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.

A pilot study on hyperinsulinaemic euglycaemic clamp based insulin sensitivity in young adult Indian males with low body mass index.

Background & objectives: Indians have decreased insulin sensitivity (IS) and a greater adiposity at a lower body mass index (BMI) when compared with other ethnic groups. Despite this, IS has not been studied in Indians of low BMI. This study thus used the hyperinsulinaemic euglycaemic clamp (HEC) technique to compare IS in young normal weight (NW) and low BMI (LBMI) Indian males. Clamp IS was also compared with convenient indices of insulin sensitivity such as the homeostatic model assessment (HOMA). In the NW group, clamp IS was compared with published data of similarly measured IS in other studies and ethnic groups. Methods: Ten NW [body mass index (BMI): 18.5-25 kg/m2] and ten LBMI (BMI < 18.5 kg/m2) young healthy Indian males aged between 19-32 yr were recruited through advertisements from Bangalore slums. Fasting plasma glucose and insulin, glucose disposal rates (GDR) and IS were the parameters measured during the HEC technique. Results: The NW group had a Clamp IS of 4.5 (3.8, 5.3) (median, lower, upper quartile, mg/(kg. min)/μU/ml) that was close to half that of the LBMI group; 9.9 (7.1, 13.4: P<0.001). Clamp IS in the NW group was significantly lower than that observed in published studies involving other ethnic groups (P<0.05). Clamp IS and per cent body fat (% BF), were significantly and negatively correlated (n=20, ρ = -0.7, P<0.001). Correlations between Clamp IS and other IS indices ranged from ρ = -0.5 for HOMA2-%B to ρ = 0.5 for HOMA2-%S (P<0.05); however, the correlation with HOMA1-IR was not significant (ρ = 0.4). Interpretation & conclusions: The significantly lower Clamp IS of the NW group compared with the LBMI group and other ethnic groups indicated that IS was impaired in Indians at relatively low BMIs. Most of the convenient indices of IS were significantly correlated with Clamp IS, however, the Clamp IS was more sensitive method with greater discriminatory power, since IS differences between LBMI and NW groups were only apparent with Clamp IS.