Why is Breastfeeding a Protective Factor Against Autism?

Autism Protection from Breastfeeding Theory Explained

Healthy Gut Microbiome

One explanation as to how breastfeeding confers protection against autism comes from the understanding that breastfeeding or the provision of breastmilk is essential for the development of gut microflora and a healthy gut microbiome. A child’s gut microbiome plays an important role in the development of their immune and neural systems (Manohar et al., 2018).

• Aside from the well-established genetic causes of autism, another possible cause of ASD could stem from immunological mechanisms (Manohar et al., 2018).
• The customized components of breastmilk such as Immunoglobulin A, transforming growth factor-B, interleukin-10, erythropoietin, and lactoferrin encourage development of intestinal immune defenses and prevent inflammation (Manohar et al., 2018).
• The nutritional composition of breastmilk is imperative for neural and long-term cognitive development. Breastmilk contains just the right amount of essential fatty acids, growth factors, and antioxidants to support a child’s neural and cognitive development (Manohar et al., 2018).

Insulin-Like Growth Factor-1

         Insulin-Like Growth Factor-1 or IGF-1 is a key component of breastmilk and in children is responsible for the regulation of cells called oligodendrocytes. Oligodendrocytes are responsible for the production of myelin (Westmark, 2021). Myelin is a substance that forms around nerves in a process called myelination and is important for early neurodevelopment as it helps to establishes a foundation for brain connectivity, encouraging development of cognitive and behavioral function (Deoni et al., 2018).

• It has been hypothesized that deficient levels of IGF-1 result in abnormal myelination of neurons in a child’s brain and can lead to the development of autism (Westmark, 2021).
• In the brain of someone with autism, nerve axons have been found to have a thinner coating of myelin (Westmark, 2021).
• Children with ASD have displayed lower levels of IGF-1 in both their cerebrospinal fluid and urine (Westmark, 2021).
• When compared to cow’s milk or infant formula, breastmilk contains higher quantities of IGF-1 (Westmark, 2021).

Oxytocin Transfer

         Oxytocin is a hormone transferred to infants through their mother’s breastmilk and has been shown to enhance social development in infants (Cheng et al., 2019).

• Transference of oxytocin has been found to enhance social bonding, social recognition, and overall neurodevelopment in infants (Cheng et al., 2019).
• Oxytocin’s role in encouraging social bonding in infants may reduce the risk of autism development (Cheng et al., 2019).

What Does the Evidence Say?

         Let’s take a look at what experts in the field are finding through their research on breastfeeding and autism spectrum disorder.

• A study of over 188,000 Korean children found breastfed children had a decreased risk of developing autism when compared to formula fed children (Kim et al., 2021).
• A multicenter study based in China of 1,389 children with ASD and 1,190 children without ASD found breastfeeding for at least 12 months beneficial in autism symptom reduction. The same study also found a link between shorter breastfeeding duration and autistic children (Xiang et al., 2023).
• A 2018 study comparing children with ASD to their typically developing siblings found that infants fed formula early in life had odds for developing ASD six times greater than the odds of breastfed infants (Manohar et al., 2018).
• A meta-analysis of seven studies including 3,270 children, found not breastfeeding to be a risk factor for ASD with 1.81 times greater odds of ASD development in children who were not breastfed (Jenabi et al., 2023).
• A study of over 6,000 toddlers in China found toddlers who were not breastfed for the first 6 months of life had increased odds of being diagnosed with ASD when compared to toddlers who were breastfed (Huang et al., 2021).

See You Next Time

Come back next time for tips on how your child’s primary care provider can support you in breastfeeding.

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