Lipid-based nutrient supplements for prevention of child undernutrition: when less may be more

Background: Both small-quantity and medium-quantity lipid-based nutrient supplements (LNS) have been used for the prevention of child undernutrition. A meta-analysis of 14 trials of small-quantity lipid-based nutrient supplements (SQ-LNS) - no LNS showed effects on length-for-age z-score {LAZ, +0.14 [95% confidence interval (CI): 0.11, 0.16]} and weight-for-length z-score [WLZ, +0.08 (0.06, 0.10)] z-scores, as well as prevalence ratios (95% CI) for stunting [LAZ < -2, 0.88 (0.85, 0.91)] and wasting [WLZ < -2, 0.86 (0.80, 0.93)]. However, little is known about the effects of medium quantity lipid-based nutrient supplements (MQ-LNS) on growth.Objectives: We aimed to examine the effects of preventive MQ-LNS (-250-499 kcal/d) provided at-6-23 mo of age on growth outcomes - no LNS or provision of SQ-LNS.Methods: We conducted a systematic review of studies of MQ-LNS for prevention, and categorized them as providing <6 mo - >6 mo of supplementation; for the latter category, we conducted a meta-analysis, with the main outcomes being change in WLZ and LAZ, and prevalence of wasting and stunting.Results: Three studies provided MQ-LNS for 3-5 mo (seasonal) for children 6-36 mo of age, and did not show consistent effects on growth outcomes. Eight studies provided MQ-LNS for 6-18 mo, generally starting at 6 mo of age; in the meta-analysis (max total n = 13,954), MQ-LNS increased WLZ [+0.09 (95% CI: 0.05, 0.13)] and reduced wasting [0.89 (0.81, 0.97)], but had no effect on LAZ [+0.04 (-0.02, 0.11)] or stunting [0.97 (0.92, 1.02)] - no LNS. Two studies directly compared SQ-LNS and MQ-LNS and showed no significant differences in growth outcomes.Conclusions: The current evidence suggests that MQ-LNS offer no added benefits over SQ-LNS, although further studies directly comparing MQ-LNS with SQ-LNS would be useful. One possible explanation is incomplete consumption of the MQ-LNS ration and thus lower than desirable intake of certain nutrients.