Supplemental Conjugated Linoleic Acid Consumption Does Not Influence Milk Macronutrient Contents in all Healthy Lactating Women Effect of conjugated linoleic acid and omega-3 fatty acid supplementation on inflammatory and oxidative stress markers in atherosclerotic patients An oil mixture with trans-10, cis-12 conjugated linoleic acid increases markers of inflammation and in vivo lipid peroxidation compared with cis-9, trans-11 conjugated linoleic acid in postmenopausal women. A diet rich in conjugated linoleic acid and butter increases lipid peroxidation but does not affect atherosclerotic, inflammatory, or diabetic risk markers in healthy young men. Effects of conjugated linoleic acid plus n-3 polyunsaturated fatty acids on insulin secretion and estimated insulin sensitivity in men Conjugated linoleic acid supplementation for 8 weeks does not affect body composition, lipid profile, or safety biomarkers in overweight, hyperlipidemic men. A high intake of trans fatty acids has little effect on markers of inflammation and oxidative stress in humans. The role of conjugated linoleic acid in reducing body fat and preventing holiday weight gain Conjugated linoleic acid supplementation reduces peripheral blood mononuclear cell interleukin-2 production in healthy middle-aged males. The effects of conjugated linoleic acid supplementation on immune function in healthy volunteers Conjugated linoleic acid supplementation for twelve weeks increases lean body mass in obese humans. Supplementation With Conjugated Linoleic Acid Causes Isomer-Dependent Oxidative Stress and Elevated C-Reactive Protein: A Potential Link to Fatty Acid-Induced Insulin Resistance Relation between the intake of milk fat and the occurrence of conjugated linoleic acid in human adipose tissue. Conjugated linoleic acid improves airway hyper‐reactivity in overweight mild asthmatics Effects of Conjugated Linoleic Acid Supplementation During Resistance Training on Body Composition, Bone Density, Strength, and Selected Hematological Markers Effect of Conjugated Linoleic Acid, Vitamin E, Alone or Combined on Immunity and Inflammatory Parameters in Adults with Active Rheumatoid Arthritis: A Randomized Controlled Trial The effect of conjugated linoleic acid on plasma lipoproteins and tissue fatty acid composition in humans Conjugated linoleic acid induces lipid peroxidation in humans Effects of cis-9,trans-11 and trans-10,cis-12 conjugated linoleic acid on immune cell function in healthy humans. Dietary supplementation with cis-9,trans-11 conjugated linoleic acid and aortic stiffness in overweight and obese adults. Conjugated linoleic acid supplementation for 1 y reduces body fat mass in healthy overweight humans. Effect of conjugated linoleic acid on body fat accretion in overweight or obese children. Time-dependent effects of safflower oil to improve glycemia, inflammation and blood lipids in obese, post-menopausal women with type 2 diabetes: a randomized, double-masked, crossover study.
The term “ conjugated linoleic acid ” ( CLA ) refers to a group of positional and geometric isomers that are derived from linoleic acid and are found primarily in meat and milk products from ruminant animals . Due to the array of putative benefits associated with various forms of CLA , there has been recent interest in supplementing human diets with these fatty acids especially when weight loss is desired . However , in many animal models , CLA has been shown to decrease milk fat production . There is some concern , therefore , that maternal CLA supplementation during lactation might inadvertently decrease nutrient supply to the nursing infant . However , there is only limited research on the effect of CLA consumption on milk fat content in women . Based on previously published work from our laboratory , we hypothesized that CLA supplementation would reduce the milk fat percentage in lactating women in a dose-dependent manner . Breastfeeding women ( n = 12 ) were assigned r and omly to treatments of 4 g/day safflower oil ( SFO ) , 2 g/day CLA plus 2 g/day SFO , or 4 g/day CLA in a double blind , 3 × 3 Latin square design . Conjugated linoleic acid supplements contained approximately equal amounts of cis9,trans11–18:2 and trans10,cis12–18:2 ; the two most common isoforms of CLA . Milk was collected by complete breast expression on the last day ( day 5 ) of each intervention period and analyzed for macronutrient and fatty acid composition . On day 4 of each intervention period , infant milk consumption was estimated by 24 h weighing of the infant . Washout periods were 9 days in length . We observed a dose-dependent increase in the concentrations of cis9,trans11–18:2 and trans10,cis12–18:2 in the milk fat . However , we detected neither a change in overall macronutrient composition nor infant milk consumption . These data do not support those obtained from animal models or our previous human work suggesting that consumption of CLA mixtures necessarily reduces milk fat . It is possible that either ( 1 ) the interpretation of our previously published data should be reevaluated , and /or ( 2 ) there are important intra- and inter-species differences in this regard BACKGROUND Cardiovascular disease is the major cause of morbidity , mortality , and disability in Iranian people . Inflammation and oxidative processes are key components of cardiovascular disease . The aim of this study was to evaluate the effect of conjugated linoleic acids ( CLA ) and omega-3 fatty acid ( ω-3 fatty acids ) supplementation on inflammation markers and oxidative stress in atherosclerotic patients . METHODS This study was a two-month clinical , r and omized trial . 