Human milk fatty acid profile across lactational stages after term and preterm delivery: A pooled data analysis

BACKGROUND

Lipids in human milk (HM) provide the majority of energy for developing infants, as well as crucial essential fatty acids (FA). The FA composition of HM is highly variable and influenced by multiple factors. We sought to increase understanding of the variation in HMFA profiles and their development over the course of lactation, and after term and preterm delivery, using a pooled data analysis.

OBJECTIVE

To review the literature and perform a pooled data analysis to qualitatively describe an extensive FA profile (36 FAs) in term and preterm colostrum, transitional - and mature milk up to 60 days postpartum.

DESIGN

A Medline search was conducted for HMFA profile data following term or preterm delivery. The search was confined to English language papers published between January 1980 and August 2018. Studies reporting original data, extensive FA profiles in HM from healthy mothers were included. Weighted least squares (WLS) means were calculated from the pooled data using random or fixed effect models.

RESULTS

Our pooled data analysis included data from 55 studies worldwide, for a total of 4374 term milk samples and 1017 preterm milk samples, providing WLS means for 36 FAs. Patterns in both term and preterm milk were apparent throughout lactation for some FAs: The most abundant FAs (palmitic, linoleic and oleic acid) remained stable over time, whereas several long-chain polyunsaturated FAs (including ARA and DHA) seemed to decrease and short- and medium-chain FAs increased over time.

CONCLUSIONS

High heterogeneity between individual studies was observed for the reported levels of some FAs, whereas other FAs were remarkably consistent between studies. Our pooled data suggests that specific FA categories fluctuate according to distinct patterns over the course of lactation; many of these patterns are comparable between term and preterm milk.

Tracking of abdominal subcutaneous and preperitoneal fat mass during childhood. The Generation R Study

BACKGROUND

Overweight and obesity in early life tends to track into later life. Not much is known about tracking of abdominal fat. Our objective was to examine the extent of tracking of abdominal fat measures during the first six years of life.

DESIGN

We performed a prospective cohort study among 393 Dutch children followed from the age of 2 years (90% range 1.9; 2.3) until the age of 6 years (90% range 5.7; 6.2). At both ages, we performed abdominal ultrasound to measure abdominal subcutaneous and preperitoneal fat distances and areas, and we calculated the preperitoneal/subcutaneous fat distance ratio. High abdominal fat measures were defined as values in the upper 15%.

RESULTS

Abdominal subcutaneous fat distance and area, and preperitoneal fat area at 2 years were correlated with their corresponding measures at 6 years (all P-values <0.01), with the strongest coefficients for abdominal subcutaneous fat measures. Preperitoneal fat distance at the age of 2 years was not correlated with the corresponding measure at 6 years. The tracking coefficient for preperitoneal/subcutaneous fat distance ratio from 2 to 6 years was r=0.36 (P<0.01). Children with high abdominal subcutaneous fat measures at 2 years had increased risk of having high abdominal subcutaneous fat measures at 6 years (odds ratios 9.2 (95% confidence interval (CI) 4.1-20.8) and 12.4 (95% CI 5.4-28.6) for subcutaneous fat distance and area, respectively). These associations were not observed for preperitoneal fat measures.

CONCLUSIONS

Our findings suggest that both abdominal subcutaneous and preperitoneal fat mass measures track during childhood, but with stronger tracking for abdominal subcutaneous fat measures. An adverse abdominal fat distribution in early life may have long-term consequences.

Timing of lactational oestrus in intermittent suckling regimes: consequences for sow fertility

Three intermittent suckling (IS) regimes were evaluated for their effects on lactational oestrus and subsequent fertility. Control sows were weaned (CW; n = 38) at d 26 ± 2 of lactation. In IS19-7D (n=40) and IS19-14D (n=42) sows, IS started at d 19 ± 1 of lactation and sows were weaned 7 or 14 d later. In IS26-7D (n=41), IS started at d 26 ± 1 of lactation and sows were weaned 7d later. During IS, sows were separated from their piglets for 10h/day. Oestrus detection was performed twice daily without a boar and ovulation was confirmed by ultrasound once a week. In IS19-7D, IS19-14D and IS26-7D, respectively, 50%, 64% and 61% of the sows showed oestrus and ovulation during IS (P>0.05), and, of the remaining sows, 100%, 93%, and 69% showed oestrus in the first week after weaning. In CW sows, 95% showed oestrus in the first week after weaning. Parity 1 sows were considerably less likely than older parities (23% vs. 68%) to show oestrus in lactation. Pregnancy rate of the first post partum oestrus (during lactation or after weaning) was 89% (CW), 92% (IS19-7D), 80% (IS19-14D) and 77% (IS26-7D) (P>0.05) and subsequent litter size was 14.5 ± 0.5, 14.5 ± 0.6, 15.3 ± 0.5 and 15.2 ± 0.8, respectively (P>0.05). Sows mated during lactation had similar pregnancy rate and litter size to those mated after weaning. Hence, ongoing lactation for the first 2-9 d of pregnancy did not negatively affect fertility. A total of 50-64% of IS sows showed lactational oestrus, regardless of the stage of lactation. Pregnancy rates and litter size were similar to control sows, and were not affected by stage of lactation at mating.