title: Dietary conjugated linoleic acid does not adversely affect bone mass in obese fa/fa or lean Zucker rats.
abstract: Conjugated linoleic acid (CLA) elevates body ash in healthy animals. The objective of the present study was to determine if single or mixed CLA isomers improve bone mass in an obese and hyperinsulinemic state. Male (n = 120) lean and obese fa/fa Zucker rats (age, 6 weeks) were randomized to 8 weeks on a control diet or to 0.4% (w/w) cis-9, trans-11 CLA (Group 1); 0.4% (w/w) trans-10, cis-12 CLA (Group 2); 0.4% (w/w) cis-9, trans-11 CLA and 0.4% (w/w) trans-10, cis-12 CLA (Group 3); 0.4% (w/w) cis-9, trans-11 CLA, 0.4% (w/w) trans-10, cis-12 CLA, and traces of other CLA isomers (Group 4); and 0.4% (w/w) cis-9, trans-11 CLA, 0.4% (w/w) trans-10, cis-12 CLA, and 0.3% (w/w) other CLA isomers (Group 5). Bone area (BA), bone mineral content (BMC), and bone mineral density (BMD) of the whole body, spine, and femur were measured at baseline (6 weeks) and at 14 weeks of age. Effects of genotype, diet, and genotype x diet interactions were assessed using factorial analysis of variance. At 6 and 14 weeks, whole-body BA and BMC were lower in lean rats compared with fa/fa rats. Similarly, at 14 weeks, fa/fa rats had a higher spine and femur BMD despite a lower femur weight. The fa/fa rats in Groups 4 and 5 had higher adjusted whole-body BMC compared with Group 3, but not with Group 1, Group 2, or the control. In lean rats, Group 3 had a greater adjusted whole-body BMC than Groups 1 and 2, but not Group 4, Group 5, or the control. Thus, commercially available CLA mixtures and single CLA isomers do not affect bone mass in a hyperinsulinemic, obese state.
authors.affiliation: School of Dietetics and Human Nutrition, McGill University, 111 Lakeshore Road, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada.
authors.forename: Laura L
authors.initials: LL
authors.lastname: Burr
authors.forename: Carla G
authors.initials: CG
authors.lastname: Taylor
authors.forename: Hope A
authors.initials: HA
authors.lastname: Weiler
mesh_terms: D000818:Animals; D001823:Body Composition / Q000187:drug effects* / Q000502:physiology; D015519:Bone Density / Q000187:drug effects* / Q000502:physiology; D005269:Femur / Q000187:drug effects* / Q000502:physiology; D005838:Genotype; D006946:Hyperinsulinism / Q000235:genetics / Q000473:pathology; D044243:Linoleic Acids, Conjugated / Q000009:adverse effects / Q000494:pharmacology*; D008297:Male; D009765:Obesity / Q000178:diet therapy / Q000378:metabolism*; D051381:Rats; D011924:Rats, Zucker; D013131:Spine / Q000187:drug effects* / Q000502:physiology; D013237:Stereoisomerism; D013997:Time Factors
chemical_list: D044243:Linoleic Acids, Conjugated