A comparison of the metabolism of eighteen-carbon 13C-unsaturated fatty acids in healthy women.
Altered use of different dietary fatty acids may contribute to several chronic diseases, including obesity, noninsulin-dependent diabetes mellitus, and cardiovascular disease. However, few comparative data are available to support this link, so the goal of the present study was to compare the metabolism of [(13)C]oleate, [(13)C]alpha-linolenate, [(13)C]elaidate, and [(13)C]linoleate through oxidation and incorporation into plasma lipid fractions and adipose tissue. Each tracer was given as a single oral bolus to six healthy women. Samples were collected over 8 days, and (13)C was analyzed using isotope ratio mass spectrometry. At 9 h postdose, cumulative oxidation was similar for [(13)C]elaidate, [(13)C]oleate, and [(13)C]alpha-linolenate (19 +/- 1%, 20 +/- 4%, and 19 +/- 3% dose, respectively). Significantly lower oxidation of [(13)C]linoleate (12 +/- 4% dose; P < 0.05) was accompanied by its higher incorporation into plasma phospholipids and cholesteryl esters. Abdominal adipose tissue was enriched with [(13)C]alpha-linolenate, [(13)C]elaidate, or [(13)C]linoleate within 6 h. The percentage linoleate in plasma phospholipids correlated positively with [(13)C]linoleate and [(13)C]elaidate oxidation, indicating a potential role of background diet. Conversion of [(13)C]linoleate and [(13)C]alpha-linolenate to longer chain polyunsaturates was a quantitatively minor route of utilization.
McCloy
U
U
Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada M5S 3E2. ursula.mccoy@utoronto.ca
Ryan
M A
MA
Pencharz
P B
PB
Ross
R J
RJ
Cunnane
S C
SC
D000273:Adipose Tissue / Q000378:metabolism; D000284:Administration, Oral; D000328:Adult; D001944:Breath Tests; D002247:Carbon Isotopes; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000097:blood / Q000737:chemistry* / Q000378:metabolism*; D005260:Female; D006262:Health; D006801:Humans; D010084:Oxidation-Reduction; D013997:Time Factors
D002247:Carbon Isotopes; D005231:Fatty Acids, Unsaturated