Excessive amounts of folic acid could be harmful to the fetus, said researchers at John Hopkins Bloomberg School of Public Health on Wednesday. High levels of the nutrient in mothers, may double the risk of autism and spectrum disorders among newborns.

Folic acid is a B vitamin, which helps the body make healthy new cells, said the National Institutes of Health Office of Dietary Supplements. Pregnant women are recommended to take the nutrient since it helps in the neurodevelopment of babies.

The risk of developing autism may double in newborns when mothers have four times more folate than what is considered adequate. Very high levels of the B12 vitamin are also harmful, tripling the risk of developing the disorder in babies.

When levels of folic acid and B12 are extremely high, the risk of developing autism increases 17.6 times, said researchers. Preliminary findings will be presented May 13 at the International Meeting for Autism Research in Baltimore.

This could be a “case of too much of a good thing”

Folate can be found in leafy green vegetables, fruits, dried beans, peas, nuts and enriched bread. It can also be taken as a dietary supplement. Daniele Fallin, Ph.D. and study’s senior author, said it is fundamental to know which are the optimal levels of this “important nutrient”.

“Adequate supplementation is protective: That’s still the story with folic acid, We have long known that a folate deficiency in pregnant mothers is detrimental to her child’s development. But what this tells us is that excessive amounts may also cause harm,” said Fallin in a statement.

One out of 68 children in the United States has been identified with autism spectrum disorder. Folate is necessary to cell growth. One out of four women of reproductive age in the country have insufficient levels of folic, said the Centers for Disease Control and Prevention (CDC).

Autism spectrum disorder is a group of developmental disabilities that can cause communication and social challenges, said the CDC. Researchers studied data from 1,391 mother-child pairs in the Boston Birth Cohort. The latter is considered to be a low-income population, said study authors.

Data was collected from 1998 to 2013. The mothers were followed for several years. 1 out 10 women in the study had excessive amounts of folic acid, said the John Hopkins Bloomberg School of Public Health in a press release issued Wednesday.

Six percent of women who participated in the study had levels of B12 vitamin, that exceeded guidelines. The World Health Organization said that the optimum amount of folate needed by a pregnant woman varies between 13.5 and 45.3 nanomoles per liter.

More investigation is needed

Researchers concluded that more investigation is needed to define which is the perfect amount of folic acid that a pregnant woman actually needs. A theory proposes that the body expels the nutrients that are not necessary. However, that may not occur with folate and vitamin b12.

“This research suggests that this could be the case of too much of a good thing, We tell women to be sure to get folate early in pregnancy. What we need to figure out now is whether there should be additional recommendations about just what an optimal dose is throughout pregnancy,” said study lead author Ramkripa Raghavan.

Source: John Hopkins Bloomberg School of Public Health Press Release