90 volunteers who referred to Emam Reza Heart Clinic of Shiraz University of Medical Sciences ( Shiraz , Iran ) from February to March 2011 and had the inclusion criteria of this study were selected . Participants were classified into 3 groups receiving 3 g/d CLA , 1920 mg/d ω-3 , or placebo for 2 months . C-reactive protein ( CRP ) , interleukin-6 ( IL-6 ) , malondialdehyde ( MDA ) , and glutathione peroxidase ( GPx ) were measured before and after supplementation . RESULTS The hs-CRP level decreased significantly in both the omega-3 and CLA group ( P < 0.05 ) . IL-6 reduced significantly in the ω-3 group , but the reduction of IL-6 levels in the CLA group was not significant . GPx increased in the CLA and omega-3 groups ( P < 0.05 ) . MDA level decreased significantly in both omega-3 and CLA groups ( P < 0.05 ) . Comparison between the groups indicates a significant change in CRP levels in the ω-3 group relative to the control group . However , other indices did not cause any significant change in the ω-3 and CLA groups in comparison to the control group . CONCLUSION Diet supplementation with CLA and ω-3 can have a beneficial effect on some indices of inflammatory and oxidative stress A mixture of trans-10 , cis-12 ( t10,c12 ) and cis-9 , trans-11 ( c9,t11 ) conjugated linoleic acid ( CLA mixture ) reduced atherosclerosis in animals , thus the effect of these isomers on endothelial dysfunctions leading to inflammation and atherosclerosis is of interest . We gave 75 healthy postmenopausal women a daily supplement of 5.5 g of oil rich in either CLA mixture , an oil rich in the naturally occurring c9,t11 CLA ( CLA milk ) , respectively , or olive oil for 16 wk in a double-blind , r and omized , parallel intervention study . We sample d blood and urine before and after the intervention . The ratios of total cholesterol : HDL cholesterol and concentrations of C-reactive protein , fibrinogen , and plasminogen activator inhibitor-1 were significantly higher in women supplemented with the CLA mixture than in those supplemented with CLA milk .  Plasma triacylglycerol was significantly higher and HDL cholesterol was lower in women supplemented with the CLA mixture than with olive oil . Both CLA supplements increased lipid peroxidation , a marker of in vivo oxidative stress measured as urinary free 8-iso-prostagl and in F(2alpha ) . However , the CLA mixture increased lipid peroxidation more than the CLA milk did . The plasma cytokines interleukin-6 and tumor necrosis factor-alpha were not affected by the treatments , nor were any of the other variables measured . In conclusion , oil containing trans-10,cis-12 CLA has several adverse effects on classical and novel markers of coronary vascular disease , whereas the c9,t11 CLA isomer is more neutral , except for a small but significant increase in lipid peroxidation compared with olive oil Intake of conjugated linoleic acid ( CLA ) has been demonstrated to beneficially affect risk markers of atherosclerosis  and  diabetes in rats . CLA is naturally found in milk fat , especially from cows fed a diet high in oleic acid , and increased CLA intake can occur concomitantly with increased milk fat intake . Our objective was to investigate the effect of CLA as part of a diet rich in butter as a source of milk fat on risk markers of atherosclerosis , inflammation , diabetes type II , and lipid peroxidation .  A total of 38 healthy young men were given a diet with 115 g/d of CLA-rich fat ( 5.5 g/d CLA oil , a mixture of 39.4 % cis9 , trans11 and 38.5 % trans10 , cis12 ) or of control fat with a low content of CLA in a 5-wk double-blind , r and omized , parallel intervention study . We collected blood and urine before and after the intervention . The fatty acid composition of plasma triacylglycerol , cholesterol esters , and phospholipids reflected that of the intervention diets . The CLA diet result ed in increased lipid peroxidation measured as an 83 % higher 8-iso-prostagl and in F2alpha concentration compared with the control , P < 0.0001 . We observed no other significant differences in the effect of the interventions diets . In conclusion , when given as part of a diet rich in butter , a mixture of CLA isomers increased lipid peroxidation but did not affect risk markers of cardiovascular disease , inflammation , or fasting insulin and glucose concentrations Background / Objectives : Dietary addition of either conjugated linoleic acid ( CLA ) or n-3 long-chain polyunsaturated fatty acids ( n-3 LC-PUFAs ) has been shown to alter adiposity and circulating lipids , risk markers of cardiovascular diseases . However , CLA may decrease insulin sensitivity , an effect that may be reversed by n-3 LC-PUFA . Thus , the potential of CLA plus n-3 LC-PUFA to affect insulin secretion and sensitivity in non-diabetic young and old , lean and obese subjects was tested . Subjects/ Methods : CLA ( 3 g daily ) plus n-3 LC-PUFA ( 3 g daily ) or control oil ( 6 g daily ) was given to lean ( n=12 ; BMI 20–26 kg/m2 ) or obese ( n=10 ; BMI 29–35 kg/m2 ) young ( 20–37 years old ) or lean ( n=16 ) or obese ( n=11 ) older men ( 50–65 years ) for 12 weeks . The study had a double-blind , placebo-controlled r and omized crossover design , and primary end points were insulin secretion and sensitivity during a st and ardized meal test , evaluated by modeling glucose , insulin and C-peptide data . Results : The combination was well tolerated . There was no significant difference in fasting levels of glucose , insulin or C-peptide after CLA/n-3 LC-PUFA treatment compared with control oil . Neither insulin secretion nor estimated sensitivity was affected by CLA/n-3 LC-PUFA in lean or obese young subjects or in older lean subjects . However , in older obese subjects , estimated insulin sensitivity was reduced with CLA/n-3 LC-PUFA compared with control ( P=0.024 ) . Conclusions : The results do not support beneficial effects of CLA/n-3 LC-PUFA for β-cell dysfunction or insulin resistance in humans but suggest that insulin sensitivity in older obese subjects is reduced The usefulness of conjugated linoleic acid ( CLA ) as a nutraceutical remains ambiguous . Our objective was , therefore , to investigate the effect of CLA on body composition , blood lipids , and safety biomarkers in overweight , hyperlipidemic men . A double-blinded , 3-phase crossover trial was conducted in overweight ( BMI ≥ 25 kg/m(2 ) ) , borderline hypercholesterolemic [ LDL-cholesterol ( C ) ≥ 2.5 mmol/L ] men aged 18 - 60 y. During three 8-wk phases , each separated by a 4-wk washout period , 27 participants consumed under supervision in r and om order 3.5 g/d of safflower oil ( control ) , a 50:50 mixture of trans 10 , cis 12 and cis 9 , trans 11 ( c9 , t11 ) CLA : Clarinol G-80 , and c9 , t11 isomer : c9 , t11 CLA . At baseline and endpoint of each phase , body weight , body fat mass , and lean body mass were measured by DXA . Blood lipid profiles and safety biomarkers , including insulin sensitivity , blood concentrations of adiponectin , and inflammatory ( high sensitive-C-reactive protein , TNFα , and IL-6 ) and oxidative ( oxidized-LDL ) molecules , were measured . The effect of CLA consumption on fatty acid oxidation was also assessed . Compared with the control treatment , the CLA treatments did not affect changes in body weight , body composition , or blood lipids . In addition , CLA did not affect the β-oxidation rate of fatty acids or induce significant alterations in the safety markers tested . In conclusion , although no detrimental effects were caused by supplementation , these results do not confirm a role for CLA in either body weight or blood lipid regulation in humans Consumption of industrial trans fatty acids ( iTFA ) increases LDL cholesterol , decreases HDL cholesterol , and is strongly associated with a higher risk of cardiovascular disease ( CVD ) . However , changes in circulating cholesterol can not explain the entire effect . Therefore , we studied whether iTFA and conjugated linoleic acid ( CLA ) affect markers of inflammation and oxidative stress .  Sixty-one healthy adults consumed each of 3 diets for 3 wk , in r and om order . Diets were identical except for 7 % of energy provided by oleic acid ( control diet ) , iTFA , or CLA . At the end of the 3 wk , we measured plasma inflammatory markers IL-6 , C-reactive protein , tumor necrosis factor receptors I and II ( TNF-RI and -RII ) , monocyte chemotactic protein-1 and E-selectin , and urinary 8-iso-PGF(2α ) , a marker of lipid peroxidation . Consumption of iTFA caused 4 % lower TNF-RI concentrations and 6 % higher E-selectin concentrations compared with oleic acid ( control ) and had no significant effect on other inflammatory markers . CLA did not significantly affect inflammatory markers . The urine concentration of 8-iso-PGF(2α ) [ geometric mean ( 95 % CI ) ] was greater after the iTFA [ 0.54 ( 0.48 , 0.60 ) nmol/mmol creatinine ] and the CLA [ 1.2 ( 1.1 , 1.3 ) nmol/mmol creatinine ] diet periods than after the control period [ 0.45 ( 0.41 , 0.50 ) nmol/mmol creatinine ; P < 0.05 ] . In conclusion , high intakes of iTFA and CLA did not substantially affect plasma concentrations of inflammatory markers , but they increased the urine 8-iso-PGF(2α ) concentration . However , it is unlikely this plays a major role in the mechanism by which iTFA increase the risk of CVD . However , more research is needed to fully underst and the implication s of these findings Objective : The incidence of obesity and overweight in the US has increased considerably during the past two decades and currently affects 65 % of the adult population . Research has indicated that small , yet irreversible , gains during the holiday season contribute to increases in weight during adulthood . Conjugated linoleic acid ( CLA ) , a naturally occurring dietary fatty acid , has been found to reduce weight gain and dramatically decrease fat mass in animals . Although research in humans has shown inconsistent results , most studies have been of insufficient duration or have utilized body composition methods that are less accurate than the currently accepted criterion . Design : R and omized , double-blind , placebo-controlled study of 3.2 g/day CLA for 6 months . Subjects : Forty healthy , overweight subjects ( age : 18–44 years ; body mass index : 25–30 kg/m2 ) Measurements : Body composition by the four-compartment model , resting metabolic rate ( RMR ) by indirect calorimetry , self-reported physical activity and dietary intake , and blood chemistries were determined at baseline and after 6 months . Body weight was measured monthly during the pre-holiday season ( August – October ) , holiday season ( November – December ) and post-holiday season ( January – March ) . Adverse events were assessed monthly . Results : Compared to CLA , the placebo group showed a greater rate of weight gain during the holiday season ( P=0.01 ) . Within the placebo group , holiday weight change was significantly greater compared to the pre-holiday period ( August – October ) ( P=0.03 ) . Six-month change in body composition was improved with CLA compared to placebo ( P=0.02 ) , and body fat was significantly reduced within the CLA group ( −1.0±2.2 kg , P=0.05 ) . CLA had no effect on RMR , physical activity or dietary intake . The rate of reported negative emotions decreased significantly with CLA , although there was no difference in any other category of adverse event . In comparison to the placebo , CLA did not affect insulin resistance , blood lipids and markers of liver function or markers of inflammation , with the exception of a significant decrease in a biomarker of endothelial dysfunction . Conclusion : CLA  supplementation among overweight adults significantly reduced body fat over 6 months and prevented weight gain during the holiday season . Although no adverse effects were seen , additional studies should evaluate the effect of prolonged use of CLA Conjugated linoleic acid ( CLA ) refers to geometric and positional isomers of linoleic acid . Animal studies have shown that CLA modulates the immune system and suggest that it may have a therapeutic role in inflammatory disorders . This double-blind placebo-controlled intervention trial investigated the effects of CLA supplementation on indices of immunity relating to cardiovascular disease ( CVD ) in a cohort of healthy middle-aged male volunteers . Subjects were r and omly assigned to supplement their diet with 2.2 g 50:50 isomeric blend of cis 9 , trans 11 ( c9 , t11)-CLA and trans 10 , cis 12 ( t10 , c12)-CLA or placebo daily for 8 weeks . Interleukin ( IL ) 2 , IL-10 and tumour necrosis factor ( TNF ) alpha were measured in the supernatant of cultured unstimulated and concanavalin A ( Con A)-stimulated peripheral blood mononuclear cells ( P BMC ) by ELISA . Serum IL-6 and plasma CRP were measured by ELISA and plasma fibrinogen by automated clotting assay . Gene expression was investigated by real-time RT-PCR . CLA supplementation significantly reduced Con A-stimulated P BMC IL-2 secretion ( 37.1 % ; P=.02 ) . CLA supplementation had no significant effect on transcription of IL-2 .  CLA supplementation had no direct significant effects on P BMC TNFalpha or IL-10 secretion . Other inflammatory markers associated with CVD , including IL-6 , CRP and fibrinogen , were not affected by CLA supplementation . This study showed that CLA supplementation reduced P BMC IL-2 secretion from Con A-stimulated P BMC but lacked effect on other markers of the human inflammatory response Objective : To assess the effects of dietary supplementation using two isomeric blends of conjugated linoleic acid ( CLA ) on immune  function in healthy human volunteers . Design : Double-blind , r and omised , placebo-controlled intervention trial . Subjects and intervention : A total of 55 healthy volunteers ( n=20 males , n=35 females ) were r and omised into one of three study groups who received 3 g/day of a fatty acid blend containing a 50:50 cis-9 , trans-11 : trans-10 , cis-12 CLA isomer blend ( 2 g CLA ) , and 80:20 cis-9 , trans-11 : trans-10 , cis-12 ( 80:20 ) CLA isomer blend ( 1.76 g CLA ) or linoleic acid ( control , 2 g linoleic acid ) for 8 weeks . Results : Supplementation with the 80:20 CLA isomer blend significantly ( P≤0.05 ) enhanced PHA-induced lymphocyte proliferation . CLA  decreased basal interleukin (IL)-2 secretion ( P≤0.01 ) and increased PHA-induced IL-2 and tumor necrosis factor α ( TNFα ) production ( P≤0.01 ) . However , these effects were not solely attributable to CLA as similar results were observed with linoleic acid . CLA supplementation had no significant effect on peripheral blood mononuclear cells IL-4 production , or on serum-soluble intercellular adhesion molecule-1 ( sICAM-1 ) or plasma prostagl and in E2 ( PGE2 ) or leukotreine B4 ( LTB4 ) concentrations . Conclusions : This study shows that CLA supplementation had a minimal effect on the markers of human immune function . Furthermore , supplementation with CLA had no immunological benefit compared with linoleic acid . Sponsorship : CLA supplements were provided by Loders Croklaan Conjugated linoleic acid ( CLA ) alters body composition in animal models , but few studies have examined the effects of CLA supplementation on body composition and clinical safety measures in obese humans . In the present study , we performed a r and omized , double-blind , placebo-controlled trial to examine the changes in body composition and clinical laboratory values following CLA ( 50:50 ratio of cis-9 , trans-11 and trans-10 , cis-12 isomers ) supplementation for 12 wk in otherwise healthy obese humans . Forty-eight participants ( 13 males and 35 females ) were r and omized to receive placebo ( 8 g safflower oil/d ) , 3.2 g/d CLA , or 6.4 g/d CLA for 12 wk . Changes in body fat mass and lean body mass were determined by dual-energy X-ray absorptiometry . Resting energy expenditure was assessed by indirect calorimetry . Clinical laboratory values and adverse-event reporting were used to monitor safety . Lean body mass increased by 0.64 kg in the 6.4 g/d CLA group ( P < 0.05 ) after 12 wk of intervention . Significant decreases in serum HDL-cholesterol and sodium , hemoglobin , and hematocrit , and significant increases in serum alkaline phosphatase , C-reactive protein , and IL-6 , and white blood cells occurred in the 6.4 g/d CLA group , although all values remained within normal limits . The intervention was well tolerated and no severe adverse events were reported , although mild gastrointestinal adverse events were reported in all treatment groups . In conclusion , whereas CLA may increase lean body mass in obese humans , it may also increase markers of inflammation in the short term Background —Conjugated linoleic acids ( CLAs ) , a group of fatty acids shown to have beneficial effects in animals , are also used as weight loss supplements . Recently , we reported that the t 10 c 12 CLA-isomer caused insulin resistance in abdominally obese men via unknown mechanisms . The aim of the present study was to examine whether CLA has isomer-specific effects on oxidative stress or inflammatory biomarkers and to investigate the relationship between these factors and induced insulin resistance . Methods and Results —In a double-blind placebo-controlled trial , 60 men with metabolic syndrome were r and omized to one of 3 groups receiving t 10 c 12 CLA , a CLA mixture , or placebo for 12 weeks . Insulin sensitivity ( euglycemic clamp ) , serum lipids , in vivo lipid peroxidation ( determined as urinary 8-iso-PGF2&agr ; [ F2-isoprostanes ] ) , 15-ketodihydro PGF2&agr ; , plasma vitamin E , plasma C-reactive protein , tumor necrosis factor-&agr ; , and interleukin-6 were assessed before and after treatment . Supplementation with t 10 c 12 CLA markedly increased 8-iso-PGF2&agr ; ( 578 % ) and C-reactive protein ( 110 % ) compared with placebo ( P < 0.0001 and P < 0.01 , respectively ) and independent of changes in hyperglycemia or dyslipidemia . The increases in 8-iso-PGF2&agr ; , but not in C-reactive protein , were significantly and independently related to aggravated insulin resistance . Oxidative stress was related to increased vitamin E levels , suggesting a compensatory mechanism . Conclusions —t 10 c 12 CLA supplementation increases oxidative stress and inflammatory biomarkers in obese men . The oxidative stress seems closely related to induced insulin resistance , suggesting a link between the fatty acid-induced lipid peroxidation seen in the present study and insulin resistance . These unfavorable effects of t 10 c 12 CLA might be of clinical importance with regard to cardiovascular disease , in consideration of the widespread use of dietary supplements containing this fatty acid BACKGROUND Conjugated linoleic acid ( CLA ) is a group of naturally occurring fatty acids mainly present in fats from ruminants . CLA has been shown to be a potential anticarcinogen . OBJECTIVE In this study , the relation between bovine milk fat intake and the occurrence of CLA in human adipose tissue was investigated . DESIGN One hundred twenty-three men weighed and recorded the foods they consumed for 1 wk . Afterward , recall interviews were conducted by telephone monthly for 7 consecutive months to inquire about food consumption during the previous 24 h. The entire dietary recording procedure was repeated once . The fatty acid composition of adipose tissue and serum was analyzed . RESULTS The average amount of one isomer of CLA--9-cis,11-trans-octadecadienoic acid (9c,11t-18:2)--as a percentage of total fatty acids was found to be 0.50 % in adipose tissue and 0.25 % in serum . The amount of 9c,11t-18:2 in adipose tissue was significantly correlated with milk fat intake ( r = 0.42 ) . The percentage of 9c,11t-18:2 in both adipose tissue and in serum was strongly correlated with myristoleic acid ( 14:1 ) . CONCLUSION The amount of 9c,11t-18:2 in human adipose tissue was significantly related to milk fat intake Background Conjugated linoleic acids ( CLA ) are naturally occurring fatty acids that have multiple biological properties including the regulation of metabolic , proliferative and immune processes Conjugated linoleic acids ( CLA ) are essential fatty acids that have been reported in animal studies to decrease catabolism , promote fat loss , increase bone density , enhance immunity , and serve as an antiatherogenic and anticarcinogenic agent . For this reason , CLA has been marketed as a supplement to promote weight loss and general health . CLA has also been heavily marketed to resistance-trained athletes as a supplement that may help lessen catabolism , decrease body fat , and promote greater gains in strength and muscle mass during training . Although basic research is promising , few studies have examined whether CLA supplementation during training enhances training