Autism was linked to folic acid and vitamin B12 use during pregnancy in a study conducted by researchers at the John Hopkins University Bloomberg School of Public Health. Although pregnant women and those who plan to become pregnant are encouraged to increase their folic acid intake, the study suggests too much of the nutrient could be harmful to a developing fetus. The researchers also determined high levels of vitamin B12 could significantly increase the risk of autism.
Folate, which is called vitamin B9, is one of eight B-complex vitamins. Folate occurs naturally in beans, peas, and lentils, citrus fruits, and dark leafy greens. The nutrient’s synthetic form, which is called folic acid, is commonly used in fortified cereals and vitamin supplements.
As discussed by the University of Maryland Medical Center, folate and folic acid deficiencies can cause diarrhea, forgetfulness, loss of appetite, shortness of breath, and stunted growth. However, the deficiencies are a specific concern for women who are pregnant or trying to conceive.
According to the Centers for Disease Control and Prevention, women are urged to begin taking folic acid “at least one month before she becomes pregnant and while she is pregnant” to prevent “major birth defects of the baby’s brain and spine.”
The recommended amount of the nutrient for pregnant women is between 400 and 600 mcg per day. However, in excess, folic acid may increase the risk of autism. Science Daily reports high levels of vitamin B12 are also a serious concern.
For the study, folic acid levels exceeding 59 nanomoles per liter were considered “very high,” as the levels recommended by the World Health Organization are “between 13.5 and 45.3 nanomoles per liter.”
To conduct their research, the scientists analyzed data collected from 1,391 participants in the Boston Birth Cohort between 1998 and 2013. Although the cause is unknown, the researchers found that 6 percent of the women had very high levels of vitamin B12 and 10 percent had very high levels of folic acid.
Although the cause is unknown, the researchers found 6 percent of the women tested had very high levels of vitamin B12 and 10 percent had very high levels of folic acid immediately after giving birth. The researchers further determined those women were more likely to have children who developed an autism spectrum disorder within the first three years of their life.
“… if a new mother has a very high level of folate right after giving birth… the risk that her child will develop an autism spectrum disorder doubles… high vitamin B12 levels in new moms are also potentially harmful, tripling the risk that her offspring will develop an autism spectrum disorder. If both levels are extremely high, the risk that a child develops the disorder increases 17.6 times.”
Bloomberg School’s Wendy Klag Center for Autism and Developmental Disabilities Director M. Daniele Fallin, Ph.D., who co-authored the study, admitted folic acid “is detrimental to [a] child’s development.” However, she said it is vital to “aim for optimal levels of this important nutrient.”
It is unclear whether the women participating in the study consumed too many foods or supplements containing folic acid or whether they were genetically predisposed to absorb higher quantities of the nutrient.
An Autism spectrum disorder is defined by the Mayo Clinic as “a serious neurodevelopmental disorder that impairs a child’s ability to communicate and interact with others.” Other symptoms may include behavioral issues and developmental delays.
Although an estimated one in 68 children is diagnosed with an autism spectrum disorder each year, there is no proven cause or cure.
Researchers at the John Hopkins University Bloomberg School of Public Health believe high levels of folic acid may increase the risk of autism. However, they admit more studies are necessary to prove a definitive link.
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