Effects of conjugated linoleic acid on linoleic and linolenic acid metabolism in man.
Evidence from animal studies suggests that conjugated linoleic acid (CLA) modulates plasma and tissue appearance of newly synthesized PUFA. The effects of a 1.2g (0.5 % energy) daily intake of the cis-9,trans-11 (c9,t11) isomer of CLA, trans-10,cis-12 (t10,c12) isomer of CLA or olive oil (placebo) on linoleic acid (LA) and linolenic acid (LNA) metabolism in healthy human volunteers was investigated. Fifteen subjects were fed an experimental diet and supplemented with c9,t11-CLA, t10,c12-CLA or placebo for 7 d before consuming a tracer dose of U-[(13)C]LA (50 mg) and U-[(13)C]LNA (50 mg). Blood samples were taken at 0, 2, 4, 6, 8, 24, 48, 72 and 168 h and analysed using high-precision MS. No differences between the groups in peak plasma [(13)C]LA (10.3-11.6 % of dose), [(13)C]LNA (2.5-2.9 % of dose), [(13)C]arachidonic acid (0.09-0.12 % of dose), [(13)C]EPA (0.04-0.06 % of dose) or [(13)C]DHA (0.06-0.10 % of dose) were detected. Concentration v. time curves (area under the curve) also showed no significant differences between groups. This suggests that, in healthy human subjects consuming a diet with adequate intake of essential fatty acids, CLA does not affect metabolism of LA or LNA.
Department of Applied Chemistry and Microbiology (Nutrition), University of Helsinki, PO Box 66, 00014 University of Helsinki, Finland. anu.turpeinen@helsinki.fi
Anu M
AM
Turpeinen
Sonja
S
Bärlund
Riitta
R
Freese
Peter
P
Lawrence
J Thomas
JT
Brenna
D000293:Adolescent; D000328:Adult; D002247:Carbon Isotopes; D002788:Cholesterol Esters / Q000097:blood; D004032:Diet; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D019787:Linoleic Acid / Q000097:blood*; D044243:Linoleic Acids, Conjugated / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D000069463:Olive Oil; D010938:Plant Oils / Q000494:pharmacology; D014280:Triglycerides / Q000097:blood; D017962:alpha-Linolenic Acid / Q000097:blood*
D002247:Carbon Isotopes; D002788:Cholesterol Esters; D044243:Linoleic Acids, Conjugated; D000069463:Olive Oil; D010938:Plant Oils; D014280:Triglycerides; C503589:cis-9, trans-11-conjugated linoleic acid; C496197:trans-10,cis-12-conjugated linoleic acid; D017962:alpha-Linolenic Acid; D019787:Linoleic Acid