The Implications of Growth as a Time Specific Event
Nutritional influences on human growth are commonly assessed at the whole body level as weight or length/height outcomes. These traditional variables indicate gross size, but are insensitive proxies for the dynamic processes by which nutritional components affect tissue accrual. Weight alone provides more information about calorie balance and/or hydration status than growth, and height is often attributed with growth charts, a statistical reference point. An enhanced understanding of growth biology may help elucidate the mechanisms by which nutrition modulates individual phenotypic growth patterns, and thereby better inform efforts to support healthy growth.
Individuals do not grow in skeletal size continuously, but in discrete time-specific episodes that punctuate quiescent intervals. Moreover, the body grows as a system of interrelated tissues with dynamic interactions involving time-sensitive cellular life histories. This unfolds as a collaborative chemical cross-talk between local and systemic elements. The detailed mechanisms that determine the timing of these saltatory growth events, as well as the required energy and chemical building blocks to fuel and support them, remain to be clarified. Their occurrence, however, suggests that present understanding of the nutritional needs for growth may be incomplete.