Relationship between Decline in Cognitive Function and Homocysteine, Folate, and Vitamin B12

Abstract

Hyperhomocysteinemia (HHcy) causes various diseases, including cardiovascular disease, osteoporotic fractures and dementia. Although there have been reports that HHcy impairs cognitive function, findings are inconsistent on the association of homocysteine (Hcy), folate, and vitamin B12 with cognitive function. Considering that a lower-quality diet increases the risk of dementia in elderly individuals, the effect of nutritional status must be clarified. In the present study, a case‒control study and an intervention study were conducted. In Study 1, 85 patients who visited the clinic with complaints of memory impairment were evaluated for their plasma Hcy, serum folate, serum vitamin B12 concentrations and cognitive function. Although not statistically significant, plasma Hcy concentrations in dementia patients (11.00 ± 4.90 nmol/mL) as well as MCI patients (10.7 ± 2.49 nmol/mL) were higher than those in the normal cognitive-function group (9.74 ± 3.84 nmol/mL). In Study 2, 42 patients with HHcy at the first visit were administered Memorin®, a dietary supplement containing vitamin B12, folate, vitamin B6, and other ingredients, for 10 months. HHcy (12.3 ± 4.58 nmol/ mL) was significantly improved 4 months (10.0 ± 3.85 nmol/mL) and 10 months (10.16 ± 3.12 nmol/mL) after the administration of Memorin®. The pharmacological actions of dietary supplements for HHcy were discussed in this article.