Relationship between postabsorptive respiratory exchange ratio and plasma free fatty acid concentrations

Michael Dennis Jensen, Jiří Bajnárek, Sang Yeoup Lee, Soren Nielsen, Christina Koutsari

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The relationship between overnight postabsorptive (fasting) respiratory exchange ratio (RER) and plasma FFA concentrations was addressed using data from three separate protocols, each of which involved careful control of the antecedent diet. Protocol 1 examined the relationship between fasting RER and the previous daytime RER. In Protocol 2 fasting, RER and plasma palmitate concentrations were measured in 29 women and 31 men (body mass index <30 kg·m-2). Protocol 3 analyzed data from Nielsen et al. (Nielsen, S., Z. K. Guo, J. B. Albu, S. Klein, P. C. O'Brien, M. D. Jensen. 2003. Energy expenditure, sex and endogenous fuel availability in humans. J. Clin. Invest. 111: 981-988.) to understand how fasting RER and palmitate concentrations relate within individuals during four consecutive measurements. The results were as follows: 1) Fasting RER was correlated (r = 0.74, P < 0.001) with the previous day's average RER, and less so with RER variability. 2) Fasting RER was correlated (r = -0.39, P = 0.007) with fasting plasma palmitate concentrations. 3) The pattern of the RER/palmitate relationship was similar within individuals and between individuals; a negative slope was observed significantly more often than a positive slope (χ 2 test; P < 0.001). Our findings suggest that, despite a fixed food quotient, the slight departures from energy equilibrium in a controlled General Clinical Research Center environment can effect plasma FFA concentrations. We suggest that including indirect calorimetry as part of FFA metabolism studies may aid in data interpretation.

Original languageEnglish (US)
Pages (from-to)1863-1869
Number of pages7
JournalJournal of Lipid Research
Volume50
Issue number9
DOIs
StatePublished - 2009

Fingerprint

Plasma Exchange
Palmitates
Nonesterified Fatty Acids
Fasting
Plasmas
Calorimetry
Nutrition
Metabolism
Availability
Indirect Calorimetry
Energy Metabolism
Body Mass Index
Diet
Food
Research

Keywords

  • Energy balance
  • Food quotient
  • Indirect calorimetry
  • Lipolysis
  • Palmitate

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Endocrinology

Cite this

Relationship between postabsorptive respiratory exchange ratio and plasma free fatty acid concentrations. / Jensen, Michael Dennis; Bajnárek, Jiří; Lee, Sang Yeoup; Nielsen, Soren; Koutsari, Christina.

In: Journal of Lipid Research, Vol. 50, No. 9, 2009, p. 1863-1869.

Research output: Contribution to journalArticle

Jensen, Michael Dennis ; Bajnárek, Jiří ; Lee, Sang Yeoup ; Nielsen, Soren ; Koutsari, Christina. / Relationship between postabsorptive respiratory exchange ratio and plasma free fatty acid concentrations. In: Journal of Lipid Research. 2009 ; Vol. 50, No. 9. pp. 1863-1869.
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