Serum cholesterol and intellectual performance

The current investigation sought to determine whether intellectual performance is related to serum lipid concentrations.

Subjects were 177 healthy, Caucasian adult males and females, aged 25 to 60 years, with widely varying total cholesterol concentrations. Crystallized intelligence was estimated from the Information and Vocabulary subtests of the Wechsler Adult Intelligence Scale, Revised (WAIS-R). Fluid intelligence was estimated from the WAIS-R Block Design subtest, and from a computerized version of the Letter Rotation test.

Controlling for age, better performance on both Information and Vocabulary subtests was associated with lower total and low-density lipoprotein (LDL) cholesterol and triglyceride concentrations (r's = -.24 to -.35, p's < .005). In contrast, better performance on Block Design was correlated with higher total and LDL cholesterol (r's = .22 to .23, p's < .005). Letter rotation response latency was unrelated to serum lipids.

These opposing relationships between serum cholesterol and different dimensions of intellectual performance, on the one hand, may reflect the propensity of knowledgeable individuals to consume low fat diets, and on the other hand, suggest that serum cholesterol concentration may be a correlate of brain nutrients important to mental efficiency.