Isotope tracer measures of meal fatty acid metabolism: Reproducibility and effects of the menstrual cycle

Ana Paola Uranga, James Levine, Michael Jensen

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


Oxidation and adipose tissue uptake of dietary fat can be measured by adding fatty acid tracers to meals. These studies were conducted to measure between-study variability of these types of experiments and assess whether dietary fatty acids are handled differently in the follicular vs. luteal phase of the menstrual cycle. Healthy normal-weight men (n = 12) and women (n = 12) participated in these studies, which were block randomized to control for study order, isotope ([3H]triolein vs. [14C]triolein), and menstrual cycle. Energy expenditure (indirect calorimetry), meal fatty acid oxidation, and meal fatty acid uptake into upper body and lower body subcutaneous fat (biopsies) 24 h after the experimental meal were measured. A greater portion of meal fatty acids was stored in upper body subcutaneous adipose tissue (24 ± 2 vs. 16 ± 2%, P < 0.005) and lower body fat (12 ± 1 vs. 7 ± 1%, P < 0.005) in women than in men. Meal fatty acid oxidation (3H2O generation) was greater in men than in women (52 ± 3 vs. 45 ± 2%, P = 0.04). Leg adipose tissue uptake of meal fatty acids was 15 ± 2% in the follicular phase of the menstrual cycle and 10 ± 1% in the luteal phase (P = NS). Variance in meal fatty acid uptake was somewhat (P = NS) greater in women than in men, although menstrual cycle factors did not contribute significantly. We conclude that leg uptake of dietary fat is slightly more variable in women than in men, but that there are no major effects of menstrual cycle on meal fatty acid disposal.

Original languageEnglish (US)
Pages (from-to)E547-E555
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Issue number3 51-3
StatePublished - Mar 2005


  • Adipose tissue biopsy
  • Indirect calorimetry
  • Isotope dilution
  • Triglyceride

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Physiology (medical)


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