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Folic acid lowers the risk of children developing autism caused by pesticide exposure

Folic acid lowers the risk of children developing autism caused by pesticide exposureThe number of children diagnosed with autism has increased steadily over the past decades, and a number of factors can cause the disease. Now, scientists from the University of California and other institutions in the United States have discovered that pregnant women who get the recommended amount of folic acid or increase their intake right around the time of conception have a lower risk of giving birth to a child that develops autism caused by pesticide exposure.

It is commonly known that supplements of folic acid (vitamin B9) are important for the physiological development of the unborn child during the first three months of pregnancy. Now, a study shows that a larger intake of folic acid even helps the psychological development of the child and may lower the its risk of developing autism caused by pesticide exposure.

Autism is characterized by an unusual and often delayed development of lingual skills, communication, and social behavior. People with autism may even be hypersensitive to sensory input, have phobias, throw tantrums, and exhibit self-harming behavior.

In the study, children whose mothers took at least 800 micrograms of folic acid daily, had a significantly lower risk of developing autism – even if the mothers had been exposed to pesticides from food or agriculture, both of which are sources of exposure. The study is published in Environmental Health Perspectives in 2017. Women of childbearing age are advised to take 400 micrograms of folic acid daily, beginning right before conception and continuing at least three months into their pregnancy. The study showed that larger quantities of folic acid are required to reduce significantly the risk of autism.

Pregnant women should avoid pesticides

According to Rebecca J. Schmidt, who is a professor at the Department of Public Health Sciences and headed the study, pregnant women and those planning to become pregnant should try the best possible to avoid pesticides. A good idea is to buy organic foods, and for those who live in rural areas and risk exposure to airborne pesticides from cropdusting, it may be advisable to take extra folic acid for the sake of limiting the detrimental effect of these chemicals. Also, keep windows and doors closed when farmers are spraying their crops. Furthermore, it is recommended to avoid exposure to pesticides like Round-up, which is typically used in pine forests, parks, gardens, and driveways.

The higher the pesticide exposure before and during pregnancy – the greater the risk

The scientists used data from the CHARGE study and looked at genetic and environmental factors that are known to influence the risk of developing autism. The study included 296 children aged 2-5 years, who had been diagnosed with autism, and 220 children who had developed normally. The mothers were interviewed about pesticide exposure from the household during pregnancy and their intake of folic acid and other B vitamins. The researchers also linked to data from other reports about the use of pesticides in agriculture that could provide information about local contamination sites in close proximity to the mothers’ residences.
It turned out that children of mothers that had consumed less than 800 micrograms of folic acid daily and were exposed to pesticides from the household, were far more likely to develop autism compared with the children, whose mothers had taken 800 micrograms of folic acid and were also exposed to pesticides. Furthermore, mothers with a low folic acid intake who were exposed to pesticides three months prior to conception and up to three months after had an increased risk of giving birth to an autistic baby.
Folic acid intake levels below average combined with pesticide exposure are therefore linked to a significantly greater risk of the child developing autism. According to Rebecca J. Schmidt, pregnant women who are exposed regularly to pesticides are at greater risk of having a baby with autism.

How does folic acid protect?

In the future, researchers plan to investigate the mechanisms in folic acid that protect against autism. Folic acid is known to play a determining role in DNA methylation, a process that switches genes on and off. Folic acid is also important for DNA synthesis and repair. Both mechanisms are particularly important during fetal development, where cells divide rapidly. By consuming more folic acid, it is possible to support these mechanisms. Theoretically, these functions may even include the repair of DNA that has been damaged by pesticides.

Planning pregnancy – a new view on folic acid

Pregnant women are advised to take 400 micrograms of folic acid daily because it has been known for long that this lowers the risk of giving birth to a child with neural tube defects, congenital heart defects, and spina bifida, a condition that is linked to severe disabilities. Although these conditions are rare, it is important to take folic acid from the time you plan to become pregnant.
According to the new study, it may also be a good idea to take supplements of folic acid to lower your risk of having children with autism. Folic acid is even important for the expecting mother, her energy levels, and her mental balance.

Other factors that increase the risk of autism

Although larger quantities of folic acid can lower a baby’s risk of developing autism, the vitamin is no guarantee because there are other factors that may interfere with the mental development of the child such as:

  • other environmental toxins – including heavy metals and chemicals
  • genetic factors
  • becoming parents after the age of 35 years
  • complications during pregnancy and birth
  • overdiagnosing (since the criteria were changed in 1994)
  • lack of vitamin D (which is very common)
  • use of medical drugs that interfere with vitamin D during pregnancy (such as Vaproate against epilepsy and seizures)


Rebecca J. Schmidt et al. Combines Prenatal Pesticide Exposure and Folic Acid Intake in Relation to Autism Spectrum Disorder. Environmental Health Perspectives. 2017

Folic Acid may mitigate autism risk from pesticides

Nutrition insight. Taking Folic Acid Throughout Pregnancy May Increase Children´s Emotional Intelligence. 12 May 2017

Khaled Sall et al. Randomized controlled trial and vitamin D supplementation in children with autism spectrum disorder. Journal of Child Psychology and Psychiatry. 2016

John J Cannell. Autism Causes, Prevention and Treatment: Vitamin D Deficiency and the Explosive Rise in Autism Spectrum Disorder. Sunrise River Press. 2015

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