Obesity Discussion Forums

[Obesity Discussion]

Don't Fear The Scale After Holidays: Study Shows CLA Effective When Adults Are Susceptible To Weight And Fat Gain


A scientific study published today offers consumers new hope that they can avoid weight and fat gain during the infamous "food holidays" in November and December, as well as the gains that come with the normal aging process.

A study in the prestigious International Journal of Obesity suggests that conjugated linoleic acid (CLA), a naturally occurring fatty acid, could have long-term health benefits by preventing common weight and fat gain attributable to overeating and aging. These findings are consistent with past scientific trials of the popular dietary supplement.

Prof. Dale Schoeller, Ph.D., University of Wisconsin-Madison and a principal author of the study published today, recognized that "small, often cumulative weight gains during the holiday season contribute to 'weight creep' during adulthood." He sought to determine if CLA would help overweight adults reduce body fat and prevent weight gain during a six-month period that included the holiday season.

The dramatic findings showed that participants taking CLA supplements did reduce body fat by 2.2 pounds and their body weight by 1.3 pounds. In comparison, those in the placebo group gained 1.5 pounds of body fat and 2.4 pounds of body weight during the test period.

"These findings suggest that CLA may serve a critical role in reducing the cumulative weight and fat gain that occurs with age," Schoeller said. "About 65 percent of the U.S. population is obese or overweight -- that's a dangerous trend on many levels. We need more research like this to help overweight individuals when they are susceptible to weight gain."

The UW study involved 40 healthy, overweight men and women who took 3.2 grams of CLA or a placebo daily from August 2004 to March 2005. Participants followed "healthy lifestyle" advice, were not restricted by a controlled diet, and participated in moderate physical activity.

Researchers conducting the double-blind, randomized, placebo-controlled study concluded that CLA supplementation is safe and well-tolerated.

Past studies have found that taking CLA decreases body fat mass, maintains lean body mass, and aids weight management-reducing the "yo yo" effect often associated with diet plans. A 12-month study published in late 2005 by the Journal of Nutrition found that adults taking a CLA supplement lost as much as 9 percent of their body fat. As important, a follow-up 12-month study found that participants did not regain their body fat.

CLA is naturally found in dairy and meat from ruminant animals. But, because cattle are increasingly grain-fed, instead of grass-fed, and due to changes in consumer dietary habits, it's very difficult to obtain an optimal level of CLA without supplementation. To get three grams of CLA through food alone, an adult would have to consume more than four gallons of ice cream or 28 quarter-pound hamburgers every day.

CLA lowers the amount of fat normally stored after meals, helping the body to break down and use fat. Supplementation with CLA is most effective as part of a daily regimen that includes exercise and a reasonable diet.

CLA is stimulant-free and is available in health food stores, retail chains and online.



About Tonalin(R) CLA

Tonalin(R) CLA is the original brand of CLA and is an exclusively licensed product of Cognis. CLA is a polyunsaturated, conjugated fatty acid. Cognis produces Tonalin(R) CLA through a proprietary process that converts linoleic acid from safflowers into CLA, providing the highest quality of CLA available. Tonalin(R) CLA contains the lowest amount of non-naturally occurring isomers, a patent-protected attribute offering food and dietary supplement manufacturers the highest levels of ingredients known to be beneficial.

CLA and Obesity

[Irving]

good results but I digress, is the sample size of 40 a bit small?

[Obesity Discussion]

Originally Posted by Irving

good results but I digress, is the sample size of 40 a bit small?

Agreed, and because of that I did a little searching and look what I found




Conjugated linoleic acid and human health: a critical evaluation of the evidence.

Tricon S, Yaqoob P.

Hugh Sinclair Unit of Human Nutrition, School of Food Biosciences, University of Reading, Reading, UK.

PURPOSE OF REVIEW: This review critically evaluates studies investigating the effects of conjugated linoleic acid on human health, including effects on body composition, blood lipids, liver metabolism, insulin sensitivity and immune function. It focuses mainly on human intervention studies, but includes some reference to animal and cellular studies which provide insight into potential molecular mechanisms of action of conjugated linoleic acid. RECENT FINDINGS: Human studies continue to report inconsistent effects of conjugated linoleic acid on human health. Some of these reports are based on overinterpretation of marginal effects of supplementation. Recent data suggest that the effects of the substance may be isomer dependent and that cis-9,trans-11 and trans-10,cis-12 conjugated linoleic acids have opposing effects on blood lipids and on metabolism in adipocytes and hepatic cells. SUMMARY: Claims that conjugated linoleic acid is beneficial for health remain as yet unconvincing. Human studies investigating the effects of conjugated linoleic acid supplements have tended to use mixtures of isomers and have been inconsistent. More recent studies have attempted to use relatively pure preparations of single isomers and these studies suggest that the effects of conjugated linoleic acid may be isomer-specific. These recent data suggest a relative detrimental effect of trans-10,cis-12 conjugated linoleic acid on blood lipids. There appears to be little effect of conjugated linoleic acid on immune function and the effects on insulin sensitivity remain unclear.

