[show abstract][hide abstract] ABSTRACT: Vitamin B(12) (B(12)) deficiency is common in Indians and a major contributor to hyperhomocysteinemia, which may influence fetal growth, risk of type II diabetes and cardiovascular disease. The purpose of this paper was to study the effect of physiological doses of B(12) and folic acid on plasma total homocysteine (tHcy) concentration.
A cluster randomized, placebo-controlled, double-blind, 2 x 3 factorial trial, using the family as the randomization unit. B(12) was given as 2 or 10 microg capsules, with or without 200 microg folic acid, forming six groups (B(0)F(0), B(2)F(0), B(10)F(0), B(0)F(200), B(2)F(200) and B(10)F(200)). Plasma tHcy concentration was measured before and after 4 and 12 months of supplementation.
From 119 families in the Pune Maternal Nutrition Study, 300 individuals were randomized. There was no interaction between B(12) and folic acid (P=0.14) in relation to tHcy concentration change and their effects were analyzed separately: B(0) vs. B(2) vs. B(10); and F(0) vs. F(200). At 12 months, tHcy concentration reduced by a mean 5.9 (95% CI: -7.8, -4.1) micromol/l in B(2), and by 7.1 (95% CI: -8.9, -5.4) micromol/l in B(10), compared to nonsignificant rise of 1.2 (95% CI: -0.5, 2.9) micromol/l in B(0). B(2) and B(10) did not differ significantly. In F(200), tHcy concentration decreased by 4.8 (95% CI: -6.3, -3.3) micromol/l compared to 2.8 (95% CI: -4.3, -1.2) micromol/l in F(0).
Daily oral supplementation with physiological doses of B(12) is an effective community intervention to reduce tHcy. Folic acid (200 microg per day) showed no additional benefit, neither had any unfavorable effects.
European journal of clinical nutrition 03/2010; 64(5):495-502. · 3.07 Impact Factor
[show abstract][hide abstract] ABSTRACT: Low plasma concentrations of vitamin B-12 are common in Indians, possibly due to low dietary intakes of animal-source foods. Whether malabsorption of the vitamin contributes to this has not been investigated. A rise in the plasma holotranscobalamin (holo-TC) concentration after a standard dose of oral vitamin B-12 has been proposed as a measure of gastrointestinal absorption in people with normal plasma vitamin B-12 concentrations. We studied 313 individuals (children and parents, 109 families) in the Pune Maternal Nutrition Study. They received 3 doses of 10 microg (n = 191) or 2 microg (n = 122) of cyanocobalamin at 6-h intervals. A rise in plasma holo-TC of > or =15% and >15 pmol/L above baseline was considered normal vitamin B-12 absorption. The baseline plasma vitamin B-12 concentration was <150 pmol/L in 48% of participants; holo-TC was <35 pmol/L in 98% and total homocysteine was high in 50% of participants (>10 micromol/L in children and >15 micromol/L in adults). In the 10 microg group, the plasma holo-TC concentration increased by 4.8-fold from (mean +/- SD) 9.3 +/- 7.0 pmol/L to 53.8 +/- 25.9 pmol/L and in the 2 microg group by 2.2-fold from 11.1 +/- 8.5 pmol/L to 35.7 +/- 19.3 pmol/L. Only 10% of the participants, mostly fathers, had an increase less than the suggested cut-points. Our results suggest that an increase in plasma holo-TC may be used to assess vitamin B-12 absorption in individuals with low vitamin B-12 status. Because malabsorption is unlikely to be a major reason for the low plasma vitamin B-12 concentrations in this population, increasing dietary vitamin B-12 should improve their status.
Journal of Nutrition 09/2009; 139(11):2119-23. · 4.20 Impact Factor
[show abstract][hide abstract] ABSTRACT: People in India have a high prevalence of low vitamin B12 status and high plasma total homocysteine (tHcy) concentrations. In a proof of principle trial, we studied the effect of oral vitamin B12 (500 microg) and/or 100 g cooked green leafy vegetables (GLV) every alternate day in a 2x2 factorial design over a 6-week period. Forty-two non-pregnant vegetarian women (age 20-50 years) were randomly allocated to four study groups. Clinical measurements were made at the beginning and at the end of the study, and blood samples were collected before, and 2 and 6 weeks after commencement of intervention. Forty women completed the trial. Twenty-six women had low vitamin B12 status (<150 pmol/L) and 24 had hyperhomocysteinemia (>15 micromol/L). GLV supplementation did not alter plasma folate or tHcy. Vitamin B12 supplementation increased plasma vitamin B12 concentration (125 to 215 pmol/L, p <0.05) and reduced tHcy concentration (18.0 to 13.0 micromol/L, p <0.05) within first 2 weeks, both of which remained stable for the next 4 weeks. Plasma vitamin B12 and tHcy concentrations did not change in those who did not receive vitamin B12, and there was no change in plasma folate concentration in any of the groups. Blood haemoglobin concentration increased marginally within first two weeks in those women who received vitamin B12 (by 3 g/L, p <0.05) and the number of women with macrocytosis decreased from 2 to zero. There was no change in vibration sensory threshold during the period of the study. High-dose per oral vitamin B12 supplementation significantly reduced plasma tHcy within 2 weeks but did not achieve normal plasma tHcy concentration even after 6 weeks. People in India have a high prevalence of low vitamin B12 status and high plasma total homocysteine (tHcy) concentrations.
Asia Pacific Journal of Clinical Nutrition 01/2007; 16(1):103-9. · 1.06 Impact Factor