Thermic effect of glucose and amino acids in man studied by direct and indirect calorimetry

Abstract

I. In order to reinvestigate the classical concept of specific dynamic action of food, the thermic effect of ingested glucose (jo g) or essential amino acids (50 g) or both was measured in seven healthy male subjects dressed in shorts, by using both direct and indirect calorimetry simultaneously. Experiments were performed under conditions of thermal comfort at 28". 2. Energy 'balance' (heat production minus heat losses) was negative during the control period (mean heat deficit: -16,0+0.8 kJ/ma per h.3. Metabolic rate increased 1 3 6 + 1.8 yh after the glucose load, 172t1.40/o after amino acids, and 17'3 f 2.9 yo after both glucose and amino acids : thus there was no additive thermic effect when both nutrients were given together.4. I n contrast to the metabolic rate, heat losses were not significantly altered after nutrient ingestion; consequently, the energy 'balance' became rapidly positive.5. These results show that: (a) the food-induced thermogenesis, for a moderate energy intake, is less dependent on the nature of the nutrients than was classically admitted; (b) this increased heat production mainly induces changes in heat storage rather than in heat losses during the first hours following ingestion of a meal.An increased heat production following food ingestion was described by Rubner (1902) at the beginning of the century. Lusk (1930) showed that the stimulation of heat production varied according to the composition of the diet. Proteins had the greatest effect, increasing the metabolic rate by 30% of the ingested energy, whereas the augmentation was 6 and 4% for lipids and carbohydrates respectively. The term 'specific dynamic action' was used to describe this effect. It is to be emphasized that most of these early experiments were performcd on animals given large amounts of nutrients.The concept of specific dynamic action (SDA) has been recently challenged by various authors Ashworth, 1969; Garrow & Hawes, 1972; Garrow, 1973;Miller & Mumford, 1973). According to Miller & Mumford (1973), the term ' thermic effect' appears more appropriate to account for the incrcased metabolic rate following food ingestion.Since precise quantitative findings on the thermic effect of food in human subjects are scarce in the literature, the present study was undertaken to measurc the energy balance of subjects receiving glucose or amino acids or both. For this purpose, determinations of metabolic rate were made simultaneously with measurements of heat losses in a direct calorimeter.

Effect of beta and alpha adrenergic blockade on glucose-induced thermogenesis in man.

“…After the ingestion or infusion of glucose there is an increase in energy expenditure that has been estimated to represent 5-10% of the energy content of the administered glucose load (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). Under the present experimental conditions of euglycemic hyperinsulinemia (-100 IAU/ml), the increment in energy expenditure above postabsorptive values averaged 0.10±0.01 kcal/ min, from which it can be calculated that glucose/insulin-induced thermogenesis was 4.9±0.5%.…”

“…These six subjects served as time controls for the effect of propranolol. Study four: In nine subjects who participated in study one, after 45 min of respiratory-exchange measurements, phentolamine was administered as a prime (70 pg/kg over 5 min)-continuous (7 gg/kg-min) infusion. 1 h after starting the phentolamine infusion, a 2-h insulin clamp study was performed.…”

“…This thermogenic response to food occurs after protein, fat, and carbohydrate feeding (1-13) and has been described in man (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) as well as in animals (14)(15)(16). However, the physiologic mechanism(s) responsible for this thermogenic response have not been clarified.…”

“…After the ingestion or intravenous administration of nutrients, there is an increase in oxygen consumption and energy expenditure ( [1][2][3][4][5][6][7][8][9][10][11][12][13] that has been referred to as "nutrient" or "dietary" induced thermogenesis. This thermogenic response to food occurs after protein, fat, and carbohydrate feeding (1-13) and has been described in man (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) as well as in animals (14)(15)(16).…”

Total Energy Expenditure and Physical Activity in Children Treated with Home Parenteral Nutrition

“…This was suggested by the high correlation between SEE expressed in kilojoules per minute per kilogram FFM and the energy rate perfused by PN expressed in kilojoules per minute per kilogram of weight. This high correlation could be attributed to the thermogenic effects of nocturnal PN (32,(45)(46)(47). Indeed, when DIT was calculated as the additional EE (Fig.…”