Discussion
milk, stunting, FM, inflammation, infections, MP
INFLAMMATION, INFECTIONS
This study showed that whether an LNS supplement contained MP or WP had no impact on increment in height, but MP tended to increase FFMI. However, compared to unsupplemented children, we identified clear benefits of LNS supplementation for both growth and tissue accretion. Whereas unsupplemented children continued to become more stunted while also gaining fat, those supplemented demonstrated 0.17 z-score recovery in height and gained FFM but not FM.Previous studies indicate that milk may improve linear growth [Multiple factors may explain the inconsistent findings in studies assessing the effect of milk or MP on growth and body composition. In the current study, MP was compared against soy protein isolate, i.e., a protein with a high protein quality score and low content of antinutrients [We found that the effect of MP on height and HAZ, but not knee-heel length was stronger in children with inflammation at baseline. While frequent infections and inflammation are known to reduce growth, possibly via down-regulation of IGF-1 [Interestingly, we found very strong interactions between WP and breastfeeding for all measures of linear growth. WP increased linear growth in breastfed children, but reduced it in non-breastfed children. A possible explanation could be the high lactose content of WP (approximately 15 g/day). The gut microbiota of breastfed children have significantly more lactobacilli and bifidobacteria [Compared to the unsupplemented children who were on a growth-faltering trajectory, LNS resulted in a 0.17 HAZ increase. This effect size is rather high compared to what has been reported in other studies. Meta-analyses evaluating the effect of complementary feeding interventions, LNS or small quantity LNS on linear growth in 6 to 23 months old children in different food-insecure or low-income settings found increases of 0.08, 0.11, and 0.14 LAZ, respectively, compared to unsupplemented children [Children receiving LNS gained on average 0.16 kg more FFM. The height-adjusted index, FFMI, also increased slightly more in LNS supplemented children, which indicates that the FFM increase is not only in proportion to increase in height, but also catch-up of FFM. In contrast, FM and FMI were not affected by LNS supplementation. Skinfold data corroborated an absence of effect of LNS on fat mass. The unsupplemented group, nevertheless, increased in FMI and tended to decline in FFMI. This unhealthy change in body composition is very different from well-nourished children from the UK, where FMI centiles decreased and FFMI centiles slowly increased between 1 and 5 years [This trial may be the first to investigate the effect of large quantity LNS on already stunted children. The main strengths are the randomized 2 × 2 factorial design with an unsupplemented control group, a high follow-up rate, and inclusion of body composition data. Limitations include lack of blinding of caregivers in regards to LNS supplementation versus no supplementation, but any change in behavior caused by this is likely to cause underestimation of the effects of LNS. There is also a risk that outcome assessors may have been unblinded to LNS supplementation in a few cases, despite all efforts to avoid it. This knowledge might have affected assessment of linear growth, but not body composition as this was measured in an automated procedure. Other limitations are the relatively short duration of the intervention and lack of long-term follow-up.There were no effects of MP isolate versus soy protein isolate or WP versus maltodextrin on linear growth or body composition among stunted children. However, in the context of continuous growth faltering, supplementation with LNS resulted in a 0.17 HAZ catch-up growth, considerable FFM accretion, an increase in FFMI, and no effects on FM or FMI. This contrasts with unsupplemented children on a stunting trajectory, who are gaining fat at the expense of FFM. Supplementation with large quantity LNS, irrespective of milk content, prevents further linear growth faltering and supports catch-up growth with accretion of fat-free tissue, but not fat. Programs using LNS to treat stunting should be considered.