Diets high in conjugated linoleic acid from pasture-fed cattle did not alter markers of health in young women
Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA. Nutrition research
(Impact Factor: 2.47).
01/2011; 31(1):33-41. DOI: 10.1016/j.nutres.2010.12.003
Conjugated linoleic acid (CLA) purportedly alters body composition, glucose tolerance, hepatic function, lipoprotein distributions, and other markers of health. Results are often inconclusive or contradictory, and presently, no studies have investigated the effects of naturally incorporated CLA from pasture-fed beef and dairy products on human health. We hypothesized that a diet comprised of foods naturally enriched with CLA from pasture-fed cattle would result in improved insulin sensitivity, body composition, circulating lipids, and other disease risk factors when compared to a diet comprised of commercial foods naturally low in CLA from grain-fed cattle. Eighteen healthy women 20 to 39 years of age consumed one of these 2 diets for 56 days. Balanced nutritionally complete diets comprised of 31% energy from lipid, 13% from protein, and 54% from carbohydrate were administered, with the primary difference being CLA content (CLA diet: 1.17 g/d; control diet: 0.35 g/d). The CLA diet did not result in any differences in insulin sensitivity, body composition, circulating blood lipids, or other measured disease risk factors as compared with the control diet. Thus, we conclude that a diet naturally enriched with over a 3-fold increase in CLA from pasture-fed cattle did not significantly alter selected health risk factors in healthy, premenopausal women as compared with a similar diet composed of foods from grain-fed cattle.
Available from: Paulo Emilio Correa Leite
- "For instance, studies with pharmacological formulations of c9,t11 CLA suggest beneficial health effects related to the prevention of certain types of cancer, atherosclerotic plaque formation    , and modulation of inflammatory response   . To our knowledge, there are few studies in which dairy products naturally enriched with c9,t11 CLA were used to investigate the effects of CLA on immune function in humans     . In the present study, we used the depletion–repletion study design to investigate the effects of c9,t11 CLA intake, via a naturally enriched CLA butter, on key inflammatory mediators in humans. "
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ABSTRACT: A conjugated linoleic acid (CLA) depletion-repletion study was carried out to investigate the effects of dietary c9,t11 CLA on C-reactive protein, transcription factor NFκB, metalloproteinases 2 and 9, inflammatory mediators (adiponectin, TNFα, IL-2, IL-4, IL-8, IL-10), body composition, and erythrocyte membrane composition in healthy normal-weight human adults. CLA depletion was achieved through an 8-week period of restricted dairy fat intake (depletion phase; CLA intake was 5.2±5.8 mg/day), followed by an 8-week period in which individuals consumed 20 g/day of butter naturally enriched with c9,t11 CLA (repletion phase; CLA intake of 1020±167 mg/day). The participants were 29 healthy adult volunteers (19 women and 10 men, aged 22 to 36 years), with body mass index between 18.0 and 29.9 kg m(-2). Blood samples were collected at baseline and at the end of both depletion and repletion phases. The content of CLA in erythrocytes decreased during CLA-depletion and increased during CLA-repletion. Intake of CLA-enriched butter increased the serum levels of anti-inflammatory IL-10 but reduced transcription factor NFκB in blood and serum levels of TNFα, IL-2, IL-8 and inactive metalloproteinase-9. Moreover, reduced activity of metalloproteinases 2 and 9 in serum was observed during the CLA-repletion period. In contrast, intake of CLA-enriched butter had no effects on body composition (DXA analysis) as well as on serum levels of adiponectin, C-reactive protein, and IL-4. Taken together, our results indicate that the intake of a c9,t11 CLA-enriched butter by normal-weight subjects induces beneficial changes in immune modulators associated with sub-clinical inflammation in overweight individuals.
Available from: María Guadalupe Sánchez-Otero
- "In contrast, CLA effect on human health remains ambiguous and controversial; the results vary depending on the duration of study, the metabolic state of the population group, source of CLA (supplemented or obtained from the diet), isomers composition and dosage used (Bhattacharya et al. 2006; Tricon and Yaqoob 2006). While some studies have indicated that CLA may have neutral effects on body composition and the risk markers of CVD (Smedman and Vessby 2001; Noone et al. 2002; Tricon et al. 2004; Desroches et al. 2005; Venkatramanan et al. 2010; Joseph et al. 2011), others have reported to either improve or impair markers of health, such as circulating lipids, insulin sensitivity, blood pressure, fat mass and liver necrosis (Berven et al. 2000; Riserú s et al. 2002; Eyjolfson et al. 2004; Bhattacharya et al. 2006; Tricon and Yaqoob 2006; Gaullier et al. 2007; Iwata et al. 2007; Park 2009; Racine et al. 2010; Sofi et al. 2010; Brown et al. 2011; Chen et al. 2012). VA (18:1 trans-11 VA) is the main trans fatty acid in ruminant milk fat (Turpeinen et al. 2002). "
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ABSTRACT: Saturated and trans fatty acids have been associated with the risk to develop cardiovascular diseases. However, health-promoting effects are associated with consumption of anhydrous milk fat (AMF) and ruminant trans fatty acids, such as conjugated linoleic acid (CLA) and vaccenic acid (VA) contained in the lipid fraction of milk and dairy products. The purpose of this study was to evaluate the effect of AMF naturally enriched with CLA and VA in spontaneously hypertensive rats (SHR), using sterculic oil to inhibit the conversion of VA into CLA. The administration of AMF to SHR during 7 weeks exerted beneficial effects on cardiovascular risk biomarkers (reduction of insulin, blood lipids, increase of adiponectin). When sterculic oil was included, some parameters were further ameliorated (reduction of insulin, increase of adiponectin). Sterculic oil alone reduced body weight and adiposity, and improved blood pressure, adiponectin and triglyceride levels.
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ABSTRACT: Parmi les acides linoléiques conjugués (CLA), l’isomère 10t,12c-CLA est nutritionnellement et commercialement attrayant puisqu’il a un effet anti-obésité. Cependant, cet acide gras en parallèle d’une fonte drastique du tissu adipeux, déclenche chez la souris des effets indésirables comme une insulinorésistance, une stéatose hépatique et une augmentation des risques de cholélithiase biliaire. L’objectif de cette revue est de comprendre les mécanismes à l’origine de ces effets à partir des données obtenues chez la souris et de vérifier leur existence chez l’Homme.
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