Udo Erasmus, pioneer of essential fatty acids, EFA's, omega-3, omega fats, Udo's Choice, Udo's Oil, cold-pressed flax-seed oil, trans-fats, Trans Fatty acids
Click for main Writings index
Click for Udo's Article Index
 
 
CLA - Conjugated or Compromised?

 

PART 2: What is CLA?



Conjugated linoleic acid (CLA) is a mixture of 8 (and perhaps even more) different forms (or isomers)2 of an 18-carbon fatty acid made by a high-heat industrial process from linoleic acid (LA), the omega-6 (omega-6) essential fatty acid (EFA). In nature, this is accomplished by bacteria in the stomach of ungulates: beef, goats, sheep and other cud-chewing animals (which include deer, moose, caribou, elk, buffalo, yak, musk ox), and CLA is found in meat and milk fat of these species.

Each of its eight different isomers has a different spatial structure and each therefore has different action in the body, with different effects on health. The isomer found in dairy products is mainly the (delta)9c,11t-18:2 isomer.3  Butter normally contains about 5mg of CLA per gram of fat, but this can be increased to 40mg per gram by feeding cows sunflower oil.4  Milk chocolate contained 0.3mg of CLA per gram chocolate in a study.5 Commercially, CLA is made by a high-temperature (overheating) process, or by hydrogenation of soybean6 or canola oils, or by transformation carried out by bacteria in one of the four stomachs of cud-chewing animals from the omega-6 EFA, LA.



How is LA Changed to CLA?

CLA is made from LA, the omega-6 EFA, by flipping one of the double bonds in the LA molecule one carbon closer to the other one. This changes the 'methylene-interrupted' double bonds present in EFAs (double bonds start 3 carbons apart) into 'conjugated' double bonds (double bonds start 2 carbons apart). At the same time, one of the double bonds found in the cis- configuration in an EFA (hydrogen atoms on the carbons involved in the double bond are on the same side of the molecule) twists 180�. The hydrogen atoms are now in a more stable, but biologically less desirable trans- configuration (hydrogen atoms on the carbons involved in the double bond are on opposite sides of the molecule). Trans- means 'across'. Hence the name trans- fatty acid.

Is CLA an Essential Nutrient?

CLA is not an essential nutrient. It is, like monounsaturated (n-9) and saturated fatty acids, a non-essential fatty acid. It is not required for human health. This means that, unlike the omega-6 and omega-3 EFAs, which we cannot live without, we can live on a CLA-free diet a whole life time and continue to be healthy. CLA is also a trans- fatty acid.



To be fair, the 9c,11t-18:2 (the letter "t" after the number "11" in this designation means: "trans") isomer of CLA found in milk fat and beef appears to be one of the more easily digested trans- fatty acids, and is therefore less toxic than the types of trans- fatty acids found in margarine, shortening, and partially hydrogenated vegetable oils. However, CLA interferes with the conversion of EFAs (especially omega-6) to derivatives from which the body makes the eicosanoid (prostaglandin) hormones.8 This should concern low fat dieters, who already get too little omega-6 EFA, LA. It should also concern those who use flax oil exclusively, because they get too much omega-3 in comparison to their intake of omega-6, and CLA will make their low omega-6 status even worse.

Conjugated Double Bonds

Conjugated double bond systems have antioxidant activity, and some studies suggest that CLA can perform antioxidant functions. Other studies suggest that CLA increases oxidation, which is not so good. However, there are hundreds of molecules with antioxidant activity equal to or better than that of CLA. Among those that, like CLA, are oil-soluble there are vitamin A, carotene, vitamin E, and many complex molecules with aromatic carbon rings.




Molecules with antioxidant activity provide protection against degeneration, and hence might have anti-cancer, anti-inflammatory, anti-diabetic, and cardio-protective properties. However, hundreds of molecules from nature provide equal or better protection against degeneration.
For instance, about half of all edible green plants contain anti-cancer, cardio-protective, anti-diabetic, anti-inflammatory ingredients-hundreds of different ones-and they confer their protection in many different ways.



Some people in the marketplace suggest that CLA is protective against degenerative conditions, but here too, the research is contradictory, and CLA may be over-rated. In the following pages, I summarized 43 clinical studies done with CLA. The remaining studies came to similar conclusions, or were of a technical nature. I have tried to report fairly. Check out the studies, and judge for yourself.

<<< Previous Page

 

 
Click to send us an email!