Conjugated Linoleic Acid

(conjugated linoleic acid)

Nonessential Micronutrient

OVERVIEW

Summary

Often overlooked as a performance-enhancing supplement and recently touted as one of the most underrated supplements on the market, CLA might be worth taking a second look at. Over two decades of research have shown CLA may significantly help reduce bodyfat, and there’s recent evidence to support that it increases muscle tissue. Primarily, though, it’s a powerful antioxidant, which appears to attribute to its convincing cancer-fighting potential.

Other names for CLA

conjugated linoleic acid

Where to find CLA

CLA is found in a variety of foods but is most concentrated in beef, turkey, and dairy products.

PERFORMANCE BENEFITS

Why athletes use CLA

Athletes and people who are weight conscious have begun supplementing with CLA because it’s been shown in research to significantly shift body composition in favor of fat loss and muscle gain. In addition, it’s being watched closely as a potentially potent cancer fighter and has, in fact, been shown in 313 animal and test-tube studies to help reduce the risk of certain cancers, including those of the breast, prostate, lung, skin, and stomach.

Ways that CLA can enhance Muscle Gain & Recovery:
  • Increase muscle tissue by assisting protein metabolism
  • Prevent muscle breakdown by reducing the negative effects of the body’s stress hormones
Ways that CLA can enhance Fat Loss:
  • Reduce bodyfat by suppressing enzymes that enlarge fat cells

HEALTH BENEFITS

Signs of CLA deficiency

No deficiency conditions are known to exist.

Potential uses for CLA

Research indicates that CLA may be useful in the treatment of:

  • Obesity
  • Catabolism (muscle wasting)
  • Cancer
  • Atherosclerosis
  • Cardiovascular disease

DISCUSSION

More about CLA

CLA (an acronym for conjugated linoleic acid) is considered a nonessential fatty acid. Although closely related to the omega-6 fatty acids (linoleic acid), it has significantly different mechanisms of action in the body. While CLA has been shown in numerous studies to reduce bodyfat and increase muscle growth, its popularity with athletes and fitness buffs has been modest at best. But because it has become so widely popular with individuals seeking optimal health and for its possible anti-carcinogenic effects (cancer prevention in certain parts of the body), the active crowd is now giving it a “second look.”

Evolution of research on CLA

In years past, CLA was given to livestock to help block the negative muscle-wasting effects of their bodies’ stress hormones, which would then lead to “beefier” animals. The scientists who first discovered CLA’s muscle-preserving properties have received patents for this use.

More recent studies on CLA indicate it has similar effects on humans. The first double-blind, placebo-controlled human study showed that after 28 days of supplementation, the CLA group increased their strength by almost 30 lbs in lifts compared to only 9.5 lbs in the placebo group. Blood tests also showed increased chemical markers (the ratio between blood urea nitrogen and creatine) for muscle-tissue-building effects in the CLA group.

Another supportive study, conducted by Thom Erling, Ph.D., measured subjects’ bodyfat and bodyweight over a three-month period. In this double-blind, placebo-controlled study, the first group took CLA at breakfast, lunch, and dinner. The second group took a placebo. At the end of three months, the CLA group lost an average of five pounds, which was not considered statistically significant. But, their bodyfat dropped by an impressive 15 to 20% compared to the placebo group who experienced little change.

Recently, Ola Gudmundsen, managing director of Scandinavian Clinical Research, presented a study that suggests CLA could help people lose weight, primarily by reducing overall fat mass. In this groundbreaking study, 60 overweight people who were not allowed to diet were randomly assigned to take either a 9-gram placebo of olive oil or 1.7 grams, 3.4 grams, 5.1 grams, or 6.8 grams of CLA daily for 12 weeks. Their bodyfat composition was measured at the start, middle, and end of the study. “We saw that they had a significant reduction in weight in the CLA group,” says Gudmundsen, “…about 2.2 lbs in 12 weeks.” Even more promising, the researchers found that this loss was overwhelmingly from bodyfat and didn’t affect overall weight or body mass index.

While it’s difficult to lose fat while gaining muscle, it can be done. Especially with the help of CLA — at least according to the most recent research. In this long-term study, people using CLA lost nine percent of their bodyfat while increasing lean body mass by two percent. This study also confirmed CLA’s safety over the long term.

In addition, other researchers have discovered that CLA has very positive effects on adults with diabetes. In this study, most participants who supplemented with CLA experienced a fivefold drop in blood sugar levels (fasting) while losing an average of 3.5 lbs (compared to the non-CLA group, which had no changes in bodyweight).

The findings from these human studies suggest CLA supplementation may offer tremendous benefits for athletes and those seeking body-composition changes; namely, fat loss and muscle gains.

How it works

When leading CLA researcher Michael W. Pariza from the University of Wisconsin-Madison was asked, “How does CLA work?” he cautiously replied, “In a general sense, what it’s doing is keeping little fat cells from getting big… perhaps by blocking certain enzymes that let fat cells swell.”

