High fish intake during pregnancy may reduce risk of asthma in children

A new study from Denmark suggests that an increased fish intake during pregnancy may protect children against developing asthma, both early on and later in life.

The observational study investigated a potential association between self-reported fish intake of 28,936 women during pregnancy, and their children’s risk of developing early (up to 18 months) and ever-diagnosed occurrences of asthma, wheezing or allergic rhinitis up to the age of 7 years (1). The study results showed that consistently high fish intake during pregnancy (fish as a sandwich or hot meal at least 2–3 times per week) was associated with a significantly lower risk of childhood asthma diagnosis by 18 months and asthma occurrences later on (including hospitalization and medication prescription), compared with women with no fish intake. No associations with wheezing or recurrent wheezing at 18 months or with allergic rhinitis were found.

The researchers commented that these study findings support the hypothesis that increased intakes of omega-3 fatty acids may prevent the development of allergic diseases. In vitro and animal studies have demonstrated the involvement of omega-3 fatty acids in anti-inflammatory and antioxidant mechanisms (2). Results of observational and clinical trials have been inconsistent: some have found lower rates of allergic disease among children whose mothers had increased fish consumption or took fish oil supplements during pregnancy (3, 4), while others have found no associations (5).

Asthma is one of the most common chronic childhood diseases in industrialized countries. In Denmark, allergic asthma has increased almost twofold over the past 15 years (6). Most children who develop asthma do so by the age of 7–9 years, suggesting a need to investigate causal factors occurring in early life. The increase in the prevalence of allergic disease may be explained by a shift in the consumption of omega-3 fatty acids and oily fish towards a higher intake of omega-6 fatty acids.

1. Maslova E. et al. Fish intake during pregnancy and the risk of child asthma and allergic rhinitis - longitudinal evidence from the Danish National Birth Cohort. Br J Nutr. 2013; 110(7):1313-1325.
2. Calder P. C. et al. Is there a role for fatty acids in early life programming of the immune system? Proc Nutr Soc. 2010; 69:373–380.
3. Sausenthaler S. et al. Maternal diet during pregnancy in relation to eczema and allergic sensitization in the offspring at 2 y of age. Am J Clin Nutr. 2007; 85:530–537.
4. Willers S. M. et al. Maternal food consumption during pregnancy and asthma, respiratory and atopic symptoms in 5-year-old children. Thorax. 2007; 62:773–779.
5. Øien T. et al. Do early intake of fish and fish oil protect against eczema and doctor-diagnosed asthma at 2 years of age? A cohort study. J Epidemiol Community Health. 2010; 64:124–129.
6. Thomsen S. et al. Change in prevalence of asthma in Danish children and adolescents. Ann Allergy Asthma Immunol. 2004; 92:506–511.