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Conjugated Linoleic Acid

Review of Conjugated Linoleic Acid (CLA)

What is CLA?

Conjugated Linoleic Acid (CLA) is a type of fatty acid that is found naturally in our diet.  It is present in relatively high levels in unprocessed sun flower oil and is also found in milk and other dairy products.  CLA has many positive effects including a reduction in body fat, preservation of muscle mass, reduced rates of artherosclerosis (furring of arteries), more stable blood sugar levels.

Who Should Consider Taking CLA supplements?

Anyone looking to decrease body fat levels, increase muscle size, and increase the rate of recovery may benefit from CLA.  Therefore CLA will be beneficial for weight loss, strength athletes, or anyone involved in strenuous exercise.

Summary of CLA's Phyiological Effects:

  • Reduces fat storage
  • Increases the rate of fat metabolism
  • Preserves and increases lean muscle mass
  • Increases muscular strength
  • Decreases the levels of the "bad" LDL cholesterol
  • Decreases appetite
  • Lowers cortisol levels

CLA Research

CLA appears to aid fat loss by three main mechanisms: 1) CLA reduces that amount of dietary fat that is stored as fat in our bodies.  It does this by inhibiting key enzymes that would otherwise cause dietary fat to be stored in our fat cells; 2) CLA increases the rate at which fat is metabolised, and; 3) CLA leads to increases in lean muscle mass which in turn speeds up the metabolism and therefore an increased metabolism of fat.

Research has demonstrated that when CLA is taken at a dose of 3-6g per day, it increase the rate of fat loss as well as increasing lean mass (Blankson et al., 2000).  The consumption of 3.4g of CLA, per day, led to reductions in body fat mass, decreased levels of the bad LDL cholesterol, and maintained levels of the good HDL cholesterol (Gaullier et al., 2005).  Therefore, not only does CLA help to reduce body fat but it may also help to reduce the risk of artherosclerosis (furring of arteries).  The researchers concluded that the consumption of CLA decreases body fat mass in overweight humans, and may help to maintain initial reductions in body fat mass and weight in the long term.  They also found that the consumption of CLA for 24 months caused no serious adverse effects.

Another, positive of CLA supplementation is that it appears to increase feelings of fullness, whilst decreasing feelings of hunger (Kamphius et al., 2003).  Therefore, it may also aid weight loss by having an appetite suppressing effect.

As well as increasing fat loss and lean body mass, CLA has also been shown to lead to significant increases in strength (Lowery et al., 1998).  The gains in lean muscle mass and strength are likely to be due to CLA’s ability to lower the level of cortisol in the blood.  Since cortisol has a negative effect on muscle mass, by increasing the breakdown of muscle tissue, lowering cortisol levels will lead to reduced muscle breakdown and will increase the rate of recovery after exercise.

Is CLA effective?

CLA has been demonstrated to enhance fat loss whilst maintaining or increasing lean muscle mass.  It has been shown to enhance muscle gains, strength gains, whilst lowering cortisol levels.

How to take CLA?

In order to reduce body fat levels and increase lean muscle mass you should aim to consume 3-6g of CLA per day.  This should be split into three doses of 1-2g taken with food.

CLA References

Blankson, H., Stakkestad, J. A., Fagertun, H., Thom, E., Wadstein, J. and Gudmundsen, O. (2000). Conjugated linoleic acid reduces body fat mass in overweight and obese humans. Journal of Nutrition. 130, 2943-2948.  

Gaullier, J. M., Halse, J., Hoye, K., Kristiansen, K., Fagertun, H., Vik, H. and Gudmunsen, O. (2005) Supplementation with conjugated linoleic acid for 24 months is well tolerated by and reduces body fat mass in healthy, overweight humans. J Nutr. 135 (4), 778-784. 

Kamphuis, M. M., Lejune, M. P., Saris, W. H. and Westerterp-Plantenga, M. S. (2003) Effect of conjugated linoleic acid supplementation after weight loss on appetite and food intake in overweight subjects. Eur J Clin Nutr. 57 (10), 1268-1274. 

Lowery, L. M., Apicelli, P. A. and Lemon, P. W. R. (1998) Conjugated linoleic acid enhances muscle muscle size and strength gains in novice bodybuilders. Medicine and Science in Sports and Exercise. 30, S182.