Elongation and Desaturation: You can’t fool the body!
“Too much of what has been written or said in textbooks or journals about fats and oils is either incorrect or unacceptably incomplete.” Dr. Mary Enig, author, Know Your Fats
Palm oil is obtained from the fleshy mesocarp of the oil palm fruit. Palm oil is 45 percent sautrated palmitic acid.
Saturated palmitic acid (16:0) is called the “stem” fatty acid because it is the basic fatty acid the body makes de novo – a stem fatty acid to make other fats. Palmitic acid protects our lungs, making up 68 percent of lung surfactant. Palm oil is highest in palmitic acid (45%) – hence the name. Butter, chicken fat, cocoa butter, lard, beef and lamb fat all contain 25-26 percent palmitic acid. Human milk fat is 20-25 percent palmitic, while olive oil is 14 percent palmitic acid.
Found abundantly throughout the living world, why would the experts in health and nutrition call palmitic acid ‘bad’?
No naturally occurring fat or oil we consume is made exclusively of either saturated or unsaturated fat. Even dominantly polyunsaturated flax oil is 9 percent saturated – containing both palmitic (16:0) and stearic acid (18:0). A totally saturated fat would be indigestible – as hard as wax – and totally unsaturated oils do not exist in our food supply.
A brief description of Elongation and Desaturation
Palmitic acid (16:0) is the most common saturated fat in our food and in the living world. Humans (and other animals) also make or synthesize palmitic acid from acetyl-Co A – an elementary breakdown product of carbohydrate, protein and fat metabolism. As the stem fatty acid, saturated palmitic acid can be converted into monounsaturated fat.
In Dr. Mary Enig’s words, fatty acid conversions are made by the body “to maintain desirable physiological balances.” Saturated fats can be converted into monounsaturates and, as needed, monounsaturates like oleic acid (18:1) can be converted back into saturated fats.
As an example, via the process of elongation, the liver and other tissues can add two additional carbons turning 16 carbon palmitic into 18 carbon stearic, which, in turn, converts into monounsaturated oleic acid through a special process called desaturation – inserting a double bond into the chain where previously there was none.
You can’t fool the body. Eat a lot olive oil – and in order to maintain optimum cell membrane stiffness – the monounsaturated oleic acid will be converted into saturated fat. Afraid of eating too much saturated fat? Don’t be! Your body will convert any excess saturated into monounsaturated oleic acid.
Take-away lesson: Eat a variety of natural fats from whole foods and unrefined oils – your body will take care of the rest. For cooking, stick to the traditional more saturated and monounsaturated fats, including beef and lamb tallow (drippings), butter, coconut oil, lard (pork fat), palm oil, extra virgin olive oil, and high quality sesame oil for stir-fry.
Category: Fats/Oils
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