Are babies exposed to maternal omega-3s at risk for higher BMI?
The single-center, blinded, placebo-controlled, parallel-group study evaluated 700 mother-child pairs, concluding that children studied experienced increased BMI by 10 years old, heightened risk of being overweight and a likelihood of increased fat percentage and higher metabolic syndrome score.
“The prevalence of overweight and obesity in childhood and adolescence has increased during the past 40 years, and environmental exposures during fetal life have long been suspected of playing a role,” they wrote. “Both animal and observational human studies have shown associations between higher pregnancy intake of fish or higher blood concentrations of omega-3 LCPUFAs and lower BMI and healthier metabolic profiles in the offspring. However, no larger randomized clinical trials (RCTs) have been able to replicate these findings.”
The study is a follow-up analysis of a randomized clinical trial conducted among pregnant women and their offspring who participated in the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC) mother-child cohort. It showed that supplementation with n−3 LCPUFA in the third trimester reduced risk of chronic wheezing or asthma and infections of the lower respiratory tract in offspring by a third.
Study details
The mothers in the experimental group received a daily 4 g fish oil supplement containing 2.4 g of omega-3 LCPUFA from pregnancy (week 24) until one week after birth. The control group received an olive oil capsule placebo.
The researchers took venous fasting serum samples from the women, obtained at the COPSAC clinic, and determined HDL cholesterol, triglyceride, blood glucose and C-peptide concentrations. They also measured serum luteinizing hormone (LH) concentrations. Additionally, they calculated for metabolic syndrome. The analysis included children who received anthropometric measurements.
At the 10-year visit, parents were asked about the eating habits of their children: whether they had a propensity to comfort eat, skip meals and overeat, and whether the children ate quickly.
“Children in the n–3 LCPUFA supplementation group had a higher BMI at age 10 years compared to the control group,” the researchers added. “At the current follow-up at 10 years of age, BMI increased persistently, and we observed an increased risk of children being overweight, which we did not observe at age 6 years.”
Moreover, the experimental group tended to have higher fat mass and higher fat percentage.
Findings questioned
The increased weight and fat percentage, along with the higher metabolic syndrome severity score, at 10 years in the group of children whose mothers were supplemented with omega-3 LCPUFA were not statistically different compared to those children whose mothers were not supplemented, said Harry Rice, PhD, vice president of regulatory and scientific affairs at GOED. He questioned the study's definition of full-term pregnancy and gestational age and inconsistencies in data reporting.
“The current publication is a report of results from exploratory analyses, which are very important, but I'm troubled by the reporting and interpretation of some of the results, primarily because of concern that they may be misconstrued and poorly reported on by the popular press,” Dr. Rice said. “In general, results from exploratory analyses should be used to design future research, not draw definitive conclusions.”
He also noted that there is relatively little data on the impact of EPA/DHA supplementation during pregnancy on anthropometrics and metabolic health of the offspring but pointed to a recent study substantiating the benefits of omega-3 supplementation for reducing risk of preterm and early preterm birth.
“There's no doubt that further research is warranted in this area, not because I think there is an issue, but because there are questions that need to be answered,” Dr. Rice added.
Source: American Journal of Clinical Nutrition
doi: 10.1016/j.ajcnut.2023.12.015
“Fish oil supplementation during pregnancy, anthropometrics, and metabolic health at age ten: A randomized clinical trial”
Authors: Rebecca K. Vinding et al.
