Effects of micronutrients supplementation on plasma homocysteine level and global cognitive function among older adults in long-term care facilities: a randomized controlled study

Objective To investigate the effects of micronutrient supplementation for the elderly on plasma homocysteine level and cognitive function in institutional older adults. Methods A total of 98 older adults with the score≤11 by mini nutritional assessment short-form aged 65-100 years were enrolled and assigned to either intervention group or control group (n=49 each), with either a package of micronutrient pack or placebo daily, for three months. Fasting blood samples were collected both at baseline and the end of study to detect serum vitamin B12, folate and plasma homocysteine (Hcy) concentrations. Global cognitive function was assessed using the mini-mental state examination (MMSE). The paired t test was used to compare the continuous variables between the two groups after intervention. The relationship between changes in MMSE score and changes in plasma Hcy concentrations was examined by least-squares linear regression. Results Eighty-two patients completed the study, and 17 patients withdrew from the study due to diarrhea and hospital discharge with the drop rate of 17.3%. Compared to the control group, concentrations of serum vitamin B12 (128.8±34.8 vs 13.3±16.0 pmol/L, P=0.003) and folate (21.1±1.6 vs 0.6±0.5 nmol/L, P<0.01) significantly increased in the intervention group over 3-month supplementation, while plasma Hcy levels were remarkably reduced (-5.3±0.7 vs 1.7±0.3 μmol/L, P<0.01). The incidences of deficiency of folate, deficiency of serum vitamin B12and high Hcy all decreased in intervention group. Although individual item scores in MMSE were not changed markedly, change of total MMSE score in intervention group were higher than that in the control group (1.2±3.0 vs -0.2±2.5, P<0.05). Conclusions The supplementation of the micronutrient pack in long-term care facilities can reduce the incidence of hyperhomocysteinemia, and improve the total MMSE score. Key words: Micronutrient; Older adults; Homocysteine; Cognitive function