Effects of Oral Nutritional Supplementation on Body Composition and Bone Health in Undernourished Children: A Randomized Controlled Study

Background/Objectives: While oral nutritional supplements (ONSs) are known to support general growth in undernourished children, their specific effects on body composition and bone health remain underexplored. This manuscript evaluates the impact of ONS combined with dietary counselling (DC) on these outcomes in Indian children aged 3 to 6.9 years at nutritional risk, within the framework of a larger randomized controlled trial assessing multiple growth parameters. Methods: This prospective, randomized controlled trial was conducted among Indian children, both male and female participants with picky eating habits and at risk of undernutrition, aged 3 to 6.9 years (height-for-age and weight-for-height below the 25th percentile per WHO Growth Standards and Growth Reference). Participants were randomized in a 1:1 ratio to receive either ONS + DC or DC alone for 6 months. Body composition, bone mineral density (BMD), and bone mineral content (BMC) were measured using dual-energy X-ray absorptiometry (DXA) at baseline and after 6 months. Group differences were analyzed to evaluate intervention effects. Results: A total of 223 children were enrolled and randomized. At 6 months, the test group showed significantly greater improvements in BMD (0.023 g/cm2) compared to the control (0.017 g/cm2; p = 0.004), and a greater gain in BMC (36.60 g vs. 28.48 g; p =0.0007). Lean mass increased significantly more in the test group (926.33 g) versus the control (801.48 g; p = 0.0401). Fat mass showed a numerical reduction in the test group (−171.42 g) compared with the control group (−114.60 g), although this difference was not statistically significant. Conclusions: These findings highlight the potential of targeted nutritional interventions to favorably improve body composition and bone health during critical growth periods in undernourished children, offering a promising approach to address early-life nutritional deficits with lasting health benefits.