Maternal intake of fish oil during pregnancy may increase risk of obesity in kids: Study

The researchers revealed that children of mothers receiving n–3 LCPUFA supplementation had an increased risk of being overweight and a tendency to increase fat percentage, increased body mass index (BMI) at age 10 years, and higher metabolic syndrome score.

There has been an increase in the prevalence of obesity and overweight in childhood and adolescence during the past 40 years, and environmental exposures during fetal life have long been suspected of playing a role. One exposure of interest is the intake of n–3 long-chained polyunsaturated fatty acids during pregnancy, mainly derived from fatty fish.

Rebecca K Vinding, University of Copenhagen, Copenhagen, Denmark, and colleagues had previously reported that children of mothers who received fish oil supplementation during pregnancy had higher BMI at 6 y of age as well as a concomitant increase in muscle-, fat, and bone mass, but no difference in fat percentage.

In the study, Dr. Vinding, and the team reported follow-up at the age of 10 years, including an assessment of metabolic health.

The study is a follow-up analysis of a randomized clinical trial conducted among 736 pregnant females and their offspring participating in the Copenhagen Prospective Studies on Asthma in Childhood Mother-child cohort.

The intervention was 2.4 g n–3 LCPUFA or control daily from pregnancy week 24 until 1 week after birth. Outcomes included body composition from Bioelectrical Impedance Analysis, anthropometric measurements, concentrations of triglycerides, blood pressure, glucose, cholesterol, and C-peptide from fasting blood samples, and a metabolic syndrome score was calculated.

Body composition and anthropometric measurements were prespecified secondary endpoints of the n–3 LCPUFA trial, and others were exploratory.

The study revealed the following findings:

• Children in the n–3 LCPUFA group had a higher mean BMI at age 10 years compared to the control group: 17.4 compared with 16.9 and a higher odds ratio of being overweight (odds ratio: 1.53). This corresponded to differences in body composition in terms of increased lean mass (0.49 kg), fat percent (0.74%), and fat mass (0.49 kg) compared to the control group.
• Children in the n–3 LCPUFA group had a higher metabolic syndrome score compared to the control (mean difference: 0.19).

In conclusion, the researchers revealed that children of mothers who received n–3 LCPUFA supplementation during pregnancy showed an increased risk of being overweight, increased BMI at age 10, and a tendency to display both an increased fat percentage and a higher metabolic syndrome score.

"These findings suggest potential adverse health effects from n–3 LCPUFA supplementation during pregnancy and need to be replicated in future independent studies," the researchers wrote.

Reference:

Vinding, R. K., Sevelsted, A., Horner, D., Vahman, N., Lauritzen, L., Hagen, C. P., Chawes, B., Stokholm, J., & Bønnelykke, K. (2024). Fish oil supplementation during pregnancy, anthropometrics, and metabolic health at age ten: A randomized clinical trial. The American Journal of Clinical Nutrition, 119(4), 960-968. https://doi.org/10.1016/j.ajcnut.2023.12.015