Folate Content in Breast Milk: Findings from a Canadian Study

Research Overview

A Canadian research team conducted a study measuring the folate content in breast milk, revealing that mothers who take folic acid supplements exhibit higher levels of unmetabolized folic acid but lower levels of 5-methyl-tetrahydrofolate. Folate is essential for both mothers and infants during pregnancy and lactation.

The Role of Folic Acid

Folic acid (FA), the synthetic variant of folate, is known to reduce the risk of neural tube defects during the periconceptional period. As a result, it is commonly added to various food products, including white flour. Additionally, it is recommended that pregnant women take a multivitamin that contains at least 400μg of folic acid. However, these multivitamins may also contain the Tolerable Upper Intake Level of 1000μg.

Folate in Breast Milk

Typically, folate in breast milk is found in the form of 5-methyl-tetrahydrofolate (THF). However, for those who consume folic acid supplements, unmetabolized folic acid (UMFA) is also present.

Study Details

The findings were published in the American Journal of Clinical Nutrition as part of the MIREC (Maternal-Infant Research on Environmental Chemicals) study. Between 2008 and 2011, breast milk samples from 561 women were analyzed. Of these, 401 women consumed folic acid supplements, while 160 did not. The study assessed FA supplement usage, dietary folate intake, and measured total folate, reduced folate, UMFA, and THF levels in breast milk.

Demographics and Results

Supplement users tended to be older, more educated, and had higher annual incomes compared to non-consumers. The study found that total folate and UMFA levels were higher in women who took supplements, whereas reduced folates and THF levels were lower. Notably, the proportion of THF was greater among non-consumers, and the UMFA level in breast milk was twice as high in those consuming more than 400μg of folic acid.

Conclusions

The results indicate that while breast milk total folate content is elevated in users of folic acid supplements, this increase does not confer clear benefits, as only UMFA levels rise, rather than THF levels, particularly when folic acid intake exceeds 400μg.

Author Information

Written by: Dr. Fanni R. Eros