adaptations and /or affects markers of health . This study evaluated whether CLA supplementation during resistance training affects body composition , strength , and /or general markers of catabolism and immunity . In a double-blind and r and omized manner , 23 experienced , resistance-trained subjects were matched according to body mass and training volume and r and omly assigned to supplement their diet with 9 g·d-1 of an olive oil placebo or 6 g·d-1 of CLA with 3 g·d-1 of fatty acids for 28 days . Prior to and following supplementation , fasting blood sample s , total body mass , and dual-energy X-ray absorptiometry ( DEXA ) determined body composition , and isotonic bench press and leg press 1 repetition maximums ( 1RMs ) were determined . Results revealed that although some statistical trends were observed with moderate to large effect sizes , CLA supplementation did not significantly affect ( p > 0.05 ) changes in total body mass , fat-free mass , fat mass , percent body fat , bone mass , strength , serum substrates , or general markers of catabolism and immunity during training . These findings indicate that CLA does not appear to possess significant ergogenic value for experienced resistance-trained athletes Background : Little information about the effects of conjugated linoleic acids ( CLAs ) on inflammation and immune function in humans is available . This study investigated the effects of CLAs , with and without Vitamin E on immunity and inflammatory parameters in adults with active rheumatoid arthritis ( RA ) . Methods : In a double-blind clinical trial , 78 patients were r and omly divided into four groups , each group receiving one of the following daily supplement for 3 months ; group C : 2.5 g CLAs , group E : 400 mg Vitamin E , group CE : CLAs plus Vitamin E , group P : Placebo .  Cytokines , matrix metalloproteinase 3 ( MMP-3 ) and citrullinated antibody ( CCP-A ) were measured by ELISA method and Vitamin E by high-performance liquid chromatography . Results : Consider statistical methods there were no significant differences between groups in cytokines interleukin-2 ( IL-2 ) , IL-4 , tumor necrosis factor-α ( TNF-α ) , IL-1β , IL-2/IL-4 , CCP-A white blood cells and neutrophils , lymphocyte , monocytes , and eosinophils numbers . TNF-α decreased in all groups , but its reduction was significant in group CE . IL-1β increased in groups P ( P = 0.004 ) and E ( P = 0.041 ) but the difference between group P and CE was significant . IL-4 decreased in groups C , CE and E ( P = 0.03 , P = 0.03 , P = 0.07 respectively ) . IL2 did not change significantly within groups . CCP-A increased in groups P ( P = 0.035 ) and E ( P = 0.05 ) , while it decreased in groups CE ( P = 0.034 ) . CCP-A and MMP-3 decrease were significant between groups P and CE . MMP-3 reduction was significant in group CE . Conclusions : Co-supplementation CLAs and Vitamin E may be effective in the level of inflammatory markers in RA patients Conjugated linoleic acid ( CLA ) has been suggested by some animal studies to possess antiatherogenic properties . To determine , in humans , the effect of dietary CLA on blood lipids , lipoproteins , and tissue fatty acid composition , we conducted a 93-d study with 17 healthy female volunteers at the Metabolic Research Unit of the Western Human Nutrition Research Center . Throughout the study , subjects were fed a low-fat diet [ 30 energy percent ( en% ) fat , 19 en% protein , and 51 en% carbohydrate ] that consisted of natural foods with the recommended dietary allowances for all known nutrients . After a 30-d stabilization period , subjects were r and omly assigned to either an intervention group ( n=10 ) supplemented daily with capsules containing 3.9 g of CLA or a control group ( n=7 ) that received an equivalent amount of sunflower oil . The CIA capsules ( CLA 65 % ) contained four major cis/trans geometric isomers ( 11.4 % 9 cis-,11 trans-18∶2 ; 10.8 % 8 trans-,10 cis-18∶2 ; 15.3 % 11 cis-,13 trans-18∶2 ; and 14.7 % 10 trans- , 12 cis-18∶2 ) and their corresponding cis/cis ( 6.74 % total ) and trans/trans ( 5.99 % total ) varieties in smaller amounts . Fasting blood was drawn on study days 30 ( end of the stabilization period ) , 60 ( midpoint of the intervention period ) , and 93 ( end of the intervention period ) . Adipose tissue sample s were taken on days 30 and 93 . CLA supplementation for 63 d did not change the levels of plasma cholesterol , low density lipoprotein cholesterol , high density lipoprotein cholesterol , and triglycerides . The weight percentage of CLA in plasma increased from 0.28±0.06 to 1.09±0.31 ( n=10 , P<0.05 ) after the supplementation . The 9 cis-,11 trans-isomer was the most prominent variety followed by the 11 cis-,13 trans- and 10 trans-,12 cis-isomers in lesser amounts . CLA in adipose tissue was not influenced by the supplementation ( 0.79±0.18 to 0.83±0.19 wt% ) ( n=10 ) and the 9 cis-,11 trans-variety was the only isomer present . Thus , contrary to findings from some animal studies , CLA does not seem to offer health benefits , in the short term , regarding the prevention of atherosclerosis in humans .  