scale study just adds to the evidence that a Mediterranean-style diet protects the brain from dementia. Take the Mediterranean Diet score quiz to assess your score and get tips for improving your score.

First posted: June 9, 2021