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Arterioscler Thromb Vasc Biol. 2006 Feb;26(2):307-12. Epub 2005 Dec 8. Related Articles, Links

Conjugated linoleic acid impairs endothelial function.

Taylor JS, Williams SR, Rhys R, James P, Frenneaux MP.

Morriston Hospital, Swansea, UK. jswt@totalise.co.uk

OBJECTIVE: To determine the effect of dietary supplementation with conjugated linoleic acid (CLA) on body mass index (BMI), body fat distribution, endothelial function, and markers of cardiovascular risk. METHODS AND RESULTS: Forty healthy volunteers with BMI >27 kg/m2 were randomized to receive a CLA isomeric mixture or olive oil in a 12-week double-blind study. Subcutaneous body fat and abdominal/hepatic fat content were assessed using skin-fold thicknesses and computed tomography scanning, respectively. Endothelial function was assessed by brachial artery flow-mediated dilatation (FMD). Plasma isoprostanes were measured as an index of oxidative stress. CLA supplementation did not result in a significant change in BMI index or total body fat. There was a significant decrease in limb (-7.8 mm, P<0.001), but not torso skin-fold thicknesses or abdominal or liver fat content. Brachial artery FMD declined (-1.3%, P=0.013), and plasma F2-isoprostanes increased (+91 pg/mL, P=0.042). CONCLUSIONS: A CLA isomeric mixture had at most modest effects on adiposity and worsened endothelial function. On the basis of these results, the use of the isomeric mixture of CLA as an aid to weight loss cannot be recommended.

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Riserus U, Vessby B, Arnlov J, Basu S.
Effects of cis-9,trans-11 conjugated linoleic acid supplementation on insulin sensitivity, lipid peroxidation, and proinflammatory markers in obese men.
Am J Clin Nutr. 2004 Aug;80(2):279-83.

BACKGROUND: We recently showed that trans-10,cis-12 (t10,c12) conjugated linoleic acid (CLA) causes insulin resistance in obese men. However, metabolic effects of the c9,t11 CLA isomer are still unknown in obese men. Because c9,t11 CLA is the predominant CLA isomer in foods and is included in dietary weight-loss products, it is important to conduct randomized controlled studies that use c9,t11 CLA preparations. ...

In a randomized, double-blind, placebo-controlled study, 25 abdominally obese men received 3 g c9,t11 CLA/d or placebo (olive oil). Before and after 3 mo of supplementation, we assessed insulin sensitivity (hyperinsulinemic euglycemic clamp), lipid metabolism, body composition, and urinary 8-iso-prostaglandin F(2alpha) (a major F(2)-isoprostane) and 15-keto-dihydro-prostaglandin F(2alpha), markers of in vivo oxidative stress and inflammation, respectively.

RESULTS: ... Compared with placebo, c9,t11 CLA decreased insulin sensitivity by 15% (P < 0.05) and increased 8-iso-prostaglandin F(2alpha) and 15-keto-dihydro-prostaglandin F(2alpha) excretion by 50% (P < 0.01) and 15% (P < 0.05), respectively. The decreased insulin sensitivity was independent of changes in serum lipids, glycemia, body mass index, and body fat but was abolished after adjustment for changes in 8-iso-prostaglandin F(2alpha) concentrations. There were no differences between groups in body composition. CONCLUSIONS: A CLA preparation containing the purified c9,t11 CLA isomer increased insulin resistance and lipid peroxidation compared with placebo in obese men. Because c9,t11 CLA occurs in commercial supplements as well as in the diet, the present results should be confirmed in larger studies that also include women.

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Riserus U, Basu S, Jovinge S, Fredrikson GN, Arnlov J, Vessby B.
Supplementation with conjugated linoleic acid causes isomer-dependent oxidative stress and elevated C-reactive protein: a potential link to fatty acid-induced insulin resistance.
Circulation. 2002 Oct 8;106(15):1925-9.

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.

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Larsen TM, Toubro S, Astrup A.
Efficacy and safety of dietary supplements containing CLA for the treatment of obesity: evidence from animal and human studies.
J Lipid Res. 2003 Dec;44(12):2234-41.

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. ...

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.

[William Wallace]

Interesting to see both sides, however it would have been nicer to see larger sample sizes in both studies.

[Merle]

Good stuff to know, sounds like more research needs to be done before anyone draws conclusions on this weight loss supplement.