Fish Consumption During Pregnancy and Autism

This blog post was written by Yuzhou Chen and Sinead Rhodes

Recent media coverage highlighted a study suggesting a possible link between fish consumption during pregnancy and a lower chance of autism-related outcomes, though other factors may explain the association. Headlines like “The food that can lower risk of AUTISM by 20% if eaten when pregnant, study finds” and “Eating this food during pregnancy may lower autism risk by 20%: study” have appeared in various outlets. But how accurate are these articles and do they reflect the scientific evidence?

Some media reports did a good job of citing the study’s data accurately, helping readers understand the significance of the findings. For example, the Hindustan Times mentioned that quantity of fish consumption appeared beneficial for fetal brain development and may reduce autism, aligning with recommendations for pregnant women to eat two to three servings of low-mercury fish per week. This supports existing dietary guidelines and offers reassurance to expectant mothers who may worry about fish due to mercury exposure. But these important details were not consistently communicated in some media articles.

Some articles misrepresented the study’s findings. The original research, published in The American Journal of Clinical Nutrition, analysed data from over 4,500 children in the U.S. and found that mothers who consumed fish during pregnancy had a 16% lower chance of having a child diagnosed with autism compared to those who did not eat fish. There is a discrepancy between the reported “20%” and the specific results of the study. This slight exaggeration is inaccurate and exaggerated which may mislead the public to have unrealistic expectations and wrong decision-making about health interventions.

The study found that prenatal fish intake was associated with a reduced likelihood of autism diagnosis. However, as highlighted in How to Research the Headlines, the findings only show an association, not causation which means that fish consumption may be linked to a reduced incidence of autism, which does not necessarily mean that eating fish reduces autism . There could be other factors at play. For instance, mothers who eat fish might also have access to better healthcare or healthier diets that benefit child development. There is likely genetic differences between mothers who eat different amounts of fish that are actually explaining increased autism. These other factors might actually be what’s driving the difference, not the fish itself—it’s like seeing a rise in ice cream sales alongside more sunburns. it’s not the ice cream causing sunburns but the sunny weather encouraging both.

In short, the real takeaway from the study is that prenatal fish consumption is associated with a reduced likelihood of autism diagnosis but more research is needed to better understand the potential co-factors and how they might affect the outcomes related to autism. In the meantime, adhering to existing dietary recommendations remains the best course of action. More information on the topic of pregnancy and autism can be found here.