Lack of evidence of nutritional influence on height in four low and middle-income countries.

'Nutrition influences height' has been a common concept for the last decades. Recently, contradictory results occurred when studying the effectiveness of nutritional interventions, questioning the interaction of nutrition and height. Therefore, we hypothesize that, independently of population/country, nutrition does not affect height in children and adolescents. We analyzed data from the study "Young Lives" which was performed in Ethiopia, India, Peru, and Vietnam to describe the health situation of children. We used linear mixed effect models to analyze the influence of nutrition on height. Furthermore, we used Structural Equation Modeling (SEM) to test if the commonly assumed hypothetical interaction of height and nutrition can be supported by data from low and middle-income countries. Estimates for nutrition on height of linear mixed effect models were about zero and randomly significant or non-significant in all analyzed countries. Furthermore, SEM led to the rejection of the 'nutrition influences height'-hypothesis, as data did not support the models based on this hypothesis. We do not find evidence for a nutritional influence on height in children and adolescents from low and middle-income countries. The widespread assumption that inadequate diet is reflected in short stature, which all modern nutritional interventions are based on, needs to be critically reviewed.