Saturday, January 31, 2015

Mediterranean Diet and Aging

Bill Yates
Brain Posts
Jan 19 / 2015

There is a growing research body of evidence to support beneficial effects of a Mediterranean diet on brain health.

In previous posts I have reviewed research on the Mediterranean diet and:

Cognitive Decline

Alzheimer's Disease Prevention

A recent study adds an important element in potential mechanisms for the beneficial effects of the Mediterranean diet.

Marta Crous-Bou and colleauges from Harvard University and the University of Washington published a study of the Mediterranean diet and chromosome telomere length.

This analysis used the large Nurses' Health Study cohort, blood samples and dietary questionnaires. Blood samples were analyzed for chromosome telomere length.

Chromosome telomere length has emerged as a biomarker of aging. DNA chromosome telomere lengths decline with age and shortened telomere lengths are associated with shortened life expectancy. 

The natural process of telomere shortening appears accelerated by inflammation and may be modified by lifestyle behaviors including dietary composition.

In the current study, subjects regularly completed dietary questionnaires. These questionnaires were rated on compliance with the Mediterranean diet on nine variables:
  1. Vegetables
  2. Fruits
  3. Nuts
  4. Whole grains
  5. Legumes
  6. Fish
  7. Monounsaturated fat to saturated fat ratio
  8. Red meat consumption
  9. Alcohol intake
Median values for variables 1-8 were identified and subjects received a score of 1 if they were above the median (below median for red meat consumption). One point was awarded for consuming between 5 and 15 grams of alcohol per day.

Telomere length shortening was associated with older age and heavier cigarette consumption history.

Subjects were grouped into quintiles (20%) groups from lowest to highest Mediterranean diet score.

After adjusting for confounding variables, telomere length was statistically linked to Mediterranean diet score. Those with higher ratings on Mediterranean diet had longer telomeres indicating better aging.

The highest quintile group reported the following mean daily servings for each category: Vegetables (4.3 servings per day), fruits (3.2), whole grains (2.1), fish (0.5), red meat (0.5), legumes (0.6) and nuts (0.5).

The authors note they were unable to identify any single variable that had a strong independent effect. The effect appeared to be a combined global effect of the Mediterranean diet score.

This is an important study because it adds evidence for a biological mechanism for some of the previously reported clinical advantages associated with a Mediterranean diet.

However, this study is limited by being primarily cross-sectional in design. It does not inform on whether changing diet to a Mediterranean type reduces rate of telomere shortening. 

Readers with more interest in this research can access the free full-text manuscript by clicking on the citation link below.

Photo of foods highlighted in the Mediterranean diet is an original photo from my files.

Follow me on Twitter WRY999.

Crous-Bou M, Fung TT, Prescott J, Julin B, Du M, Sun Q, Rexrode KM, Hu FB, & De Vivo I (2014). Mediterranean diet and telomere length in Nurses' Health Study: population based cohort study. BMJ (Clinical research ed.), 349 PMID: 25467028

See the original article:

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