Fish oil intake did not benefit body composition of obese women's newborns – NZ trial
Normal pregnancy usually leads to a pro-inflammatory state in women. However, for obese women, they experience a greater systemic inflammation during pregnancy, and this exacerbates insulin resistance in the second half of pregnancy.
Fish oil, which is insulin-sensitising, is said to help prevent the development of greater adiposity and metabolic dysfunction in the children of women who are obese during pregnancy.
In this study, published in The American Journal of Clinical Nutrition, showed that fish oil supplementation in women who were overweight or obese during pregnancy did not impact infant body composition at two weeks of age.
However, doing so has led to a reduction in triglycerides in the pregnant mothers, as well as their babies by the time they are 3-month-old.
The double-blind randomized controlled trial involved 129 women aged 18 to 40 with a body mass index (BMI) of at least 25 kg/m2.
They were randomised to take in either six capsules each containing one gram of fish oil or olive oil daily. Unlike fish oil, olive oil does not contain long-chain n-3 poly unsaturated fatty acids.
They started on the supplementation no later than 20 weeks of gestation, which continued throughout the pregnancy.
For breastfeeding mothers, the intervention continued until the baby reached three months old, or until breastfeeding stopped.
Infant body fat percentage was measured when the infants turned two weeks old.
Findings showed that infants from the fish oil group did not have a significantly lower body fat percentage than those from the olive oil group at age two weeks.
Body fat of infants from the fish oil and olive oil group was 22.1 per cent vs 21.6 per cent respectively.
However, infants from the fish oil group had a higher BMI z-score and ponderal index (p=0.017) – which measures proportionality of body growth - at age three months.
In addition, they had a significantly greater total fat mass and fat mass index, which were largely a result of greater peripheral, meaning arms and legs, but not central fat mass.
“The importance of peripheral fat mass in infants is unclear, but in children and adults, peripheral and trunk fat mass have contrasting associations with cardio-metabolic risk, with central adiposity known to be unfavourable,” said the researchers.
Infants from the fish oil group also had 39 per cent higher omega-3 index and 25 per cent lower omega-6 to omega-3 index.
Lower triglyceride level
Fish oil supplementation had lowered maternal triglycerides by 17 per cent at 30 weeks of pregnancy and infant triglycerides by 21 per cent at three months of age.
However, this did not affect maternal or infant insulin resistance.
“Of note, this is the first study to show fish oil can lower triglycerides in pregnant mothers with overweight or obesity.”
“Maternal fish oil supplementation was associated with a reduction in plasma triglycerides in the infants at 3 months of age. It is unclear if this was a direct effect of higher n-3 PUFA levels in the infants, or represented a programmed change in lipid metabolism induced by fish oil supplementation during pregnancy.
“Long-term changes in lipid metabolism could be associated with a reduced risk of metabolic dysfunction, such as dyslipidemia and other components of metabolic syndrome.
“To understand whether there are persistent changes in lipid metabolism will require additional measurement of triglycerides in the child-cohort when they are older,” the researchers said.
Source: The American Journal of Clinical Nutrition
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
Authors: Vidit V. Satokar et al