By Liz Heidelberg
A new study conducted by researchers at the Texas A&M Health Science Center College of Medicine shows that a dietary supplement could reduce the risk of autism.
Just as other supplements such as folic acid are recommended for women of childbearing age to prevent birth defects in the baby's developing brain and spinal cord, a new prenatal supplement could protect against a certain type of autism. According to research published in the journal Cell Reports, foods rich carnitine could decrease a baby’s risk of being born with autism. Previous studies have shown that genetic defects in the body’s ability to manufacture carnitine may be associated with an increased risk of autism. The new study has identified a mechanism underlying this association that suggests a strategy for preventing this type of autism risk.
Carnitine, a compound found in almost every cell in the human body, is necessary for the transport of fatty acids into mitochondria — the compartment within the cell that converts these fats into energy into energy. The latest findings show that carnitine deficiency interferes with the normal processes by which neural stem cells promote and organize embryonic and fetal brain development.
According to the Journal of the American Medical Association Pediatrics, 1 percent of Americans have autism. The annual cost of autism management in the United States alone is estimated to be at least $236 billion.
The study’s lead author is Zhigang Xie, Ph.D., assistant research scientist at the Texas A&M Health Science Center College of Medicine. Funding for the research comes from the National Institutes of Health and the Robert A. Welch Foundation. Vytas A. Bankaitis, Ph.D., the E.L. Wehner-Welch Foundation Chair in Chemistry at the Texas A&M College of Medicine, is collaborating on the research.
“The whole process has taken about six or seven years since the initial concept,” says Bankaitis. “We got our heads together, and Dr. Xie convinced me that I should look at this. This would not have been done if I was driving the bus. I just put the gas in the bus.
“Initially, we were looking into autism,” says Bankaitis. “Scientists have certain interests and certain expertise in technologies. My interests have been in metabolism of lipids, and Dr. Xie has been studying neural stem cells, in particular, for quite some time.”
Xie has refined a new technology that allows the analysis of individual neural stem cells in their natural environment in a real developing brain. “It’s very difficult to study neural stem cells in their complex natural environment,” says Xie. “But now we have a technology that makes such studies possible.”
The researchers have shown that neural stem cells unable to produce carnitine do not behave correctly in the developing brain. However, when at-risk neural stem cells receive carnitine from an outside source, they tend to behave properly.
The good news is that the body can produce carnitine, or it can be taken additionally in the diet through supplements. High quantities of carnitine are found in red meat or whole milk. It is important for a mother to consume sufficient carnitine after childbirth as well, so that the child can receive a carnitine-rich diet during breastfeeding. Carnitine supplements are already available in the market.
“Here we have indications, at least for some types of autism risk, that a dietary carnitine prevention method might be effective,” says Xie. “For some individuals, this simple nutritional supplement might really help reduce the risk of developing autism spectrum disorder. Any progress on the prevention front would be welcome given the number of people affected.”
As the autism risk gene is located on the X chromosome and males have only one X chromosome (females have two), they are at greater risk. “Inborn errors in carnitine production cause significant issues in a cell type one would believe has to contribute to autism risk,” Bankaitis said.
The next step for Bankaitis and Xie is to construct a genetic model of an animal, such as a mouse, with a carnitine defect to see if dietary carnitine has a positive effect on the animal. The abstract of the research published in Cell Reports may be viewed at http://www.cell.com/cell-reports/abstract/S2211-1247(16)00008-5.
