High cholesterol is bad for your body - it's associated with increased risk of stroke and heart disease - but new research suggests that paradoxically, it could be good for your brain. Cholesterol is a fat-like substance found in the blood and most cells, especially in the brain.
Penelope Elias and colleagues at Boston University analysed data from 789 participants in the Framingham Heart Study. From 1948 to 1974-78, the participants received biennial medical check-ups, some of which included measures of their total serum cholesterol. Then once between 1974 to 1978, the participants completed a comprehensive battery of cognitive tests, including measures of their learning and memory ability, their attention and concentration, executive functioning and abstract reasoning.
Controlling for a plethora of variables, including age, education, occupation, blood pressure, and smoking, the researchers found that lower cholesterol was modestly, but significantly, associated with lower cognitive performance, especially on those subtests related to executive functioning (i.e. the ability to stay focused on the task at hand, or to switch successfully between different types of task).
"These effects have biological plausibility", the authors explained. "Low serum cholesterol and poorer cognitive functioning may be related because neuronal cells require cholesterol for normal metabolic processes".
However, the authors cautioned that cholesterol could simply be a biological marker for some other physiological or psychological factor that affects cognition.
Moreover, this current data was collected before anti-cholesterol drugs had become effective or widespread. "The result of lowering cholesterol with current medications may be very different from naturally low cholesterol", researcher Merrill Elias said. Readers on prescription medication to reduce their cholesterol should note therefore that the benefits to their cardiovascular health will almost certainly outweigh any potential detriment to their cognition.
Elias, P.K., Elias, M.F., D'Agostino, R.B., Sullivan, L.M. & Wolf, P.A. (2005). Serum cholesterol and cognitive performance in the Framingham Heart Study. Psychosomatic Medicine, 67, 24-30.
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.