Question:

Will taking conjugated linoleic acid decrease your belly size and leg size?

I recently heard on the Dr. Oz show that taking conjugated linoleic acid will decrease your belly size and leg size. I have a great deal of respect for Bryce Wylde and his knowledge and thought I would ask the real experts.

I am more concerned about losing weight on my legs. I do pilates about 3 times a week and am now eating very healthfully. Please advise.
Photo of Bryce Wylde
A double-blind trial found that exercising individuals taking 1,800 mg per day of conjugated linoleic acid (CLA) lost more body fat after 12 weeks than did a similar group taking a placebo. However, two other studies found that amounts of CLA from 0.7 to 3.0 grams per day did not affect body composition.2, 3 Most double-blind trials have found that larger amounts of CLA, 3.2 to 4.2 grams per day, do reduce body fat; however, one double-blind study of experienced strength-training athletes reported no effect of 6 grams per day of CLA on body fat, muscle mass, or strength improvement. Jury's still out.


References

1. Thom E, Wadstein J, Gudmundsen O. Conjugated linoleic acid reduces body fat in healthy exercising humans. J Int Med Res 2001;29:392–6.

2. Mougios V, Matsakas A, Petridou A, et al. Effect of supplementation with conjugated linoleic acid on human serum lipids and body fat. J Nutr Biochem 2001;12:585–94.

3. Zambell KL, Keim NL, Van Loan MD, et al. Conjugated linoleic acid supplementation in humans: effects on body composition and energy expenditure. Lipids 2000;35:777–82.

4. Riserus U, Berglund L, Vessby B. Conjugated linoleic acid (CLA) reduced abdominal adipose tissue in obese middle-aged men with signs of the metabolic syndrome: a randomised controlled trial. Int J Obes Relat Metab Disord 2001;25:1129–35.

5. Smedman A, Vessby B. Conjugated linoleic acid supplementation in humans–metabolic effects. Lipids 2001;36:773-81.

6. Blankson H, Stakkestad JA, Fagertun H, et al. Conjugated linoleic acid reduces body fat mass in overweight and obese humans. J Nutr 2000;130:2943–8.

7. Whigham LD, Watras AC, Schoeller DA. Efficacy of conjugated linoleic acid for reducing fat mass: a meta-analysis in humans. Am J Clin Nutr 2007;85:1203–11.

8. Kreider RB, Ferreira MP, Greenwood M, et al. Effects of conjugated linoleic acid supplementation during resistance training on body composition, bone density, strength, and selected hematological markers. J Strength Cond Res 2002;16:325–34.

9. Cesano A, Visonneau S, Scimeca JA, et al. Opposite effects of linoleic acid and conjugated linoleic acid on human prostatic cancer in SCID mice. Anticancer Res 1998;18:1429-34.

10. Thompson H, Zhu Z, Banni S, et al. Morphological and biochemical status of the mammary gland as influenced by conjugated linoleic acid: implication for a reduction in mammary cancer risk. Cancer Res 1997;57:5067-72.

11. Ip C. Review of the effects of trans fatty acids, oleic acid, n-3 polyunsaturated fatty acids, and conjugated linoleic acid on mammary carcinogenesis in animals. Am J Clin Nutr 1997;66(suppl):1523S-29S [review].

12. Parodi PW. Cows’ milk fat components as potential anticarcinogenic agents. J Nutr 1997;127:1055-60 [review].

13. Cesano A, Visonneau S, Scimeca JA, et al. Opposite effects of linoleic acid and conjugated linoleic acid on human prostatic cancer in SCID mice. Anticancer Res 1998;18:1429-34.

14. Thompson H, Zhu Z, Banni S, et al. Morphological and biochemical status of the mammary gland as influenced by conjugated linoleic acid: implication for a reduction in mammary cancer risk. Cancer Res 1997;57:5067-72.

15. Ip C. Review of the effects of trans fatty acids, oleic acid, n-3 polyunsaturated fatty acids, and conjugated linoleic acid on mammary carcinogenesis in animals. Am J Clin Nutr 1997;66(suppl):1523S-29S [review].

16. Parodi PW. Cows’ milk fat components as potential anticarcinogenic agents. J Nutr 1997;127:1055-60 [review].

17. Larsson SC, Bergkvist L, Wolk A. High-fat dairy food and conjugated linoleic acid intakes in relation to colorectal cancer incidence in the Swedish Mammography Cohort. Am J Clin Nutr 2005;82:894–900.

18. Cesano A, Visonneau S, Scimeca JA, et al. Opposite effects of linoleic acid and conjugated linoleic acid on human prostatic cancer in SCID mice. Anticancer Res 1998;18:1429-34.

