Vitamin B12 supplementation improves human milk status in mothers

Maternal supplementation with vitamin B12 provides benefits on both short- and long-term human milk (HM) status, as shown in a study.

This study enrolled pregnant women in Dar es Salaam, Tanzania, between 2001 and 2004. Participants were randomized to receive either daily oral multiple micronutrient supplementation or placebo from recruitment (12‒27 weeks of gestation) through 6 weeks postpartum. A subset of participants was also randomized to receive either postnatal supplement or placebo from 6 weeks to 18 months postpartum.

The supplement contained 50 μg/d of vitamin B-12 and other vitamins. The researchers then analysed HM vitamin B12 concentrations at 6 weeks and 7 months postpartum for 412 participants.

HM vitamin B12 <310 pmol/L had a prevalence of 73.3 percent at 6 weeks postpartum and 68.4 percent at 7 months postpartum. Prenatal supplementation led to an increase in HM vitamin B12 concentration (percent difference, 34.4, 95 percent confidence interval [CI], 17.0‒54.5; p<0.001) at 6 weeks, but this effect did not persist at 7 months.

On the other hand, postnatal supplementation resulted in higher HM vitamin B12 concentration (percent difference, 15.9, 95 percent CI, 1.91‒31.9; p=0.025) at 7 months.

The researchers observed effect modification between prenatal and postnatal supplementation on HM vitamin B12 status at 7 months. Such effect was more evident among participants receiving placebo during the other period.

“[T]he prenatal supplement had a greater effect with postnatal control, and the postnatal supplement had a greater effect with prenatal control,” the researchers said.