Iron is crucial to early brain development, contributing to neurotransmitter production, myelination and immune function.
Rebecca J. Schmidt, assistant professor in the Department of Public Health Sciences and a researcher affiliated with the MIND Institute, says that "Iron deficiency, and its resultant anemia, is the most common nutrient deficiency, especially during pregnancy, affecting 40% to 50% of women and their infants."
"Iron is crucial to early brain development, contributing to neurotransmitter production, myelination and immune function. All three of these pathways have been associated with autism," she adds.
In 2011, Schmidt and colleagues were the first researchers to link supplemental folic acid with reduced risk for autism spectrum disorder (ASD). Their finding was subsequently replicated in larger studies.
For their new study - the first to investigate a link between iron intake and risk of autism - the researchers analyzed data from mother-child pairs who were enrolled in the Northern California-based Childhood Autism Risks from Genetics and the Environment Study between 2002 and 2009. They publish their findings in the American Journal of Epidemiology.
The maternal daily iron intake of the participants was recorded as part of the study, as were data on vitamins, nutritional supplements and breakfast cereals consumed by the mothers while pregnant or breastfeeding.
What was the extent of the autism risk associated with iron supplements?
At the time of publication, Medical News Today did not have access to the number of participants included in the study or how many reported having children with ASD.
However, the researchers say they found that low maternal iron intake is linked with a five-fold greater risk of autism if the mother is 35 or older at the time of her child's birth, or if she has hypertension or diabetes.
"The association between lower maternal iron intake and increased ASD risk was strongest during breastfeeding, after adjustment for folic acid intake," says Schmidt. "Further, the risk associated with low maternal iron intake was much greater when the mother was also older and had metabolic conditions during her pregnancy."
"Iron deficiency is pretty common, and even more common among women with metabolic conditions. However, we want to be cautious and wait until this study has been replicated.
In the meantime, the takeaway message for women is do what your doctor recommends. Take vitamins throughout pregnancy, and take the recommended daily dosage. If there are side effects, talk to your doctor about how to address them."
Schmidt talks about the team's findings further in the video below:
Recently, MNT reported that researchers from the Nijmegen Max Planck Institute for Psycholinguistics in the Netherlands and the University of Washington claim to have identified gene mutations that may contribute to autism risk.
The researchers found that the gene TBR1, which is crucial for early brain development, and the gene FOXP2 - which is related to language development - exhibit mutations in children with severe autism.
Another recent analysis - by researchers from the Columbia University Medical Center in New York, NY - found that the brains of children and adolescents with autism have too many synapses, which affects brain function.
The authors of that study also suggested that it may be possible to reduce this excess synapse formation with a drug.In recent years, rates of autism have increased significantly, with 1 in 68 children in the US diagnosed with the disorder, compared with 1 in 150 back in 2000.