CLA supplementation for 2 mon did not alter the blood cholesterol or lipoprotein levels of healthy , normolipidemic subjects . The supplementation did increase CLA in the plasma but only 4.23 % of the ingested CLA was present in the plasma at any given time . No adverse effect of CLA supplementation was detected in this study Conjugated linoleic acid ( CLA ) is shown to have chemoprotective properties in various experimental cancer models . CLA is easily oxidised and it has been suggested that an increased lipid oxidation may contribute to the antitumorigenic effects . This report investigates the urinary levels of 8‐iso‐PGF2α , a major isoprostane and 15‐keto‐dihydro‐PGF2α , a major metabolite of PGF2α , as indicators of non‐enzymatic and enzymatic lipid peroxidation after dietary supplementation of CLA in healthy human subjects for 3 months . A significant increase of both 8‐iso‐PGF2α and 15‐keto‐dihydro‐PGF2α in urine was observed after 3 months of daily CLA intake ( 4.2 g/day ) as compared to the control group ( P<0.0001 ) . Conjugated linoleic acid had no effect on the serum α‐tocopherol levels . However , γ‐tocopherol levels in the serum increased significantly ( P=0.015 ) in the CLA‐treated group . Thus , CLA may induce both non‐enzymatic and enzymatic lipid peroxidation in vivo . Further studies of the mechanism behind , and the possible consequences of , the increased lipid peroxidation after CLA supplementation are urgently needed BACKGROUND Animal studies have suggested that conjugated linoleic acid ( CLA ) , a natural component of ruminant meat and dairy products , may confer beneficial effects on health . However , little information on the effects of CLA on immune function is available , especially in humans . Furthermore , the effects of individual isomers of CLA have not been adequately investigated . OBJECTIVE This study investigated the effects of supplementing the diet with 3 doses of highly enriched cis-9,trans-11 CLA ( 0.59 , 1.19 , and 2.38 g/d ) or trans-10,cis-12 CLA ( 0.63 , 1.26 , and 2.52 g/d ) on immune outcomes in healthy humans . DESIGN The study had a r and omized , double-blind , crossover design . Healthy men consumed 1 , 2 , and 4 capsules sequentially that contained 80 % of either cis-9,trans-11 CLA or trans-10,cis-12 CLA for consecutive 8-wk periods . This regimen was followed by a 6-wk washout and a crossover to the other isomer . RESULTS Both CLA isomers decreased mitogen-induced T lymphocyte activation in a dose-dependent manner . There was a significant negative correlation between mitogen-induced T lymphocyte activation and the proportions of both cis-9,trans-11 CLA and trans-10,cis-12 CLA in peripheral blood mononuclear cell lipids . However , CLA did not affect lymphocyte sub population s or serum concentrations of C-reactive protein and did not have any consistent effects on ex vivo cytokine production . CONCLUSION CLA supplementation results in a dose-dependent reduction in the mitogen-induced activation of T lymphocytes . The effects of cis-9,trans-11 CLA and trans-10,cis-12 CLA were similar , and there was a negative correlation between mitogen-induced T lymphocyte activation and the cis-9,trans-11 CLA and trans-10,cis-12 CLA contents of mononuclear cells BACKGROUND Animal studies suggest that dietary cis-9,trans-11 ( c9,t11 ) conjugated linoleic acid ( CLA ) may inhibit or regress the development of atherosclerosis . The effect of CLA on atherosclerosis has not been assessed in humans . OBJECTIVE We investigated the effect of c9,t11 CLA supplementation on aortic pulse wave velocity ( a marker of atherosclerosis ) and on cardiovascular risk factors in overweight and obese but otherwise apparently healthy subjects . DESIGN In a double-blind , r and omized , placebo-controlled , parallel-group trial , we r and omly assigned 401 subjects , aged 40 - 70 y and with a body mass index ( in kg/m(2 ) ) > or = 25 , to receive either 4 g CLA/d ( 2.5 g c9,t11 CLA/d and 0.6 g trans-10,cis-12 CLA/d ) or placebo supplements for 6 mo . Aortic pulse wave velocity , blood pressure , anthropometric characteristics , and concentrations of fasting lipid , glucose , insulin , and C-reactive protein were measured before and after supplementation . RESULTS During the intervention , mean ( + /-SE ) pulse wave velocity did not change in the c9,t11 CLA group ( Delta0.00 + /- 0.07 ) compared with the placebo group ( Delta0.09 + /- 0.06 ) . There was no effect of c9,t11 CLA supplementation on blood pressure , body composition , insulin resistance , or concentrations of lipid , glucose , and C-reactive protein . CONCLUSION This study does not support an antiatherosclerotic effect or an effect on cardiovascular risk factors of c9,t11 CLA . This trial was registered at www . clinical trials.gov as NCT00706745 BACKGROUND Short-term trials showed that conjugated linoleic acid ( CLA ) may reduce body fat mass ( BFM ) and increase lean body mass ( LBM ) , but the long-term effect of CLA was not examined . OBJECTIVE The objective of the study was to ascertain the 1-y effect of CLA on body composition and safety in healthy overweight adults consuming an ad libitum diet . DESIGN Male and female volunteers ( n = 180 ) with body mass indexes ( in kg/m(2 ) ) of 25 - 30 were included in a double-blind , placebo-controlled study . Subjects were r and omly assigned to 3 groups : CLA-free fatty acid ( FFA ) , CLA-triacylglycerol , or placebo ( olive oil ) .  