Maternal pre-pregnancy weight status modifies the influence of PUFAs and inflammatory biomarkers in breastmilk on infant growth

Abstract

Background Human breastmilk contains pro- and anti-inflammatory compounds and hormones that can influence infant growth. However, little is known about the specific interrelationships between these compounds and whether their effects on infant growth may be influenced by pre-pregnancy weight status. Objective The purpose of this novel, prospective cohort study was to assess the interrelationships between pro-inflammatory cytokines (TNF-α, IL-6), hormones (insulin, leptin) and PUFAs (n-6, n-3) in blood and breastmilk in early postpartum between women with normal BMI (G roup 1 , n = 18; 18.5<BMI≤24.9 kg/m 2 ) and with overweight/obesity (G roup 2 , n = 15; BMI≥25.0 kg/m 2 ) before pregnancy to determine if these components correlated to infant growth measures at age 4–8 weeks. Methods Participants were robustly phenotyped along with their infants at 4–8 weeks postpartum. TNF-α, IL-6, insulin, leptin, and n-3 and n-6 PUFAs measured in blood and breastmilk and compared between pre-pregnancy BMI groups and with infant weight, length, head circumference and % fat mass. Results Group 1 women had higher serum leptin (p<0.01) and breastmilk leptin (p<0.001) compared to Group 2. Other inflammatory markers, hormones, and total n-6, n-3 and n-6/n-3 ratio PUFAs were similar between pre-pregnancy BMI groups. No relationships were observed between whey inflammatory markers, hormones, PUFAs and growth measures in infants born to Group 2 women. However, TNF-α was positively related and, IL-6, leptin, insulin, total n-6, n-3 and n-6/n-3 PUFAs in whey breastmilk were negatively correlated to infant growth measures in infants born to Group 1 women (p<0.01). Conclusions Pro-inflammatory qualities of breastmilk were associated with infant growth measures regardless of maternal pre-pregnancy BMI. However, infants born to women with overweight or obesity demonstrated less responsive growth to breastmilk contents. More studies are needed to assess longitudinal effects of this impact.

Breastmilk Lipids and Oligosaccharides Influence Branched Short‐Chain Fatty Acid Concentrations in Infants with Excessive Weight Gain

“…Here, we demonstrate that α‐linolenic acid, oleic acid, and 3‐oxohexadecanoic acid were lower in the HW‐group breastmilk at 5 months, potentially contributing to the rapid weight gain in early life. In accordance with our results, breastmilk PUFAs are found to be negatively associated with infant weight and fat mass . Moreover, exposure to higher omega‐6/omega‐3 ratios through breastmilk was found to be contributing to the infant adipose deposition and high weight gain during the first 4 months of life .…”

The impact of maternal obesity and breast milk inflammation on developmental programming of infant growth

“…A recent study evaluating BM PUFA concentrations did not find a difference between lean and obese women. However, in this cohort there was also no difference in the serum concentration of n-6 and n-3 PUFAs between the two groups 12 . Additional studies have evaluated the impact of BM markers on infant growth with mixed findings.…”

“…Prior studies have investigated the association between BM leptin and infant growth outcomes. Several studies did not identify an association between BM leptin and infant growth 18 – 20 , while others found an inverse relationship between BM leptin and infant weight gain, length, and lean body mass over the first two years of life 12 – 17 . Leptin primarily acts on the hypothalamus to regulate food intake 51 .…”

“…This is consistent with prior studies that assessed the relationship between maternal BMI and BM IL-6 and IL-8 8 , 13 , 31 , while the association with BM IL-1β and MDA has not previously been explored. Given the known association between obesity and systemic inflammation 32 , other studies have investigated the correlation between serum and BM cytokine levels with no clear relationship identified 12 , 33 . This difference in concentration is likely related to the multiple factors stimulating or inhibiting expression of these markers in BM such as maternal and neonatal infection and the role immune cells play in the neonatal immune system 34 .…”

“…Additional studies have evaluated the impact of BM markers on infant growth with mixed findings. Some studies noted a positive association between BM marker and infant growth while others found a negative association at discrete timepoints in the first two years of life 12 – 17 . Other studies have reported no association between BM markers and infant growth 18 – 20 .…”