It was found that the participants with a western dietary pattern, characterized by high intakes of takeaway food, red and processed meat, soft drink, fried and refined food, scored lower in cognitive tasks, particularly those involving reaction time/psychomotor function, visual attention, learning and memory.
Chips and crisps came in for a particular drubbing, as their high consumption was significantly associated with longer reaction times on detection tasks.
In contrast to their peers, study participants with a high intake of fruits and leafy vegetables had better cognitive performance, which according to lead researcher Dr Anett Nyaradi could be due to increased micronutrient content.
She added that several factors could be at play in the diet-related decline in cognitive skills, including the level of omega-6 fatty acids in fried foods and red meat.
High intake of saturated fat and simple carbohydrates has been linked to impairment in the functioning of the hippocampus, a brain structure centrally involved in learning and memory that increased its volume during adolescence, said Dr Nyaradi.