Читать книгу Recent Research in Nutrition and Growth - Группа авторов - Страница 17

Growth saltations were originally identified in humans through daily assessments of total infant body length employing research measurement techniques [7]. The amount of growth at a saltation has been documented to include increments in the range of 0.03–1.8 cm for length, and accretions on the order of 0.02–0.05 mm for head circumference saltations in 24 h [7–11]. Unlike the growth curve images, growth is not constant. For example, rather than 365 days of less than 0.07-cm length growth each day, as implied by the interpolated length growth chart curves, an individual can grow on only 54 days during the first year of life, achieving a total accrual of 30 cm in infant linear growth by a pattern of distinct saltations that occur at irregular, aperiodic intervals. These growth saltations are separated by durations ranging from a few days to several weeks at which time no measurable growth occurs (Fig. 1). Thus, the biological process of growth in size can be visualized as a stepwise function, with pulsatile increases in size resulting in unique steps of variable heights [12]. This pattern continues throughout the developmental period, with increasing durations of stasis characterizing the changing annual growth rates. Relatively shorter stasis duration intervals characterize infancy and adolescence, a phenomenon that underlies the common assignation of these periods as “growth spurts.” The common scientific assumption that growth spurts are confined to the infant and adolescent periods and are characterized by long durations is inaccurate, reflecting an established practice of infrequent measurement sampling intervals. In summary, daily sampling clarifies that physical growth saltations, or what is commonly referred to as growth spurts, occur in minutes to hours [13], in both skeletal and head dimensions, and are how children grow across all ages.

Fig. 1. Individual children grow by saltation and stasis biology. Body growth occurs in time-specific saltations within 24 h after intervals of no growth (stasis). Unlike the mathematically interpolated traditional growth curves based on monthly measurements, daily measurements clarify that individuals grow in a stepwise pattern. Variability in the amount and timing of growth saltations underlies both variation in growth rates and individuality in the patterns by which individual children grow. These time-specific growth events offer many opportunities for the adjustment of growth rates to immediate environmental circumstances and raise questions about feeding strategies aiming to enhance growth outcomes.