Latest scientific news 30 April 2019

Do dietary patterns influence cognitive performance in midlife?

What is good for the heart is also good for the brain. Prospective studies show that elder individuals have fewer cardiovascular diseases and a lower risk of dementia when consuming a Mediterranean diet with moderate wine consumption. But which role does nutrition play in early adulthood with respect to the cognitive performance*? The objective of the current CARDIA (Coronary Artery Risk Developmment in Young Adults) study was to investigate this question.

WHAT IS IT?

During a period of 30 years, the association between three heart-healthy dietary patterns and cognitive performance in midlife was examined. The three dietary patterns are: Mediterranean diet (MedDiet), Dietary Approches to stop Hypertension (DASH), A Priori Diet Quality Score (APDQS).

At the beginning of the study, the 2600 healthy participants were 25 years old.

Their eating patterns were assessed at three stages:

  • at the start of the study,
  • after 7 years, and
  • after 20 years.

The cognitive functions were evaluated after 25 and 30 years with validated neurological tests.

WHAT DOES IT SHOW?

The mechanisms by which diet can influence midlife cognitive performance are not clear but likely to involve oxidative stress, inflammatory and vascular disease pathways that contribute to an accelerated cognitive decline and dementia. On the other hand, the findings suggest that a longer adherence to the MedDiet (and APDQS) was associated with less decline in general cognitive function at midlife.

  • Antioxidants from foods (fruits, vegetables, legumes, nuts) and beverages (red wine) protect against oxidative damage and can influence inflammatory processes.
  • Anti-oxidant rich diets, particularly the MedDiet are known to reduce oxidative stress.
  • Dietary components (ie. polyphenols in wine, fruits and vegetables) have anti-inflammatory properties.

Furthermore, the authors explain that moderate intake of alcoholic beverages is not considered in the DASH dietary score suggesting that moderate alcohol intake as part of a healthy diet could be relevant for brain health in midlife.

WHAT DOES IT MEAN?

The role of alcohol in brain health is not clear but moderate intake of alcoholic beverages may exert protective effects on cognitive function via decreased platelet aggregation or modification of blood lipids, thus decreasing the vascular risk. In particular, a moderate wine consumption can exert anti-oxidative and anti-inflammatory effects which contributes not only to decrease the cardiovascular risk factors but also preserves the cognitive functioning.

This study confirms how important it is to consider moderate wine consumption as part of a healthy eating pattern and not as a single component.

McEvoy CT, Hoang T, Sidney S, Steffen LM, Jacobs DR, Shikany JM, Wilkins JT, Yaffe K, Dietary patterns during adulthood and cognitive performance in midlife – The CARDIA study, Neurology 2019;92:e1589-e1599; www.doi:10.1212/WNL.0000000000007243

For more information about this article, read the scientific abstract here.

(*) Cognitive function was assessed using 3 standardized tests:

  1. Rey Auditory Verbal Learning Test (RAVLT) to assess verbal learning and memory; the number of words correctly recalled after a 10-minute delay was used in the current analyses (range 0–15), with higher scores indicating better performance;
  2. Digit Symbol Substitution Test (DSST) to assess processing speed and executive function (range 0–133), with higher scores for digits correctly substituted indicating better performance; and
  3. Stroop test to assess executive function. The Stroop Interference score was obtained by subtracting the score on subtest 2 from the score on subtest 3, with lower scores indicating better performance. A composite cognitive function score was computed by transforming each of the 3 tests to standardized z scores and averaging the summed total.