- Anti-cancer effect
- CLA showed beneficial effects in human and animal experiments regarding cancer treatment at all stages (and in prevention too).
- Improving body composition
- Isomers of conjugated linoleic acid can promote fat-loss and a concurrent increase in lean body mass (even though it is questionable for humans).
- Regulating blood sugar levels
- It seems to raise insulin sensitivity, thus lowers blood sugar levels, and can be beneficial for type 2 diabetes.
CLA, the so called conjugated linoleic acid is a collective name for several isomers of linoleic acids. (Isomers are molecules of the same atomic composition, but with different 3D structures. This makes different isomers have different biological effects, or no effect at all.) So ‘CLA’ is not name of one particular material. CLA isomers always have conjugated atomic chains, as opposed to basic linoleic acid.
These isomers are fatty acids, which make them nutrients. The main sources are of animal based food: meat, egg, and (most of all) dairy products. Vegetable oils contain much less of it, but conjugated linoleic acids are still produced from sunflower oil (after special treatment).
CLA offer many possible benefits, but only a few have been confirmed. Such benefits are anti-cancer effects, lowering of blood sugar levels and preventing diabetes, lowering plasma lipid levels, and two-fold improvement of body composition (loss of body fat, increase in lean body mass).
The CLA mode of action is not verified at either case. The best documented benefit is probably the anti-cancer effect of the two most tested isomer (cis-9 trans-11 & trans-10, cis-12) – we’ll mean these two isomers when mentioning CLA from now on. We are not sure about how CLA prevents cancerous processes, but it seems that it reacts directly with carcinogenic materials thus curtails their carcinogenic potencial. Researches show that CLA mitigates tumor development at all stages, so it might be used for prevention, and possibly tumor reduction.
First CLA has been thought to fight cancer by being an antioxidant, but today it is clear that CLA shows no signs of antioxidant properties (as several tests confirmed this).
Positive effects of CLA on diabetes are more debated. Several tests verified that it increases insulin sensitivity, and lowers blood sugar levels. One study states the decrease in blood sugar is a result of CLA making muscles to store more glycogen – nad that would be a huge benefit for body builders. (Chromium picolinate and CLA enhances glycogen storage) This would make CLA similar to ALA, even though the effects of ALA is much better tested and verified. Animal tests showed all CLA-related benefits to be significant, but only a few human tests were carried out, and their results were less clear. Nonetheless researchers suspect that the decrease in sugar blood levels is linked to CLA activating several subtypes of PPARs (peroxisome proliferator activated receptors) that are nuclear receptors, and have an effect on carbohydrate and fat metabolism.
The same feature of CLA is thought (and is confirmed in animal tests) to lower the levels of triglycerides, and probably cholesterol in the blood.
So we can see that administering CLA can be justified to prevent or treat cancer, to treat type 2 diabetes, and probably to lower plasma lipid levels of people with heart condition – but what about athletes?
In 1994 several animal (e.g. rats) studies showed that CLA is capable of lowering body fat percent while increasing lean body mass. CLA was thought to be a new growth factor. Since then it mechanism behond body fat decreasing effects CLA has been found to be two-fold: it decreases the size and the number of adipose cells too. (Effects of CLA and guarana combined on body composition, plus the number and size of adipose cells) A test was carried out in 2004 with two alterations from the standard proceedings: they tested full-grown animals (after their developing stage), and regular exercises were introduced to the daily routine of the rats. The result was absolutely negative, none of the body composition benefits of CLA could be registered. But of course it is human testing that we are interested in the most. Here you can read the main points of two conclusive studies from 2003 that were carried out in order to clarify the effectiveness of CLA as of previous tests. Both studies underline the fact that animal tests showed CLA to be very effective for mice, rats, hamsters and pigs too. But one study concluded CLA effects to be insignificant for humans (if any) either at enhancing fat loss or promoting muscle development. The other study found 8 human experiments to be veritable (with large enough number of cases, having a control group, etc.), 4 of which showed positive effects of CLA, but also states that effectiveness was found to be just above the margin of error (making the results barely significant) – so even the studies with positive results detected minor changes. The same was stated by an overview in 2004 that found two studies only to be significant at verifying positive CLA effects, and it also underlined that these effects were meagre. However the same study pointed out that all studies handled feeding and body exercise ad libitum.
These would make the situation pretty obvious, but two well-prepared studies have been carried out since then. One followed overweight, but otherwise healthy people taking CLA for a year without training and diet, and both effects on body composition was found to be positively verifiable. The results were not that drastic, but probably there is no natural supplement that could induce sudden results. Another study ending in April 2005 followed CLA intake for two years, and found slight, but significant fat loss compared to the control group. Another aspect is that the length of the study proved CLA consumption to be safe. A newer (but not human) research from May 2005 studied CLA effects on overweight mice, and found convincing results.
The main problem with these studies is that they were carried out on groups of overweight and unfit people, and with no exercise or diet introduced. It seems that such people could experience some results (but not dramatic) from taking CLA. Bad news is that the only study we could dig up being really relevant to us (carried out with heavy athletes doing diet and exercises) showed no results at all. The study from 2002 could detect no increase in performance or muscle mass, nor loss of body fat while doing training and following a diet. The study is dated 2002, so we contacted leading researcher Richard Kreider whether since then he had found anything that made taking extra CLA recommended for body builders. Here you can read his reply word by word: “No. There may be some benefit for weight loss but it doesn't appear to influence muscle mass or strength.” This makes CLA a pretty contraversial substance that can improve body composition in certain cases (mainly by burning fat burning rather than developing muscles), but to a small extent only.
Why it is worth using?
- It is an anticarcinogenic substance that can be beneficial at any stages of cancer (including prevention).
- It might also support the improvement of body composition mainly by promoting fat loss. It also seemed to enhance lean mass growth in some cases.
- It seems to raise insulin sensitivity, thus lowers blood sugar levels, and can be beneficial for type 2 diabetes.
- Conjugated linoleic acid lowered triglycerid and cholesterol levels of the blood in some cases.
How to use it?
Most CLA products contain the mixture of the two isomers mentioned above. The average daily dose is 1–2 grams, but in most experiments (many of which still found it ineffective) at least 3 grams were administered daily.
Main natural sources include animal based food: meat, egg, and most of all milk and dairy products.
Warnings, side effects
CLA proved to be safe to take for long periods too. Daily doses exceeding 2 grams can lead to digestive problems (vomiting, diarrhoea) in very rare cases.
CLA is a relatively new supplement, therefore children, and pregnant or nursing women should avoid taking it.
Toxicity: Not known.
CLA is known to science from the 1930’s, but its beneficial effects were first observed in 1987 by researcher Pariza (after nine years spent isolating the substance).
Hi, I’m about to finish my steroid course, and I’d like to know whether you recommend CLA following the course to keep the muscles gained?
Hi, To be honest I’d save that money to buy extra BCAA on top of the amount you originally planned!
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A CLA csökkenti a testzsírszázalékot és vércukorszintet - http://www.tesztoszteron.hu/tudomanyos.php?id=18
A króm-pikolinát és a CLA fokozzák a glikogén raktározást - http://www.tesztoszteron.hu/tudomanyos.php?id=32
A CLA és guarana kombináció hatása a testösszetételre, a zsírsejtek méretére és számára - http://www.tesztoszteron.hu/tudomanyos.php?id=47
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