The research reports that supplementation with multiple vitamins and minerals throughout pregnancy could help to boost the growth of unborn babies in non-developed countries where malnutrition can cause problems. The study also reported the ‘unexpected’ finding of a dose-response effect for iron supplementation alone, said the researchers.
Led by Dr Dominique Roberfroid from the Prince Leopold Institute of Tropical Medicine, the researchers investigated the effects of supplementation with multivitamins and minerals or iron and folic acid alone on the growth of 1500 babies in Burkina Faso.
Roberfroid told NutraIngredients that the main reason for the study was the fact that whilst many people take multi-vitamin and mineral supplements whilst pregnant, “we don’t know so far what the most appropriate dose for [these] micronutrients are when given in pregnancy.”
By investigating the possibility of a dose-response relationship, the team hoped to be able to identify a threshold point at which no further micronutrients would have an effect on growth.
But, the team instead found something rather surprising: “We found that yes, there is a dose-response for the multiple nutrients,” said Roberfroid. “The same dose-response was also seen in the control group who were taking just iron and folic acid supplements.”
However, Roberfroid said the results of the study, which took place in a developing country, cannot be extrapolated to women in developed countries: “The situation is different for pregnant women in the West compared to those in developing areas,” he warned.
“To address that question, this sort of study needs to be repeated in Europe perhaps.”
Roberfroid and his colleagues gave 1500 pregnant women in two health centres in Burkina Faso either daily supplements of 15 micronutrients, or the usual WHO-recommended supplements with only iron and folic acid. The tablets were designed to look identical in order to exclude the possible effects of the placebo effect.
The team reported that babies in the group with multiple micronutrients on average were heavier, adding that the effect of the micronutrients seemed to be cumulative – with a linear dose-response relationship.
The longer the supplements were taken, the heavier and larger the baby, explained the researchers – adding that the odds for a small-for-gestational-age baby were reduced by 40% in mothers who had taken the most tablets.
The secondary yet possibly more striking finding was that this does-response effect was also observed in the group receiving only iron and folic acid.
“Iron alone is an important effector of growth,” he said. “Even in women who are not deficient in iron, there is a benefit for fetal growth.”
“This result was not expected,” commented Roberfroid, who explained that evidence to suggest that iron had such a dose-response was ‘scant’.
The researcher explained that until now many believed that iron supplementation was mainly important to the mother. However the new findings show that the nutrient also has an important effect on growth and development of the unborn baby, he said.
Roberfroid warned that people should be cautious in extrapolating the results of the study to women in developed countries, because “they do not have the same sorts of deficiencies in micronutrients”
However, the researcher said that there is now good quality evidence to back up calls that “at least iron and folic acid should be available to women in developing countries.”
He said that whilst there was ‘pretty good’ evidence that the multi-vitamins and minerals improve growth even more than iron and folic acid, there needs to be further research in the area.
“We still don’t know the added value,” he said, warning that researchers needed to assess the longer term health of infants and children who had received such supplements throughout development in the uterus. “We are missing that long term data,” he said.
“[Because of this] we cannot propose a strong recommendation for the use of these supplements yet,” said Roberfroid. “We need to wait for the follow up data.”
Source: The Journal of Nutrition
Volume 142, Number 3, Pages 548-554, doi: 10.3945/jn.111.148015J.
“Prenatal Micronutrient Supplements Cumulatively Increase Fetal Growth”
Authors: D. Roberfroid, L. Huybregts, H. Lanou, J.P. Habicht, M.C. Henry