Altered materno-fetal transfer of 13C-polyunsaturated fatty acids in obese pregnant women.

BACKGROUND & AIMS: Maternal obesity at conception is considered a major predictor of offspring obesity. This could by driven at least in part by an altered placental fat transfer. However, the pathophysiological mechanisms involved are not fully understood. We investigated the in vivo materno-fetal transfer of fatty acids (FAs) in obese pregnant women using stable isotopes. METHODS: Ten obese and ten normo-weight pregnant women (control) received orally a bolus of 13C-labeled FAs 12 h before elective caesarean section: oleic acid (13C-OA), linoleic acid (13C-LA) and docosahexaenoic acid (13C-DHA). Maternal blood samples were collected at -12 (basal), -8, -4, -2, 0 h relative to the time of cesarean section. At the time of birth, arterial and venous cord bloods as well as placental tissue were collected. FAs composition was determined by gas-liquid chromatography and isotopic enrichment by gas chromatography-combustion-isotope ratio mass spectrometry. RESULTS: Maternal plasma insulin and placental weight tended to higher values in obese pregnant women although they did not present serum hyperlipidemia. Higher concentrations of 13C-LA and 13C-DHA were found in non-esterified FAs fraction in maternal plasma of obese mothers. The ratio of placental uptake for 13C-LA and 13C-DHA was lower in obese women compared to normal weight pointing toward a limited capacity of FA placental transfer, especially of essential FAs. Maternal insulin was associated to this lower placenta/maternal plasma ratio for both 13C-LA (R = -0.563, P = 0.012) and 13C-DHA (R = -0.478, P = 0.033). In addition, the ratio cord/maternal plasma of 13C-LA was significantly lower in obese women compared to controls. CONCLUSIONS: In conclusion, obese mothers without hyperlipidemia showed a reduced materno-fetal transfer of polyunsaturated FAs which could affect fetal development. This affect dietary recommendation for obese pregnant women. TRIAL REGISTRY NUMBER: ISRCTN69794527.

Effects of a high-protein intake on metabolic targets for weight loss in children with obesity: a randomized trial.

OBJECTIVE: The objective of this research is to study effects of a 4-week high-protein (HP) diet on energy intake, resting energy expenditure (REE), protein turnover and body composition in children with obesity. METHODS: In this randomized placebo-controlled single-blind crossover study, children with obesity (n = 14; mean age: 10.1 years ± 1.2 standard deviation; body mass index-standard deviation score [BMI-SDS]: 2.8 ± 0.5) received an ad libitum HP (+50 g protein per day) or normal-protein (NP) diet for 4 weeks with a washout period of ≥2 weeks. Energy intake, REE, protein turnover, weight, BMI-SDS and body composition were measured. RESULTS: No differences were found in energy intake or REE between HP and NP. There was an increased urea production and phenylalanine hydroxylation after HP compared with NP (p < 0.05). There was an increased rise in fat-free mass after HP compared with NP (∆HP: 0.8 ± 0.8 kg vs. ∆NP: 0.1 ± 0.6 kg, p < 0.05). BMI and BMI-SDS increased during the study (BMI-SDS start: 2.8 ± 0.5, end: 2.9 ± 0.5, p < 0.05) without a difference between groups. CONCLUSIONS: A 4-week HP diet with ad libitum food intake did not affect energy intake and energy expenditure in children with obesity. BMI increased, although that could be partly explained by an increase in fat-free mass.