Vitamin B12 deficiency & levels of metabolites in an apparently normal urban south Indian elderly population

BACKGROUND & OBJECTIVES There is no published literature on the extent of vitamin B₁₂ deficiency in elderly Indians as determined by plasma vitamin B₁₂ levels and methylmalonic acid (MMA) levels. Vitamin B₁₂ deficiency is expected to be higher in elderly Indians due to vegetarianism, varied socio-economic strata and high prevalence of Helicobacter pylori infection. We therefore, studied the dietary habits of south Indian urban elderly population and measured vitamin B₁₂, MMA red cell folate and homocysteine (Hcy) levels. METHODS Healthy elderly urban subjects (175, >60 yr) were recruited. Detailed history, physical examination and neurological assessment were carried out. Food Frequency Questionnaire (FFQ) for dietary analysis for daily intake of calories, vitamin B₁₂, folate and detailed psychological assessment for cognitive functions was carried out. Blood samples were analyzed for routine haematology and biochemistry, vitamin B₁₂, red cell folate, MMA and Hcy. RESULTS The mean age of the study population was 66.3 yr. Median values for daily dietary intake of vitamin B₁₂ and folate were 2.4 and 349.2 μg/day respectively. Sixty two (35%) participants consumed multivitamin supplements. Plasma vitamin B₁₂ level and the dietary intake of vitamin B₁₂ was significantly correlated (P=0.157). Plasma vitamin B₁₂ and Hcy were inversely correlated (P= -0.509). Red cell folate was inversely correlated with Hcy (P= -0.550). Significant negative correlation was observed between plasma vitamin B₁₂ and MMA in the entire study population (P= -0.220). Subjects consuming vitamin supplements (n=62) had significantly higher plasma vitamin B₁₂ levels, lower MMA levels and lower Hcy levels. There was no significant correlation between plasma vitamin B₁₂, MMA, Hcy and red cell folate and any of the 10 cognitive tests including Hindi Mental Status Examination (HMSE). INTERPRETATION & CONCLUSIONS Our study is indicative of higher vitamin B₁₂ (2.4 μg/day) intakes in urban south Indian population. Thirty five per cent of the study population consumed multivitamin supplements and therefore, low plasma vitamin B₁₂ levels were seen only in 16 per cent of the study subjects. However, MMA was elevated in 55 per cent and Hcy in 13 per cent of the subjects.