In a 2018 cross-sectional study, researchers measured vitamin B12 concentrations in milk samples from 26 vegan, 22 vegetarian, and 26 non-vegetarian breastfeeding women in the U.S. They also surveyed the women’s use of vitamin B12-containing supplements.
There was no significant difference between the three groups either in the concentration of vitamin B12 in their breast milk or in the percentage of women who had low levels of vitamin B12 in their milk. Based on the cut-off value used in this study, 17.6% of all participants had low levels; however, the adequate concentration of vitamin B12 in breast milk is not firmly established.
The majority of the women (78.4%) took a supplement that contained vitamin B12. All but 2 of the vegan women used a vitamin B12 supplement.
The women in this study were well-educated and had access to resources such as vegan organizations and online breastfeeding support groups—similar results may not be seen in all populations. However, among vegan women in this population, use of vitamin B12 supplements is common and the B12 levels in breastmilk don’t differ from those of non-vegan women.
See our section on Daily Needs for information on getting adequate vitamin B12 on a vegan diet.
1. Pawlak R, Vos P, Shahab-Ferdows S, Hampel D, Allen L, Perrin M. Vitamin B-12 content in breast milk of vegan, vegetarian, and nonvegetarian lactating women in the United States. Am J Clin Nutr. 2018 June; 146(5): 1125–1131. doi: 10.3945/jn.115.228189.