Some folic acid crosses the placenta without ever being converted
In 368 pregnant Canadians, folic acid was present unconverted in over 90% of samples on both sides of the placenta. Nobody has established whether that matters.
What the study found
Unmetabolized folic acid reached the cord blood of 9 in 10 babies
Folic acid does not occur naturally in body tissue, so finding it circulating means the dose outran the body's ability to convert it. In 368 pregnant Canadians it was present, unconverted, in over 90% of samples on both sides of the placenta. Nobody has established whether that matters.
The caveat · One Toronto cohort, fortified flour
This measures exposure, not harm. The authors say plainly that it does not show anyone was hurt, and call for the functional consequences to be investigated. It is one Toronto cohort of 368 women in a country with mandatory fortification, so these intakes are not typical of unfortified populations, and assay differences make the comparison with older, lower published values unreliable.
What we don't know
This measures exposure, not harm. The authors say plainly that it does not show anyone was hurt, and call for the functional consequences to be investigated. It is one Toronto cohort of 368 women in a country with mandatory fortification, so these intakes are not typical of unfortified populations, and assay differences make the comparison with older, lower published values unreliable.