Homocysteine, vitamin B12 and folic acid plasma levels in relation to cognitive functions in an Egyptian elderly group

Abstract

Several studies suggested that elevated plasma total homocysteine (tHcy) concentrations are associated with cognitive impairment and dementia. High plasma homocysteine concentrations can be largely attributed to inadequate status of folic acid and vitamin B12. On the other hand, data from several studies indicate that plasma homocysteine increases with age, independent of vitamin status. We investigated the relation between plasma tHcy, vitamin B12 and folic acid levels and cognitive functions in an elderly Egyptian group. We also studied the effect of vitamin B12 and folic acid supplementation on plasma tHcy and cognitive functions. About 56 subjects (30 males and 26 females) similar in socio-economic class (upper-middle), with an age range of 60-70 years completed the study course. All were healthy working professionals. Clinical, nutritional and anthropometric evaluations were performed. Cognitive function evaluation using the Kendrick Battery for detecting dementia was applied. Biochemical analysis for blood homocysteine, vitamin B12 and folic acid was performed. All evaluations were performed at the beginning of the study and after four months of supplementation with biscuits rich in vitamin B12 and folic acid. The results of the study show that there is a significant correlation between plasma tHcy and cognitive functions, both object learning test (OLT) (short-term memory) and digit copying test (DCT) (attention focus) both before p (<0.01) and after p (<0.01) vitamin supplementation and also between vitamin B12 and cognitive functions before and after supplementation p (<0.05). Significant decrease in plasma tHcy and increase in vitamin B12 and folic acid level is recorded after supplementation p (<0.01). There is a significant improvement in cognitive functions, both OLT and DCT after vitamin supplementation p (<0.05). In conclusion, elevated plasma tHcy level and low vitamin B12 levels are positively correlated to impairment in cognitive functions. Vitamin B12 and folic acid supplementation decreased plasma tHcy level and improved cognitive functions. We recommend vitamin B12 and folic acid supplementation for elderly.