The research, which looked at children between the ages of seven and 10, revealed a link between high-fat diets and poorer cognitive flexibility, as measured by a colour or shape selection task. Total fat consumption was linked to reduced accuracy, while saturated fat affected reaction times – and cholesterol impaired both accuracy and reaction times.
Mental ability impaired
“The current study provides novel evidence linking diet intake to cognitive flexibility among prepubertal children,” researchers wrote in the journal Appetite.
“The major findings were that fats, specifically saturated fats, were related to longer reaction time during the heterogeneous trials – the trial type requiring greater cognitive flexibility – and greater global switch cost for reaction time. Thus, increasing intake of saturated fats was associated with impaired ability to maintain multiple task sets in working memory as well as the selection of the subsequent task,” they added.
The study used data from 150 participants in the FITKids study at the University of Illinois at Urbana-Champaign. It correlated dietary information about participants’ food consumption in a single 24-hour period with their performance in a test to select the correct shape or colour under changing parameters.
Along with the link between high-fat diets and low cognitive flexibility, the study showed links between BMI and poorer accuracy. It also suggested aerobic fitness was linked to better accuracy levels.
Correlation, not causation
The paper’s authors note their research does not demonstrate a causal link between higher fat consumption and poor mental performance: “While it is assumed that variability in cognitive flexibility was driven by the diet measures, it is possible that the opposite may be true, such that lower cognitive flexibility may be implicated in poorer dietary choices.”
They also noted the study did not take micronutrient consumption into account, and that it relied only on one 24-hour recall to record food consumption. They suggested future studies could use multiple diet assessment techniques to reinforce the data used in their research, and called for greater focus on links between diet and cognitive performance.
“A broader implication of this study was that it provided evidence identifying cognitive flexibility as another core cognitive control process that may be susceptible to the detrimental effects of saturated fats and cholesterol intake,” the authors wrote.
“Cognitive flexibility is important because it comprises the ability to switch perspectives in daily life (e.g. viewing a problem from the point of view of others or from a different direction) and involves being flexible enough to adjust to changing demands or priorities.”
Published online ahead of print, doi: 10.1016/j.appet.2015.04.012
“The relation of saturated fats and dietary cholesterol to childhood cognitive flexibility”
Authors: N. A. Khan, L. B. Raine, E. S. Drollette, M. R. Scudder and C. H. Hillman