A longitudinal study of serum cobalamins and its binding proteins in lactating women

Abstract

Objective: To examine longitudinal changes in serum cobalamins, transcobalamin (TC) and haptocorrin (HC) during lactation and to investigate the influence of vitamin B 12 supplementation on these parameters. Design: A 9-month follow-up study. Subjects and methods: Lactating mothers (N ¼ 89) including 23 supplemented with vitamin B 12 (1-18 mg/daily), 41 partly supplemented and 25 not supplemented. Blood samples collected 3 weeks (baseline) and 4 and 9 months post-partum were analysed for cobalamins, TC and HC. Both the total concentration and the cobalamin-saturated form (holo) of TC and HC were analysed. Results: No significant differences were observed in serum cobalamins or its binding proteins related to supplementation with vitamin B 12 or the duration of lactation. Serum cobalamins remained unchanged from 3 weeks to 9 months post-partum. Total TC (holoTC) (median7s.e. pmol/l) decreased between 3 weeks (710723 (85712)) and 9 months (602721 (76711)) (Po0.0001 (P ¼ 0.0002)), whereas total HC (holoHC) increased from (422711 (30079)) at 4 months to (455713 (317710)) to 9 months post-partum (Po0.0001 (Po0.0001)). Conclusion: We report a decrease in TC and an increase in HC during a 9-month period post-partum. No differences were observed between the vitamin B 12 -supplemented and the unsupplemented groups. Thus, supplementation with vitamin B 12 has no impact on the circulating level of serum cobalamins or its binding proteins in a Danish population of lactating mothers.

Scientific Opinion on Dietary Reference Values for cobalamin (vitamin B12)

“…In a subgroup of 25 mothers, a decline in breast milk cobalamin concentration was observed between two weeks and four months post partum followed by an increase at nine months post partum (Section 2.3.6.2). In a longitudinal study in 89 Danish lactating women, most of whom reported to take cobalamin supplements (1-18 μg/day, median 1 μg/day), no change in serum cobalamin concentration was observed from three weeks to nine months post partum, whereas a significant decrease in serum holoTC and an increase in haptocorrin concentrations were reported (Mørkbak et al, 2007a). Serum cobalamin, holoTC and haptocorrin concentrations after nine months showed no statistical difference between the supplemented (n = 23) and unsupplemented (n = 25) mothers.…”

Haptocorrin in humans

“…Holo-and total HC were measured as described previously (21,22). Total cobalamins were analysed employing an Advia Centaur (Bayer A/S, Leverkusen, Germany) and holoTC was analysed by an in-house ELISA (23).…”

Vitamin B-12 Status Differs among Pregnant, Lactating, and Control Women with Equivalent Nutrient Intakes

“…Infantile vitamin B-12 deficiency can lead to neurologic impairments including irritability, apathy, and developmental regression (16)(17)(18). Although a few studies have examined longitudinal changes in maternal vitamin B-12 biomarkers during lactation (14,(19)(20)(21), less is known about the impact of this reproductive state (compared to the nonlactating state) on vitamin B-12 status and requirement.…”