More fish in pregnancy linked to lower infant colic and eczema risk

A study of 1,324 mother-child pairs found that diets richer in seafood and Mediterranean-style foods were associated with fewer cases of colic and eczema at six months, although it could not establish cause and effect.

A Mediterranean-style diet during pregnancy may lower the chances that infants develop colic or eczema in their first months of life, according to a study published in JAMA Network Open. The research found that mothers who ate more fish and seafood, along with other foods associated with a Mediterranean eating pattern, had babies with fewer of these early-life problems. The findings add to growing evidence that diet in pregnancy can influence infant health, although the study does not prove cause and effect.

Researchers analysed data from 1,324 mother-child pairs in eastern Massachusetts collected between 1999 and 2003. The mothers, whose average age was 32.6, reported what they ate in early pregnancy and again at around 28 weeks’ gestation. About 40% had a history of atopy, including eczema. When the infants were assessed at roughly six months of age, around 20% had colic, 11.5% had eczema and 4.6% had both conditions.

The strongest association was seen with seafood. Each additional weekly serving of fish or seafood was linked with a 25% lower risk of infants developing colic and eczema together. A one-point rise in the Mediterranean diet score was associated with a 15% lower likelihood of the combined conditions, while each point higher on an inflammatory diet score was tied to a 34% greater odds of both problems. The study also found that the link with eczema remained even among mothers with a history of atopy.

Emily Oken, a professor in the Department of Nutrition at the Harvard T.H. Chan School of Public Health in Boston, said diet may matter because it shapes the microbiome, the gut and the immune system. Peter Lio, a dermatologist and paediatrician at Northwestern University Feinberg School of Medicine in Chicago, said seafood may be influential because it provides nutrients such as vitamin D, iodine and selenium. Still, he cautioned that eczema has many causes, including genetics, immune regulation, microbial exposures and environmental factors, and that diet is only one piece of the picture.

The findings may be especially relevant because adherence to pregnancy nutrition guidance is often poor. The article noted that only about one-third of pregnant women eat the recommended two to three servings of fish each week. Oken suggested that advice framed around a possible benefit for babies may resonate more than distant promises of reducing adult disease risk. The study was funded by the National Institutes of Health and an anonymous donor to the Harvard T.H. Chan School of Public Health, and the researchers reported no financial conflicts of interest.