Pregnant women who do not take folic acid-containing supplements are
eight times more likely to have low serum folate values, despite eating
folate-fortified foods, claims a new study.
Fortification of flour with folic acid, associated with reducing the
occurrence of neural tube defects (NTD) like spina bifida and
anencephaly, was made compulsory in the US in 1998, and has led to the
number of birth defects falling by 25 per cent.
The new study, published in the American Journal of Obstetrics and
Gynecology (Vol. 194, pp. 520-526), could have implications for Europe
where folic acid fortification is not mandatory, but is being seriously
considered by some countries like the UK and Ireland, where experts
predict its introduction is a question of 'when' and not 'if'.
The new cross-sectional study assessed the folic acid levels in the
blood of 9421 women in southern California with different
ethnicity/race, vitamin use, weight and age.
The researchers found that pregnant black and Hispanic women had lower
serum folic acid levels, despite the fact that all cereals and grain
are fortified in the US. These groups were associated with lowest
vitamin use: about 25 per cent of both groups were regular supplement
users, compared to 44 per cent of non-Hispanic whites (NHW).
"Our study shows that, even after food fortification with folic acid
in the United States, taking vitamin supplements regularly has a large
effect on serum folate levels," wrote lead author Jean Lawrence from
Kaiser Permanente Southern California.
The average serum folate level for all the women surveyed was 19.8 ng
per mL, with black women associated with an average of 17.9 ng per mL,
while NHW had average levels of 22.1 ng per mL.
The optimum serum level of folate that protects against NTD is not
known.
"The relation between folate status and NTD risk may be an inverse
linear one rather than a threshold effect, which suggests that lower
NTD rates are possible."
"Until the optimum level of serum folate is defined, women of
childbearing age should be encouraged to take a vitamin that contains
folic acid daily to ensure adequate folic acid status," wrote
Lawrence.
A limitation of the study that should be noted is that the researchers
did not collect any information about dietary folate intake and merely
related multivitamin or folic acid supplements to serum folate levels
measured by a blood test.
European strategy has been to recommend and prescribe folic acid
supplements. However, a recent study (British Medical Journal, Vol 330,
pp 571) reported that the advice did not result in women actually
taking the supplements.
The new study implies that folic acid fortification of cereals and
grains may also not be sufficient, suggesting that a policy combining
the two should be pursued to reduce the incidence of NTD.
Another possibility, suggested by some campaigners, is to raise the
level of folic acid fortification in the US from its current level of
140 micrograms per 100 grams of grain.
The Scientific Advisory Committee on Nutrition (SACN), a group of
independent experts that advises the UK's food authorities and health
department, said recently: "mandatory fortification of flour with
folate should be introduced" as long as proper consideration is given
to a number of related issues, including the level of fortification and
the form of folate to be used.
Studies have shown that folic acid is more easily absorbed from
fortified foods (85 per cent) and supplements (100 per cent) than the
folate found naturally in foods (50 per cent).
The original story may be found at:
http://www.nutraingredients.com/news/ng.asp?n=65810-folic-acid-ntd