Although researches aren’t completely certain “how” CLA helps preserve muscle and decrease fat, they have several theories. Some researchers believe CLA has a balancing effect on substances called cytokines and prostaglandins. By bringing these substances into a healthy balance, CLA may optimize muscle growth and fat loss. Another theory maintains that CLA is directly involved in fat metabolism, so it helps the body preferentially burn fat. Still another theory holds that CLA counteracts the negative effects of corticosteroids, which are substances that break down muscle protein and increase fat gain.

Also recently, researchers have suggested that CLA’s body-composition-altering effects are likely due to its ability to regulate the metabolism of fat through a fairly complex process having to do with our body’s enzymes (namely, lipoprotein lipase and hormone-sensitive lipase). In one recent study, researchers found that the isomers t10,c12 in CLA appear to influence the bodyfat changes many people enjoy when supplementing with CLA. The long and short of it is that CLA appears to block fat uptake and then increase the speed of fat burning.

The understanding of CLA’s potential anti-carcinogenic effects is even less clear. It does appear that CLA is a potent antioxidant — likely even more powerful than the popular free-radical fighters Vitamin E and beta-carotene. Researchers suggest that CLA may suppress levels of “arachidonic acid,” which is known to produce inflammatory compounds that appear to encourage cancer growth.

Although the mechanisms by which CLA exerts its anti-cancer properties are not yet fully understood, it appears to be clear that, in some cases, CLA directly interacts with carcinogens to reduce their potency. The anti-cancer research on CLA, while abundant, is still in its infancy; therefore, CLA is likely to continue showing up in the scientific journals and mass media alike.

Other research has shown CLA may help prevent heart disease by helping reduce the risk of hardening of the arteries and raising good cholesterol levels while lowering elevated blood fat (triglyceride) levels. There’s even research that demonstrates CLA’s ability to normalize impaired glucose tolerance and improve insulin response, allowing for proper disposal of insulin. An unfortunate but common metabolic complication in the U.S., insulin resistance leads to type-2 diabetes, obesity, high blood pressure, lipid disorders, and many other unfavorable health conditions.

In conclusion

While the mechanisms behind CLA may not be clear, the studies indicate that it clearly does exert powerful effects on fat reduction and muscle building. These claims are further validated by numerous individuals — both in the gym and those living life to the fullest — who report impressive results from this life-enhancing supplement. If you’re looking for a way to increase your lean body mass while losing bodyfat, CLA may prove to be one of your most underrated yet powerful allies.

NOTES ON USAGE

Amount and Timing

Most researchers agree 3,000 mg (3 grams) divided into 3 dosages per day with meals is necessary for fat reduction.

Three thousand milligrams to 6,000 mg (3 to 6 grams) divided into 3 dosages per day with meals has been shown in recent studies to help induce muscle-tissue growth.

While CLA’s possible anti-carcinogenic effects have been studied only in animal and test-tube research, three 1,000-mg (1 gram) doses per day with meals are believed by many experts to potentially lower the risk of this disease.

Synergists of CLA

In animal studies, the combination of CLA with guarana was shown to reduce fat cells by an incredible 50%.

Toxicity of CLA

No known toxicity.

Bans and restrictions

None reported.

RELATED RESEARCH

  • Adlof, R.O., et al., “Biosynthesis of Conjugated Linoleic Acid in Humans,” Lipids 35.2 (2000) : 131-5.
  • Blankson, H., et al., “Conjugated Linoleic Acid Reduces Body Fat Mass in Overweight and Obese Humans,”J Nutr 130.12 (2000) : 2943-8.
  • Belury, M.A., et al., “The Conjugated Linoleic Acid (CLA) Isomer, t10c12-CLA, Is Inversely Associated with Changes in Body Weight and Serum Leptin in Subjects with Type 2 Diabetes Mellitus,” J Nutr 133.1 (2003) : 257S-60S.
  • Erling, T., “A Pilot Study with the Aim of Studying the Efficacy and Tolerability of CLA (Tonalin) on the Body Composition in Humans” (Medstat Research Ltd., Liilestrom, Norway, 1997).
  • Ferreira, M., Kreider, R., et al., “Effects of CLA Supplementation During Resistance Training on Body Composition and Strength,” J Strength Cond Res 11.4 (1998) : 280.
  • Gaullier, “Efficacy and Safety of One-Year Supplementation with Conjugated Linoleic Acid in Moderate Overweight,” AOCS Annual Meeting, 2003.
  • Kreider, R., et al., “Effect of Conjugated Linoleic Acid (CLA) Supplementation During Resistance-Training on Bone Mineral Content, Bone Mineral Density, and Markers of Immune Stress,” FASEB J 12 (1998) : A244.
  • Lowery, et al., “Conjugated Linoleic Acid Enhances Muscle Size and Strength Gains in Novice Bodybuilders,” Med Sci Sports Exerc 30 (1998) : S182.
  • MacDonald, H.B., “Conjugated Linoleic Acid and Disease Prevention: A Review of Current Knowledge,” J Am Coll Nutr 19.2S (2000) : 111S-8S.
  • Pariza, M.W., et al., “Mechanism of Body Fat Reduction by Conjugated Linoleic Acid,” FASEB J 11 (1997) : A139.
  • West, D., “Reduced Body Fat with Conjugated Linoleic Acid Feeding in the Mouse,” FASEB J 11 (1997) : A599.