No human benefit?! I'm curious what studies you've been reading. In terms of immediate fat loss, yeah of course it's not a vital supp, but the studies out do show prolonged benefit...in fact it's one of the only FEW supplements that most researchers would recommend.
I suppose if you feel it's working for you, then more power to ya'. But I've read too much that goes the other way. Here's a few things:
--Efficacy and safety of dietary supplements containing CLA for the treatment of obesity: evidence from animal and human studies.
Larsen TM, Toubro S, Astrup A.
Department of Human Nutrition, Center for Advanced Food Studies, The Royal Veterinary and Agricultural University, DK-1958 Frederiksberg C, Denmark.
Dietary supplements containing conjugated linoleic acid (CLA) are widely promoted as weight loss agents available over the counter and via the Internet. In this review, we evaluate the efficacy and safety of CLA supplementation based on peer-reviewed published results from randomized, placebo-controlled, human intervention trials lasting more than 4 weeks. We also review findings from experimental studies in animals and studies performed in vitro. CLA appears to produce loss of fat mass and increase of lean tissue mass in rodents, but the results from 13 randomized, controlled, short-term (<6 months) trials in humans find little evidence to support that CLA reduces body weight or promotes repartitioning of body fat and fat-free mass in man. However, there is increasing evidence from mice and human studies that the CLA isomer trans-10, cis-12 may produce liver hypertrophy and insulin resistance via a redistribution of fat deposition that resembles lipodystrophy. CLA also decreases the fat content of both human and bovine milk.
In conclusion, although CLA appears to attenuate increases in body weight and body fat in several animal models, CLA isomers sold as dietary supplements are not effective as weight loss agents in humans and may actually have adverse effects on human health.PMID: 12923219 [PubMed - in process]---
ANOTHER:
--Proc Nutr Soc. 2005 May;64(2):171-82.
The effects of conjugated linoleic acid on human health-related outcomes.
Tricon S, Burdge GC, Williams CM, Calder PC, Yaqoob P.
Hugh Sinclair Unit of Human Nutrition, School of Food Bioscienes, University of Reading, Whiteknights, UK. S.Tricon@reading.ac.uk
Conjugated linoleic acid (CLA) is a collective term for a mixture of positional and geometric isomers of conjugated dienoic derivatives of linoleic acid. CLA has received considerable attention as a result of animal experiments that report anti-carcinogenic, anti-atherogenic and anti-diabetic properties, and modulation of body composition and immune function. Several studies of CLA supplementation in human subjects have now been published, but in contrast to animal studies there has been marked variation between reports on the health-related outcomes.
The consensus from seventeen published studies in human subjects is that CLA does not affect body weight or body composition. Some detrimental effects of the trans-10,cis-12 CLA isomer have also been reported in terms of altered blood lipid composition and impaired insulin sensitivity. Finally, CLA has only limited effects on immune functions in man. However, there have been reports of some interesting isomer-specific effects of CLA on the blood lipid profile, but not on immune function. These isomer-specific effects need further investigation.
Until more is known, CLA supplementation in man should be considered with caution.PMID: 15960862 [PubMed - in process]
ANOTHER:
--Am J Clin Nutr. 2005 Aug;82(2):309-19. Related Articles, Links
Lack of effect of dietary conjugated linoleic acids naturally incorporated into butter on the lipid profile and body composition of overweight and obese men.
Desroches S, Chouinard PY, Galibois I, Corneau L, Delisle J, Lamarche B, Couture P, Bergeron N.
Institute on Nutraceuticals and Functional Foods and Animal Sciences, Laval University, Quebec, Canada.
BACKGROUND: Dietary conjugated linoleic acid (CLA) is known to reduce atherosclerosis, plasma total and LDL-cholesterol concentrations, and body fat accumulation in several animal species. Of the few studies that investigated the effects of CLA supplementation in humans, all used commercially formulated oral supplements made from a mixture of CLA isomers. OBJECTIVE: We compared the effects on plasma lipoproteins and body composition of the consumption of a modified butter naturally enriched with CLA (CLA-B: 4.22 g CLA/100 g butter fat) by the addition of sunflower oil to the diet of dairy cows with the consumption of a control butter (CON-B) that was low in CLA (0.38 g CLA/100 g butter fat). DESIGN: In a crossover design study including an 8-wk washout period, 16 men [x +/- SD age: 36.6 +/- 12.4 y; body mass index (in kg/m(2)): 31.2 +/- 4.4] were fed each of the 2 experimental isoenergetic diets, providing 15% of energy as protein, 45% as carbohydrates, and 40% as lipids, of which >60% was derived from experimental fats, for 4 wk. RESULTS: Consumption of the CLA-B diet induced a significantly (P < 0.05) smaller reduction in plasma total cholesterol and in the ratio of total to HDL cholesterol (-0.02 mmol/L and -0.00, respectively) than did consumption of the CON-B diet (-0.26 mmol/L and-0.34, respectively). Abdominal adipose tissue area measured by computed tomography showed no difference in accumulation of either visceral or subcutaneous adipose tissue after the 2 experimental diets.
CONCLUSION: These results suggest that a 10-fold CLA enrichment of butter fat does not induce beneficial metabolic effects in overweight or obese men.Also, these were quotes by Lyle McDonald I used in another post about CLA:
"Time to come to terms with it, if you haven't already: add CLA to the list of stuff that works great on rats/mice and does jack crap for humans".
Also from Lyle--- "If CLA does anything in humans it will likely have to be mega-dosed to achieve anything even approximating what occurs in mice/rats (who respond between 3-7 times better than humans because of a difference in metabolic rate). So you either have to take 3-7 times as much (at a monstrous cost) or wait 3-7 times as long for the effects to become noticeable."
Personally, I've taken CLA at up to 10 grams a day (very expensive), and noticed no better body composition changes than when I wasn't taking it. FWIW, anyways.....