19. Thompson H, Zhu Z, Banni S, et al. Morphological and biochemical status of the mammary gland as influenced by conjugated linoleic acid: implication for a reduction in mammary cancer risk. Cancer Res 1997;57:5067-72.

20. Ip C. Review of the effects of trans fatty acids, oleic acid, n-3 polyunsaturated fatty acids, and conjugated linoleic acid on mammary carcinogenesis in animals. Am J Clin Nutr 1997;66(suppl):1523S-29S [review].

21. Parodi PW. Cows’ milk fat components as potential anticarcinogenic agents. J Nutr 1997;127:1055-60 [review].

22. Cesano A, Visonneau S, Scimeca JA, et al. Opposite effects of linoleic acid and conjugated linoleic acid on human prostatic cancer in SCID mice. Anticancer Res 1998;18:1429-34.

23. Thompson H, Zhu Z, Banni S, et al. Morphological and biochemical status of the mammary gland as influenced by conjugated linoleic acid: implication for a reduction in mammary cancer risk. Cancer Res 1997;57:5067-72.

24. Ip C. Review of the effects of trans fatty acids, oleic acid, n-3 polyunsaturated fatty acids, and conjugated linoleic acid on mammary carcinogenesis in animals. Am J Clin Nutr 1997;66(suppl):1523S-29S [review].

25. Parodi PW. Cows’ milk fat components as potential anticarcinogenic agents. J Nutr 1997;127:1055-60 [review].

26. Herbel BK, McGuire MK, McGuire MA, et al. Safflower oil consumption does not increase plasma conjugated linoleic acid concentrations in humans. Am J Clin Nutr 1998;67:332–7.

27. Gaullier JM, Halse J, Hoye K, et al. Conjugated linoleic acid supplementation for 1 y reduces body fat mass in healthy overweight humans. Am J Clin Nutr 2004;79:1118–25.

28. Smedman A, Basu S, Jovinge S, Fredrikson GN, Vessby B. Conjugated linoleic acid increased C-reactive protein in human subjects. Br J Nutr 2005;94:791–5.

29. Taylor JS, Williams SR, Rhys R, et al. Conjugated linoleic acid impairs endothelial function. Arterioscler Thromb Vasc Biol 2006;26:307–12.

30. Moloney F, Yeow TP, Mullen A, et al. Conjugated linoleic acid supplementation, insulin sensitivity, and lipoprotein metabolism in patients with type 2 diabetes mellitus. Am J Clin Nutr 2004;80:887-95.

31. 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;80:279–83.

32. Whigham LD, O'Shea M, Mohede IC, et al. Safety profile of conjugated linoleic acid in a 12-month trial in obese humans. Food Chem Toxicol 2004 Oct;42(10):1701–9.

33. Eyjolfson V, Spriet LL, Dyck DJ. Conjugated linoleic acid improves insulin sensitivity in young, sedentary humans. Med Sci Sports Exerc 2004;36:814–20.

34. Thom E. A pilot study with the aim of studying the efficacy and tolerability of Tonalin CLA on the body composition in humans. Lillestrom, Norway: Medstat Research Ltd., July 1997 [unpublished].
Response by Bryce Wylde B.Sc. Hons., DHMHS
Photo of Kirk Sutton
Before starting any new health program or before you begin taking any dietary supplement, always check with your primary health care provider.

CLA (Conjugated Linoleic Acid) is a dietary supplement that has been shown in clinical studies to reduce body fat and increase lean muscle. While reducing unwanted body fat, this dietary supplement also hinders “lipoprotein lipase,” which is an enzyme that is generally known for breaking down fat cells in food, which results in less fat being absorbed into the body. For effective weight loss 3.4g to 6g of CLA daily is recommended.

There are a few possible side affects, such as diarrhea and or upset stomach. Like many other dietary supplements, CLA is to be used in combination with a healthy, well balanced diet and a regular exercise routine, such as 2-3 prescribed resistance training programs per week.
Response by Kirk Sutton
Photo of Bruce Krahn
CLA has been shown to reduce abdominal body fat. In a study published in the International Journal of Obesity, there was an average reduction of one inch to the waistlines of 25 men over a four week study period. The cause of action is unknown but CLA appears to increase metabolic rate and improve glucose tolerance (this is probably why it seems to target the waist as this is an insulin related fat storage site). There have been no studies showing that CLA targets the legs specifically however fat loss tends to be systemic in nature and you may lose fat from your legs as well. Some research indicates that fat storage on the thigh and buttock areas is related to high estrogen levels so it may be prudent to have a hormone screening done by your naturopath. I would strongly recommend that you begin a strength training program as this will improve insulin management and increase metabolism better than pilates alone.
Response by Bruce Krahn

Disclaimer:

Before starting any new health program or before you begin taking any medication, natural medicine, or supplement, always check with your primary health care provider.

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