Short-term influence of elevation of plasma homocysteine levels on cognitive function in young healthy adults

Background: Acute homocysteine elevation has been shown to have a significant impact on cognitive function in animal models. Objectives: Investigation of the short-term impact of elevation of plasma homocysteine levels through a dietary intervention on cognitive abilities of young healthy adults. Participants: 100 healthy medical students of both genders were enrolled in the study. Design and Measurements: Homocysteine levels and cognitive abilities were measured at 08:30 (before breakfast) and at 15:00 (two hours after lunch and six hours after breakfast). Food intake was restricted to specified comestibles. The cognitive assessment comprised a version of the Short Test for General Intelligence, three subtests of the Syndrome Short Test and the Stroop test. Results: At 15:00 plasma homocysteine was significantly elevated in 56 participants (P<0.00001), whilst in 44 it was decreased (P<0.00001) in comparison to baseline (08:30). The decrease was however of limited clinical significance. The differences in the changes in cognitive performance between the two groups did not attain statistical significance (P>0.05) and the direction of the changes did not differ between them. Accordingly, the multiple linear regression analysis did not reveal an important influence of homocysteine elevation on cognitive performance variations. Conclusions: Significant increase of plasma homocysteine is not associated with a straightforward inhibitory or facilitatory short-term effect on physiological cognitive parameters in young healthy adults.