Thermogenic response to an oral glucose load in man: comparison between young and elderly subjects.

Abstract

To investigate the effect of age and change in body composition on the increase in energy expenditure consecutive to the ingestion of a 75-g glucose load, respiratory exchange measurements were performed on 24 subjects, 12 elderly (mean +/- SEM, 73 +/- 1 yr) and 12 young (25 +/- 1 yr). The body weight was comparable, 62 +/- 2 kg in the elderly group vs 61 +/- 3 in the young, but the body fat content of the elderly group was significantly greater than that of the young (29 +/- 2% vs 19 +/- 2%, p less than 0.001). The elderly group presented a slight glucose intolerance according to the World Health Organization (WHO) criteria, with a 120-min plasma glucose of 149 +/- 9 mg/dl (p less than 0.005 vs young). The postabsorptive resting energy expenditure (REE) was 0.83 +/- 0.03 kcal/min in the elderly group vs 0.98 +/- 0.04 in the young (p less than 0.02); this decrease of 15% was mainly related to the decrease in fat free mass (FFM) in the elderly group, which averaged 14%. The difference was not significant when REE was expressed per kg FFM. The glucose-induced thermogenesis (GIT) expressed as percent of energy content of the load was 6.2 +/- 0.6% in the elderly group and 8.9 +/- 0.9% in the young (p less than 0.05). It is concluded that the glucose-induced thermogenesis is decreased in elderly subjects. However, when expressed per kg FFM, the increment in energy expenditure (EE), in response to the glucose load, is not different in elderly subjects, suggesting that the decrease of thermogenesis may be attributed to the age-related decrease in FFM.

Mechanism of Increased Plasma Glucose Levels after Oral Glucose Ingestion in Normal-Weight Middle-Aged Subjects

“…The first 120 min were allocated for isotopic equilibration. Thereafter, 1 g/kg of naturally 13 Cenriched corn starch glucose was ingested.…”

“…Plasma and ingested 13 C glucose isotopic enrichment was measured by gas chromatography-combustion-isotope ratio mass spectrometry (Sira 12, VG Instrument, Middlewich, UK) [18]. 13 C enrichment of expired CO 2 was determined with isotope ratio mass spectrometry [19].…”

“…The glucose clamp is the gold standard to study insulin sensitivity, but it does not allow to study the fate of oral glucose and the influence of defective insulin secretion and slight hyperglycemia, as occur in the postprandial state in aged subjects. Using the oral glucose tolerance test (OGTT) with indirect calorimetry, Bloesch et al [13] found reduced glucose oxidation and normal non-oxidative disposal in aged subjects, but they did not measure total glucose uptake with a tracer. In the only report with the double-isotope technique in aged subjects, total glucose uptake (RdT) was reduced, but total glucose oxidation was not recorded [14].…”

Association between polymorphisms in the TRHR gene, fat-free mass, and muscle strength in older women

“…This process is associated with negative consequences among the elderly, such as loss of functional capacity and autonomy (Fleg and Lakatta 1988;Baumgartner et al 1998;Lima et al 2009), increased risk of falls (Whipple et al 1987), metabolic impairments (Bloesch et al 1988), and reduced bone mineral density (Gentil et al 2007a(Gentil et al , b, 2009Lima et al 2009). Previous reports provide evidence that sarcopenia has significant health-care cost implications that warrant efforts to understand and counteract this age-related muscle mass and strength decline (Janssen et al 2004).…”

Efeitos do treinamento resistido sobre a força muscular de idosas: uma comparação entre métodos

“…One of the consequences of natural ageing is the decline of several physiological functions, which expose the elderly to greater frailty and loss of autonomy 2 . Particularly, the muscle system undergoes changes, such as the decrease of strength and mass 3,4 (a process called sarcopenia), which is seen in both men and women 5 and may be associated with loss of autonomy, risk of falls 6 , metabolic complications 7 , reduction of mineral bone density 8 and decline in aerobic capacity 9 . Previous studies showed that the effects of sarcopenia raise healthcare costs 10 , which stresses the importance of avoiding or delaying the loss of strength and muscle mass during ageing.…”