Change in BFM , as measured by dual-energy X-ray absorptiometry , was the primary outcome . Secondary outcomes included the effects of CLA on LBM , adverse events , and safety variables . RESULTS Mean ( + /- SD ) BFM in the CLA-triacylglycerol and CLA-FFA groups was 8.7 + /- 9.1 % and 6.9 + /- 9.1 % , respectively , lower than that in the placebo group ( P < 0.001 ) . Subjects receiving CLA-FFA had 1.8 + /- 4.3 % greater LBM than did subjects receiving placebo ( P = 0.002 ) . These changes were not associated with diet or exercise . LDL increased in the CLA-FFA group ( P = 0.008 ) , HDL decreased in the CLA-triacylglycerol group ( P = 0.003 ) , and lipoprotein(a ) increased in both CLA groups ( P < 0.001 ) compared with month 0 . Fasting blood glucose concentrations remained unchanged in all 3 groups . Glycated hemoglobin rose in all groups from month 0 concentrations , but there was no significant difference between groups . Adverse events did not differ significantly between groups . CONCLUSION Long-term supplementation with CLA-FFA or CLA-triacylglycerol reduces BFM in healthy overweight adults BACKGROUND Conjugated linoleic acid ( CLA ) is a supplemental dietary fatty acid that decreases fat mass accretion in young animals . OBJECTIVE The aim of this study was to determine CLA 's efficacy with regard to change in  fat and body mass index ( BMI ;  in kg/m(2 ) ) in children . DESIGN We conducted a 7 + /- 0.5-mo r and omized , double-blind , placebo-controlled trial of CLA in 62 prepubertal children aged 6 - 10 y who were overweight or obese but otherwise healthy . The subjects were r and omly assigned to receive 3 g/d of 80 % CLA ( 50:50 cis-9,trans-11 and trans-10,cis-12 isomers ) or placebo in chocolate milk . RESULTS Fifty-three subjects completed the trial ( n = 28 in the  CLA group , n = 25 in the  placebo group ) . CLA attenuated the increase in BMI ( 0.5 + /- 0.8 ) compared with placebo ( 1.1 + /- 1.1 ) ( P = 0.05 ) . The percentage change in body fat measured by dual-energy X-ray absorptiometry was smaller ( P = 0.001 ) in the CLA group ( -0.5 + /- 2.1 % ) than in the placebo group ( 1.3 + /- 1.8 % ) . The change in abdominal body fat as a percentage of total body weight was smaller ( P = 0.02 ) in the CLA group ( -0.09 + /- 0.9 % ) than in the placebo group ( 0.43 + /- 0.6 % ) . There were no significant changes in plasma glucose , insulin , or LDL cholesterol between groups . Plasma HDL cholesterol decreased significantly more ( P = 0.05 ) in the CLA group ( -5.1 + /- 7.3 mg/dL ) than in the placebo group ( -0.7 + /- 8 mg/dL ) . Bone mineral accretion was lower ( P = 0.04 ) in the CLA group ( 0.05 + /- 0.03 kg ) than in the placebo group ( 0.07 + /- 0.03 kg ) . Reported gastrointestinal symptoms did not differ significantly between groups . CONCLUSIONS CLA supplementation for 7 + /- 0.5 mo decreased body fatness in 6 - 10-y-old children who were overweight or obese but did not improve plasma lipids or glucose and decreased HDL more than in the placebo group . Long-term investigation of the safety and efficacy of CLA supplementation in children is recommended BACKGROUND & AIMS Metabolic effects of dietary fat quality in people with type 2 diabetes are not well-understood . The study objective was to evaluate effects of conjugated linoleic acid ( CLA ) and safflower ( SAF ) oils on glycemia , blood lipids , and inflammation . The hypothesis we tested is that dietary oils improve glycemia , lipids , and inflammatory markers in a time-dependent way that follows accumulation of linoleic acid and CLA isomers in serum of subjects supplemented with dietary oils . METHODS Fifty-five post-menopausal , obese women with type 2 diabetes enrolled , and 35 completed this r and omized , double-masked crossover study . Treatments were 8 g daily of CLA and SAF for 16 weeks each . We used a multiple testing procedure with pre-determined steps analysis to determine the earliest time that a significant effect was detected . RESULTS CLA did not alter measured metabolic parameters . SAF decreased HbA1c ( -0.64 ± 0.18 % , p = 0.0007 ) and C-reactive protein ( -13.6 ± 8.2 mg/L , p = 0.0472 ) , increased QUICKI ( 0.0077 ± 0.0035 , p = 0.0146 ) with a minimum time to effect observed 16 weeks after treatment . SAF increased HDL cholesterol ( 0.12 ± 0.05 mmol/L , p = 0.0228 ) with the minimum time to detect an effect of SAF at 12 weeks . The minimum time to detect an increase of c9t11-CLA , t10c12-CLA , and linoleic acid in serum of women supplemented CLA or SAF , respectively , was four weeks . CONCLUSIONS We conclude that 8 g of SAF daily improved glycemia , inflammation , and blood lipids , indicating that small changes in dietary fat quality may augment diabetes treatments to improve risk factors for diabetes-related complications
There was a significant heterogeneity for the impact of CLA  on CRP and IL-6 , but not TNF-α .
Conclusions This meta- analysis showed that CLA supplementation may increase inflammatory markers ( CRP and TNF-α ) .
Background / objectives Conjugated linoleic acid ( CLA ) is a polyunsaturated fatty acid with attractive biological activities .
Numerous studies have been conducted on the inflammation-lowering effects of CLA in in vitro and animal models .
However , the effects of CLA treatment on the inflammatory markers in humans are controversial .