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Effects of cis-9,trans-11 conjugated linoleic acid supplementation on insulin sensitivity, lipid peroxidation, and proinflammatory markers in obese men
- Source :
- Scopus-Elsevier
- Publication Year :
- 2004
- Publisher :
- Elsevier BV, 2004.
-
Abstract
- BACKGROUND We recently showed that trans-10,cis-12 (t10,c12) conjugated linoleic acid (CLA) causes insulin resistance in obese men. However, metabolic effects of the c9,t11 CLA isomer are still unknown in obese men. Because c9,t11 CLA is the predominant CLA isomer in foods and is included in dietary weight-loss products, it is important to conduct randomized controlled studies that use c9,t11 CLA preparations. OBJECTIVE We investigated the effects of c9,t11 CLA supplementation on insulin sensitivity, body composition, and lipid peroxidation in a group at high risk for cardiovascular disease. DESIGN In a randomized, double-blind, placebo-controlled study, 25 abdominally obese men received 3 g c9,t11 CLA/d or placebo (olive oil). Before and after 3 mo of supplementation, we assessed insulin sensitivity (hyperinsulinemic euglycemic clamp), lipid metabolism, body composition, and urinary 8-iso-prostaglandin F(2alpha) (a major F(2)-isoprostane) and 15-keto-dihydro-prostaglandin F(2alpha), markers of in vivo oxidative stress and inflammation, respectively. RESULTS All subjects completed the study. Compared with placebo, c9,t11 CLA decreased insulin sensitivity by 15% (P < 0.05) and increased 8-iso-prostaglandin F(2alpha) and 15-keto-dihydro-prostaglandin F(2alpha) excretion by 50% (P < 0.01) and 15% (P < 0.05), respectively. The decreased insulin sensitivity was independent of changes in serum lipids, glycemia, body mass index, and body fat but was abolished after adjustment for changes in 8-iso-prostaglandin F(2alpha) concentrations. There were no differences between groups in body composition. CONCLUSIONS A CLA preparation containing the purified c9,t11 CLA isomer increased insulin resistance and lipid peroxidation compared with placebo in obese men. Because c9,t11 CLA occurs in commercial supplements as well as in the diet, the present results should be confirmed in larger studies that also include women.
- Subjects :
- Adult
Male
medicine.medical_specialty
Linoleic acid
medicine.medical_treatment
Conjugated linoleic acid
Administration, Oral
Medicine (miscellaneous)
Blood lipids
Biology
Dinoprost
Lipid peroxidation
chemistry.chemical_compound
Insulin resistance
Double-Blind Method
Internal medicine
medicine
Humans
Linoleic Acids, Conjugated
Obesity
Aged
Nutrition and Dietetics
Cholesterol
Insulin
food and beverages
Stereoisomerism
Lipid metabolism
Middle Aged
medicine.disease
Oxidative Stress
Glucose
Endocrinology
chemistry
Body Composition
lipids (amino acids, peptides, and proteins)
Lipid Peroxidation
Insulin Resistance
Subjects
Details
- ISSN :
- 00029165
- Volume :
- 80
- Database :
- OpenAIRE
- Journal :
- The American Journal of Clinical Nutrition
- Accession number :
- edsair.doi.dedup.....972ca38500fd5a0eea69a1afe28c1865