Accession Number : ADA269301

Title :   Effects of a High-Energy Food Supplement on Cold-Induced Thermogenesis,

Corporate Author : DEFENCE AND CIVIL INST OF ENVIRONMENTAL MEDICINE DOWNSVIEW (ONTARIO)

Personal Author(s) : Vallerand, A. L. ; Jacobs, I.

Report Date : AUG 1993

Pagination or Media Count : 29

Abstract : In previous studies, we have not been able to confirm the theory that energy substrate mobilization is a limiting factor for cold-induced thermogenesis (M) in humans. One possible explanation for the conflicting results is that the dose of energy substrates may not have been optimal. The goal of this study was to determine whether the ingestion of a high-energy food supplement (710 kcal or 2,970 kJ; Ensure Pulse) in the cold could alter: (1) M, (2) heat balance (min by min determination of heat debt (S) where S = M - heat losses, (3) rectal (T sub re) and (4) mean skin temperatures (T sub sk), (5) rates of substrate oxidation and (6) plasma levels of substrates and hormones, taken as indices of substrate mobilization. Seven healthy males were subjected to two semi-nude cold exposure tests (3h at 7 deg C, 1 m/.s wind, fasting, tests performed 1 wk apart). The ingestion of a high-energy supplement did not influence either T sub re, T sub sk, m, or S in comparison to the placebo test in the same subjects. This absence of changes was observed even though the supplement elevated carbohydrate mobilization and oxidation (P< 0.05), albeit at the expense of lipid mobilization and oxidation (P<0.05). The present results demonstrate that the ingestion of a food supplement that enhances energy substrate mobilization and oxidation does not alter cold thermogenesis, heat debt or body temperatures in humans, under normal conditions. Body temperatures, Carbohydrates, Catecholamines, Cold exposure, Core temperature, Energy substrates, Food intake, heat balance, heat loss, Heat production, Hemoconcentration, Insulin, Lipids, Plasma volume, Protein, Shivering, Thermogenesis

Descriptors :   *FOOD DEPRIVATION, *HIGH ENERGY, *COLD TOLERANCE, *LOW TEMPERATURE, BALANCE, BLOOD VOLUME, BODY TEMPERATURE, CARBOHYDRATES, CATECHOLAMINES, COMPARISON, CORES, DETERMINATION, ENERGY, FOOD, HEAT, HEAT BALANCE, HEAT LOSS, HORMONES, HUMANS, INSULIN, LIPIDS, LOSSES, MALES, MEAN, MOBILIZATION, OXIDATION, PLACEBOS, PRODUCTION, PROTEINS, RATES, SHIVERING, SUBSTRATES, TEST AND EVALUATION, THEORY, VOLUME, WIND, SKIN TESTS, BLOOD PLASMA, HEAT STRESS(PHYSIOLOGY), METABOLISM.

Subject Categories : Stress Physiology
      Biology

Distribution Statement : APPROVED FOR PUBLIC RELEASE