In a recent study published in The American Journal of Clinical Nutrition, researchers examined the effects of fish oil supplementation on pregnant and postpartum women who are overweight or obese.
Study: Fish oil supplementation during pregnancy and postpartum in mothers with overweight and obesity to improve body composition and metabolic health during infancy: A double-blind randomized controlled trial. Image Credit: Iryna Pohrebna/Shutterstock
Background
Maternal obesity before pregnancy is a significant predictor of childhood obesity. Pregnancy typically leads to the creation of a pro-inflammatory state. Obesity in pregnant mothers leads to increased systemic inflammation, which worsens insulin resistance during the latter half of pregnancy.
Fish oil (FO) is a valuable long-chain polyunsaturated omega-3 fatty acids (PUFAs) source, specifically docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Supplementing maternal diet with n-3 PUFA may improve metabolic function in overweight or obese pregnant mothers and potentially decrease the risk of metabolic dysfunction and increased adiposity in their offspring.
About the study
In the present study, researchers investigated the impact of FO supplementation during the latter half of gestation and lactation in overweight or obese mothers on their infants.
Self-referrals were obtained via social media advertising and from lead maternity caretakers. Pregnant individuals were enrolled in the study between 12 and 20 weeks gestation from 2017 to 2020. Mothers who qualified for the study were between 18 and 40 years old, had a body-mass index (BMI) of 25 kg/m2, reported singleton pregnancy, and resided in Auckland, New Zealand. Mothers who had stopped taking an FO supplement at least two weeks before recruitment were eligible. The study involved administering either six capsules of 1 g FO or six capsules of 1 g refined olive oil (OO) to participants, starting at 20 weeks of pregnancy and continuing throughout pregnancy.
The study's main focus was to determine the fat percentage of the total body of the infant, excluding the head at two weeks of age, using whole-body dual X-ray absorptiometry (DXA) scans. The study examined various maternal secondary outcomes such as weight, height, dietary PUFA consumption, physical activity, depression score, and health-related quality of life at different time points.
Additionally, glucose, fasting insulin, and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) were measured at 30 weeks of pregnancy. The study evaluated infant secondary outcomes such as anthropometric measurements at two weeks and three months of age, as well as fasting insulin, HOMA-IR, glucose, and lipid profile at three months.
Babies' birth weights were used to categorize them as either large-for-gestational-age (LGA) or small-for-gestational-age (SGA), with the 10th and 90th percentiles serving as the cutoffs for each category according to gestational age and sex. The postnatal assessments consisted of a medical history that focused on the mother's health during the last trimester, labor, and delivery, as well as the health of the newborn. The baby's anthropometric parameters were measured, and their body composition was assessed through DXA scans.
Results
Approximately 129 females having a median age of 33.1 years were enrolled in the study and randomly assigned at a median gestation of 16.7 weeks. The participants had an average BMI of 33.1 kg/m and were mostly obese. At recruitment, both randomization groups had similar characteristics. However, the OO group had a higher percentage of nulliparous individuals, while the FO group had more participants from the most deprived quintile. Almost 105 of the 129 randomized mothers participated in the study until their infant was three months old.
The second visit took place at an average gestational age of 30.9 weeks for both groups. The groups did not show any variations in BMI, weight, or blood pressure. There were no variations in dietary PUFA consumption and physical activity between the lifestyle factors. FO supplementation led to an elevation in the omega-3 index. Supplementing with FO resulted in a 17% decrease in fasting triglyceride levels but did not affect free fatty acid concentrations. There were no significant differences in the rate of gestational diabetes or glucose, fasting insulin, or HOMA-IR levels between the OO and FO cohorts.
The intention-to-treat analysis showed that the percentage of body fat of infants at two weeks of age was comparable between the OO and FO groups. The study found no treatment impacts on body fat or lean mass percentage when considering the measurements taken at two weeks and three months of age in repeated measures assessment. Infants born to mothers who received FO supplements had a higher BMI z-score and ponderal index at three months. The FO group's infants had a higher fat mass index and total fat mass, mainly due to increased peripheral fat mass rather than central fat mass.
The study conducted subgroup analyses on 64 obese mothers who attended a 30-week pregnancy analysis and provided a blood specimen as well as their infants. During pregnancy, FO treatment led to a 19% decrease in maternal triglycerides but also resulted in a 53% increase in high-sensitivity C-reactive protein (hsCRP). Infant auxology, body composition, and metabolic profile showed no variations.
Conclusion
The study findings showed that supplementation with FO did not impact the body composition of infants at two weeks of age. The study found that the intervention lowered triglyceride levels in pregnant mothers and their three-month-old infants. FO supplementation had a sex-specific effect on the cord blood omega-3 index, indicating potential sex-specific metabolic variations in the offspring. Long-term impact on body composition and detailed metabolic evaluations that are not possible during infancy need to be performed by following up with the children within this cohort throughout childhood.
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