CLA causes insulin RESISTANCE

[goose]

This study was just published, in a very pristigious journal, and was performed in human subjects:


Circulation 2002 Oct 8;106(15):1925-9 Related Articles, Links

Supplementation with conjugated linoleic acid causes isomer-dependent oxidative stress and elevated C-reactive protein: a potential link to fatty acid-induced insulin resistance.

Riserus U, Basu S, Jovinge S, Fredrikson GN, Arnlov J, Vessby B.

Department of Public Health and Caring Sciences/Geriatrics, Uppsala University, Uppsala, Sweden. [email protected]

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 t10c12 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 randomized to one of 3 groups receiving t10c12 CLA, a CLA mixture, or placebo for 12 weeks. Insulin sensitivity (euglycemic clamp), serum lipids, in vivo lipid peroxidation (determined as urinary 8-iso-PGF(2alpha) [F2-isoprostanes]), 15-ketodihydro PGF(2alpha), plasma vitamin E, plasma C-reactive protein, tumor necrosis factor-alpha, and interleukin-6 were assessed before and after treatment. Supplementation with t10c12 CLA markedly increased 8-iso-PGF(2alpha) (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-PGF(2alpha), 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: t10c12 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 t10c12 CLA might be of clinical importance with regard to cardiovascular disease, in consideration of the widespread use of dietary supplements containing this fatty acid.


goose4..

[Pinnacle]

In OBESE men(who are at risk already).



NEXT......

[oldman]

English pretty please.

I use CLa dn have for years.. I honestly thank you for the info you posted but i am not smart enough to understand what it is saying.

thanks


Oldman

[abstrack]

I have read that before, but it is only one study and there is a plethora of other studies that will deebate it. I use to go round and round with the people over at Pure Fitness on this.

[powerliftmike]

Conjugated linoleic acid and atherosclerosis in rabbits.

Lee KN, Kritchevsky D, Pariza MW.

Department of Food Microbiology and Toxicology, University of Wisconsin-Madison 53706.

Conjugated linoleic acid (CLA) consists of a series of positional and geometric dienoic isomers of linoleic acid that occur naturally in foods. CLA exhibits antioxidant activity in vitro and in vivo. To assess the effect of CLA on atherosclerosis, 12 rabbits were fed a semi-synthetic diet containing 14% fat and 0.1% cholesterol for 22 weeks. For 6 of these rabbits, the diet was augmented with CLA (0.5 g CLA/rabbit per day). Blood samples were taken monthly for lipid analysis. By 12 weeks total and LDL cholesterol and triglycerides were markedly lower in the CLA-fed group. Interestingly, the LDL cholesterol to HDL cholesterol ratio and total cholesterol to HDL cholesterol ratio were significantly reduced in CLA-fed rabbits. Examination of the aortas of CLA-fed rabbits showed less atherosclerosis.

Feeding conjugated linoleic acid to animals partially overcomes catabolic responses due to endotoxin injection.

Miller CC, Park Y, Pariza MW, Cook ME.

Poultry Science Dept., U.W. Madison 53706.

The ability of conjugated linoleic acid to prevent endotoxin-induced growth suppression was examined. Mice fed a basal diet or diet with 0.5% fish oil lost twice as much body weight after endotoxin injection than mice fed conjugated linoleic acid. By 72 hours post injection, mice fed conjugated linoleic acid had body weights similar to vehicle injected controls; however, body weights of basal and fish oil fed mice injected with endotoxin were reduced. Conjugated linoleic acid prevented anorexia from endotoxin injection. Splenocyte blastogenesis was increased by conjugated linoleic acid.

Conjugated linoleic acid rapidly reduces body fat content in mice without affecting energy intake
James P. DeLany1,2, Fawn Blohm1, Alycia A. Truett1, Joseph A. Scimeca3, and David B. West1,2

1 Pennington Biomedical Research Center, Louisiana State University, Baton Rouge 70808; 2 Department of Physiology, Louisiana State University Medical School, New Orleans, Louisiana 70112; and 3 Kraft Foods, Glenview, Illinois 60025

Results:
There was a significant main effect of CLA on body weight (P < 0.05), an effect of CLA over time (P < 0.01), and a significant interaction between the two (P < 0.01; Fig. 1). When compared with the controls, body weight was significantly lower at day 18 in the 0.75% CLA group and day 21 in the 1.0% CLA group (P < 0.05) and remained lower throughout the remainder of the study. Energy intake was not significantly different from control except in the 0.25% CLA group, which was slightly increased relative to the control diet and other CLA doses (P < 0.05; Fig. 2).

Conjugated Linoleic Acid Reduces Body Fat Mass in Overweight and Obese Humans1
Henrietta Blankson, Jacob A. Stakkestad*, Hans Fagertun{dagger}, Erling Thom**, Jan Wadstein{ddagger} and Ola Gudmundsen2

Scandinavian Clinical Research AS, N-2027 Kjeller, Norway; ** Parexel Medstat AS, Lillestrøm, Norway; {dagger} Scandinavian Statistical Services AS, N-2027 Kjeller, Norway; * Cecor AS, Haugesund, Norway; and {ddagger} Natural AS, Oslo, Norway

Conjugated linoleic acid (CLA) has been shown to reduce body fat mass (BFM) in animals. To investigate the dose-response relationships of conjugated linoleic acid with regard to BFM in humans, a randomized, double-blind study including 60 overweight or obese volunteers (body mass index 25–35 kg/m2) was performed. The subjects were divided into five groups receiving placebo (9 g olive oil), 1.7, 3.4, 5.1 or 6.8 g conjugated linoleic acid per day for 12 wk, respectively. Dual-energy X-ray absorptiometry was used to measure body composition [measurements at wk 0 (baseline), 6 and 12]. Of the 60 subjects, 47 completed the study. Eight subjects withdrew from the study due to adverse events; however, no differences among treatment groups were found regarding adverse events. Repeated-measures analysis showed that a significantly higher reduction in BFM was found in the conjugated linoleic acid groups compared with the placebo group (P = 0.03). The reduction of body fat within the groups was significant for the 3.4 and 6.8 g CLA groups (P = 0.05 and P = 0.02, respectively). No significant differences among the groups were observed in lean body mass, body mass index, blood safety variables or blood lipids. The data suggest that conjugated linoleic acid may reduce BFM in humans and that no additional effect on BFM is achieved with doses > 3.4 g CLA/d.

Conjugated linoleic acid. A powerful anticarcinogen from animal fat sources.

Ip C, Scimeca JA, Thompson HJ.

Department of Surgical Oncology, Roswell Park Cancer Institute, Buffalo, New York 14263.

Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of linoleic acid, which is found preferentially in dairy products and meat. Preliminary studies indicate that CLA is a powerful anticarcinogen in the rat mammary tumor model with an effective range of 0.1-1% in the diet. This protective effect of CLA is noted even when exposure is limited to the time of weaning to carcinogen administration. The timing of this treatment corresponds to maturation of the mammary gland to the adult stage, suggesting that CLA may have a direct effect in reducing the cancer risk of the target organ. Of the vast number of naturally occurring substances that have been demonstrated to have anticarcinogenic activity in experimental models, all but a handful of them are of plant origin. Conjugated linoleic acid is unique because it is present in food from animal sources, and its anticancer efficacy is expressed at concentrations close to human consumption levels.

Just throwing some studies on CLA out there for you. Sounds pretty good to me, although only one was done in humans.