Effects of aging on basal fat oxidation in obese humans

Thomas P.J. Solomon, Christine M. Marchetti, Raj K. Krishnan, Frank Gonzalez, John P. Kirwan

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23 Scopus citations

Abstract

Basal fat oxidation decreases with age. In obesity, it is not known whether this age-related process occurs independently of changes in body composition and insulin sensitivity. Therefore, body composition, resting energy expenditure, basal substrate oxidation, and maximal oxygen consumption (VO2max) were measured in 10 older (age, 60 ± 4 years; mean ± SEM) and 10 younger (age, 35 ± 4 years) body mass index-matched, obese, normal glucose-tolerant individuals. Fasting blood samples were also collected. Older subjects had slightly elevated fat mass (32.2 ± 7.1 vs 36.5 ± 6.7 kg, P = .16); however, waist circumference was not different between groups (104.3 ± 10.3 vs 102.1 ± 12.6 cm, P = .65). Basal fat oxidation was 22% lower (1.42 ± 0.14 vs 1.17 ± 0.22 mg/kg fat-free mass per minute, P = .03) in older subjects. The VO2max was also decreased in older individuals (44.6 ± 7.1 vs 38.3 ± 6.0 mL/kg fat-free mass per minute, P = .03); but insulin sensitivity, lipemia, and leptinemia were not different between groups (P > .05). Fat oxidation was most related to age (r = -0.61, P = .003) and VO2max (r = 0.52, P = .01). These data suggest that aging per se is responsible for reduced basal fat oxidation and maximal oxidative capacity in older obese individuals, independent of changes in insulin resistance, body mass, and abdominal fat. This indicates that age, in addition to obesity, is an independent risk factor for weight gain and for the metabolic complications of elevated body fat.

Original languageEnglish (US)
Pages (from-to)1141-1147
Number of pages7
JournalMetabolism: Clinical and Experimental
Volume57
Issue number8
DOIs
StatePublished - Aug 1 2008

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ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

Cite this

Solomon, T. P. J., Marchetti, C. M., Krishnan, R. K., Gonzalez, F., & Kirwan, J. P. (2008). Effects of aging on basal fat oxidation in obese humans. Metabolism: Clinical and Experimental, 57(8), 1141-1147. https://doi.org/10.1016/j.metabol.2008.03.021