Everyone knows folate is vital during pregnancy and lactation; the WHO even advises continuing 400 µg daily for at least three months post-partum. Yet most mothers only ask “Am I getting enough?” and overlook a far more important question: “Which form am I taking?”

In July 2023 Scientific Reports published a head-to-head comparison:

Although total milk folate concentrations were identical in both groups, mothers who swallowed conventional folic acid secreted milk that was 28 % UMFA, whereas mothers who took the active form, 5-methyltetrahydrofolate (5-MTHF), registered only 2 % UMFA—a 14-fold difference.

Folic acid is the synthetic pteroyl-monoglutamate. Before it can be used it must be converted—via dihydrofolate reductase and the polymorphic enzyme MTHFR—into the biologically active 6(S)-5-methyltetrahydrofolate. 

 Roughly 78 % of Chinese women carry MTHFR variants that slow this conversion. Once the daily folic acid dose exceeds 200 µg, hepatic metabolism saturates and UMFA appears in plasma and, eventually, in milk.

A 2017 paper in the American Journal of Clinical Nutrition showed that UMFA competes for the folate-receptor-α on mammary epithelial cells, blocking the transfer of active folate into milk. The higher the UMFA, the less usable folate the infant actually receives.

Among the available active options, Magnafolate—a Naturalization folate—stands out: > 99.8 % purity, “practically non-toxic” per Shanghai CDC testing, and clinically documented to raise serum and red-cell folate quickly while lowering homocysteine.

Take-home message
Choose the folate form, not just the dose. For women who are pregnant or nursing, bio-active 5-MTHF (e.g., Magnafolate) is the safest bet.

Risk notice
This summary is based on the Scientific Reports paper cited below. Whether the observed UMFA rise alters infant metabolism or health remains under investigation; always personalise supplementation with professional guidance.

Key references

Lian Z-L, Liu K, Gu J-H, Cheng Y-Z. Biological characteristics and applications of folate vs. 5-methyltetrahydrofolate. China Food Additives, 2022;(2).

Khan MZ et al. Folic acid supplementation regulates milk production variables… J Anim Physiol Anim Nutr 2020;104:483-92.

Page R et al. Total folate and unmetabolized folic acid in breast milk of Canadian women. Am J Clin Nutr 2017;105:1101-9.