The Effects of Nutrition on Linear Growth

Abstract

Linear growth is a complex process and is considered one of the best indicators of children's well-being and health. Genetics, epigenetics and environment (mainly stress and availability of nutrients) are the main regulators of growth. Nutrition exerts its effects on growth throughout the course of life with different, not completely understood mechanisms. Cells have a sophisticated sensing system, which allows growth processes to occur in the presence of an adequate nutrient availability. Most of the nutritional influence on growth is mediated by hormonal signals, in turn sensitive to nutritional cues. Both macro- and micro-nutrients are required for normal growth, as demonstrated by the impairment of growth occurring when their intake is insufficient. Clinical conditions characterized by abnormal nutritional status, including obesity and eating disorders, are associated with alterations of growth pattern, confirming the tight link between growth and nutrition. The precise molecular mechanisms connecting nutrition to linear growth are far from being fully understood and further studies are required. A better understanding of the interplay between nutrients and the endocrine system will allow one to develop more appropriate and effective nutritional interventions for optimizing child growth.

Keywords: children; growth; nutrition.

Figure 1

Schematic representation of the interplay between nutritional status and endocrine regulators of growth: growth hormone (GH) resistance induced by prolonged fasting impairs GH direct and insulin-like growth factor I (IGF-I) mediated action on chondrocytes. The increased secretion of fibroblast growth factor 21 (FGF21) by liver and adipose tissue in malnutrition contributes to GH resistance by reducing hepatic GH receptors expression and disrupting GH action in the growth plate. Insulin promotes growth by acting both directly on chondrocytes and indirectly, stimulating IGF-I production. Leptin, produced by adipose tissue, stimulates growth hormone-releasing hormone (GHRH) secretion by the hypothalamus and exerts a direct peripheral growth-promoting effect in the growth plate by stimulating chondrocyte proliferation and differentiation. Hypothalamic melanocortin 3 receptor (MC3R) integrates signals of metabolic status that affect body growth and sexual maturation. Micronutrients such as zinc, copper, calcium, vitamin D and macronutrients such as aminoacids, in particular leucine, exert a direct effect on the epiphyseal growth plate by influencing chondrocyte differentiation and proliferation.