Study to Evaluate the Effect of Short Treatment With Nutritional Supplementation Standardized Innovative Formula, on Growth and Weight Gain in Short and Lean Prepubertal Children

Study design: Double blind, randomized, placebo controlled study.The proposed study will consist of two main segments: 1. Segment 1 is aimed to assess the effect of 6-12 months treatment with nutritional supplementation standardized formula, in short and lean prepubertal children on weight SDS, height SDS, BMI SDS and growth velocity 2. Segment 2 is aimed to explore the eating behavior of idiopathic short stature and lean prepubertal children against their sibling who have a normal height and body weight and to find out whether there is a difference in eating patterns and quality of life between idiopathic short stature and lean prepubertal children and children with normal height and body weight Segment 1 Population: 200 subjects and controls will be recruited to segment 1 of the proposed study, 100 at each group. Participants will be recruited from healthy children who will be referred to either the institute for endocrinology or the gastroenterology unit, at Schneider Children's Medical Center for growth assessment, due to low height and weight, in whom, no gastrointestinal morbidity or other underlying cause was found. Methods: Randomization \& Blinding: Participants will be randomly assigned either to the intervention group or the placebo control group. Randomization for the two study groups will be made in a ratio of 1:1. Both participants and study team will be blinded to the type of treatment that each patient will receive during the first 6 months of the study. Treatment: Participants in the intervention group will be treated with a nutritional supplementation standardized formula.Participants in the control group will be instructed to consume the same volume of formula as was calculated if they were in the intervention group. Treatment duration: The study will be divided into two treatment periods: 6 months of intervention versus active placebo followed with additional 6 months (an extension period), in which participants at the intervention g