Does Thermoregulatory Feeding Occur in Newborn Infants? A Novel View of the Role of Brown Adipose Tissue Thermo genesis in Control of Food Intake

Abstract

HIMMS-HAGEN, JEAN. Does thermoregulatory feeding occur in newborn infants? A novel view of the role of brown adipose tissue thermogenesis in control of food intake. Obes Res. 1995;3:361-369. The physiological significance of the extensive deposits of brown adipose tissue (BAT) in newborn human infants has been the subject of much experimentation and discussion. Because of its large thermogenic capacity, its function has usually been viewed as preparing the infant for producing heat in response to cold exposure at birth. Newborn infants are indeed capable of precise thermoregulation for a limited time over a rather limited range of ambient temperatures, from thermoneutrality (32-34'C) down to common "room" temperatures (24-28'C). During such mild "cold-exposure", in response to a decrease in their skin temperature, their sympathetic nervous system activity increases, and they can more than double their resting metabolic rate, principally by thermogenesis in their BAT. This review puts forward an entirely new role for BAT thermogenesis in the cyclic feeding pattern of newborn infants during their first months of life. BAT thermogenesis is proposed to be an integral element in a physiological thermoregulatory feeding control mechanism in which extended periods of very gradual cooling are interspersed with episodes of increased sympathetic nervous system activity, increased heating via BAT thermogenesis, arousal, and feeding. The cry with which the baby attracts its mother's attention is an integral part of the mechanism, as is the nutritive suckling reflex and the behavior of the mother. Initiation of feeding is attributed to a transient dip in blood glucose concentration that is due to stimulation of glucose utilization in the BAT. Termination of feeding is attributed to the high temperature brought about by the stimulated BAT thermogenesis. The duration of the urge to feed extends from the time of the cry to the time of the peak rise in temperature, when feeding stops. There is no clear circadian rhythm in core temperature in newborn infants, and meals occur at fairly frequent intervals both day and night in infants that are fed on demand. These physiological mechanisms are consistent with the limited information on phenomena attending spontaneous feeding in the newborn human infant and with what is known about the physiological control of feeding in rats. In rats, thermoregulatory feeding is defined as a feeding episode that occurs during a transient but marked increase in sympathetic nervous system activity that has several consequences.It stimulates BAT thermogenesis and increases body temperature. It produces a transient decline in blood glucose concentration secondary to the increased uptake of glucose by the stimulated BAT; this signals the initiation of the feeding episode. Subsequently the high temperature induced by BAT thermogenesis signals termination of the feeding episode. The size of the meal is determined by the balance between the capacity for BAT thermogenesis (heat production) and ambie...

Brown adipose tissue: a factor to consider in symmetrical tracer uptake in the neck and upper chest region

“…It is well known that temperature control in rodents as well as in infants in the fasting state is regulated via BAT [6,10,11,12]. Glucose turnover in correspondence with the energy balance reveals that in BAT lipids are the primary source of energy, which are directly translated into heat.…”

Arousal from hibernation and BAT thermogenesis against cold: central mechanism and molecular basis

“…The sympathetic nervous system provides the principal efferent pathway regulating BAT thermogenesis irrespective of whether the stimulus is cold exposure, diet or immobilization (Himms-Hagen, 1995;Rothwell and Stock, 1997). However, the efferent neuronal pathway from the midbrain to the sympathetic preganglionic neurons in the spinal cord innervating BAT is not completely determined.…”

Ayurvedic Approach to Cold Adaptation as Per Hemanta Seasonal Regimen: A Review

“…Brown fat also contains more capillaries than white fat, to supply the tissues with oxygen and nutrients and distribute the produced heat throughout the body. BAT is considered as an energy dispenser that consumes significant amounts of lipids and carbohydrates to produce chemical energy toward thermo genesis 9,10 . Cold temperature is a natural stimulator of BAT thermogenesis 11 .…”