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Conjugated Linoleic Acid (CLA) is a natural fatty acid that is present in foods such as meat and dairy produce. Most commercial supplements are derived from Safflowers which are a naturally rich source of linoleic acid, a precursor to CLA. The two most common, biologically active isomers of CLA are the cis-9, trans-11 and trans-10, cis-12 isomers. Clarinol CLA contains a 1:1 ratio of these two isomers. Originally CLA was (unexpectedly) discovered as an anti-carcinogenic fat in fried meat, later its full range of biological effects were unveiled.
Soon after its discovery it was found that CLA induces fat-loss in mice. Due to increasing concerns over health problems resulting from people becoming overweight or obese, there has been over 65 clinical trials performed on humans investigating CLA as a supplement for fat loss.
Although, in isolation, not all of these studies show CLA mediated fat-loss, meta-analysis of large groups of these studies consistently show that CLA induces fat-loss in humans.
A separate meta-analysis focusing on the 14 studies on CLA which meet EFSA's strict quality criteria, demonstrated that CLA consistently reduced body fat by 6% in time periods ranging from 3 to 6 months.
In order to investigate the mechanism behind the fat-loss properties of CLA, a list of genes was composed which are affected by exposure to CLA (figure 1). All of these genes in isolation were proven to play a role in fat-loss.
|Lean body mass↑||+||+||+||++||+||+|
Figure 1. Genes affected as a consequence of CLA exposure play a role in fat-loss, increases in lean body mass and improved endurance. ++ means genetic and pharmacological evidence. + means genetic or pharmacological evidence.? means unknown, (+) means data for CLA only.
Interestingly, the same set of genes which play a role in fat-loss also play a crucial role in increasing lean body mass and improving endurance capacity.
All of these genes appear to work together in one biochemical pathway, affecting all of these parameters. This biochemical pathway shows large similarities to the biochemical pathway which is activated inside the body by exercise itself. Supplements known to activate this pathway are therefore called "exercise mimetics".
Although the physiology of laboratory animals and humans is similar, it should be stressed that most of the mechanistic evidence as described above was collected in laboratory animals. CLA also improves bone formation, improves strength, is anti-carcinogenic and anti-inflammatory.
These are all properties which are shared between CLA and doing exercise. This supports the interpretation that CLA may work as an exercise mimetic.
However, studies carried out using human subjects are scarce. CLA does induce fat-loss in humans, but this effect has only been demonstrated in overweight people. CLA has also be shown to increase lean body mass in humans, but due to the difficulties in quantifying this effect, this was only measured in a limited number of studies.
Optimal performance needs a good mindset, a trained (tuned) body and the availability of the right fuel to be burned metabolically for energy. In this process CLA cannot replace physical training. However, together with a balanced diet comprising of essential macro and micro nutrients, CLA may help to tune the body to perform optimally.
Nothing beats a healthy, balanced diet to provide all the nutrients we need. But when this isn’t possible supplements can help. This article isn’t intended to replace
medical advice. Please consult your healthcare professional before trying supplements or herbal medicines.