Regular vitamin B12 supplementation among older Chinese men in a veterans care home in Taiwan

Vitamin B12 deficiency is common in older adults, and may be associated with cognitive impairment and depression. The main purpose of this study is to explore clinical effectiveness of regular vitamin B12 supplementation on cognitive function and depressive symptoms among oldest old men living in a Taiwanese veterans care home. All residents of Banchiao Veterans Care Home were invited for study. Status of regular vitamin B12 supplementation was determined. Cognitive function and depressive symptoms were evaluated by mini-mental state examination (MMSE) and geriatric depression scale (GDS). Subjects with renal insufficiency or established diagnosis of vitamin B12 deficiency were excluded. Comparisons of demographic data, MMSE, GDS, and serum vitamin B12 between subjects with and without regular supplementation were done. In total, 419 residents (mean age = 80.8 ± 5.5 years, all males) were enrolled. The mean serum level of vitamin B12 was 1294.1 ± 189.1 pg/ml (range: 50–30,000 pg/ml). Forty-five subjects (10.7%) reported regular vitamin B12 supplementation, and their mean serum levels of vitamin B12 were significantly higher than the non-supplementation subjects (8057.4 ± 1408.3 pg/ml vs. 480.4 ± 14.5 pg/ml, p < 0.001). The mean MMSE (26.7 ± 4.6 vs. 26.7 ± 3.7, p = 0.965), GDS (1.8 ± 1.7 vs. 1.9 ± 2.3, p = 0.595), prevalence of cognitive impairment (13.6% vs. 19.3%, p = 0.420) and depressive symptoms (4.5% vs. 8.4%, p = 0.375) were similar between subjects with and without regular vitamin B12 supplementation. In conclusion, regular vitamin B12 supplementation and high serum level of vitamin B12 are not associated with better cognitive function or depressive symptoms among asymptomatic oldest old men in a Taiwanese veterans care home.