Dietary Fat Intake and Cognitive Function Among Young and Middle-Aged Adults: The Third National Health and Nutrition Examination Survey

Primary Objective: The objective was to examine whether dietary intakes of macronutrients are associated with neuropsychological performance.

Research Design and Method: Study participants were 3960 adults aged 20–59 years, who completed three neuropsychological tests and a 24-hour dietary recall as a part of the Third National Health and Nutrition Examination Survey, 1988–1994. Poor performance was defined as the test score below gender-specific 15th percentile.

Main Outcomes and Results: While holding the energy percentages from different macronutrients, additional 100 kcal intake of energy was associated with a reduced odds of poor performance on serial digital learning test (OR = 0.98, 95%CI = 0.96, 0.99) and symbol digital substitution test (OR = 0.97, 95%CI = 0.96, 0.99). Compared with equivalent energy from carbohydrates, each 5% of energy from poly-unsaturated fatty acids (PUFA) or total fat was associated with a reduced OR of poor performance on simple reaction time test (PUFA: OR = 0.77, 95%CI = 0.63–0.95 and total fat: OR = 0.93, 95%CI = 0.87, 0.99). Poor global cognition was associated with an additional intake of 100mg cholesterol (OR = 1.14, 95%CI = 1.05, 1.23). These associations were more salient in men.

Conclusion: Habitual intake of macronutrients is weakly but significantly associated with cognitive functioning. These relationships are more evident in men.