A couple of definitions:
Fatty acid – A carboxylic acid made up of varying numbers of carbons. Can be short (less than 6 carbons), medium (8-12 carbons), long (14-20 carbons) or very long (greater than 22 carbons) depending on the number of carbons. Most dietary sources of fat contain more long chain fatty acids.
Triglyceride – A fat molecule made up of a glycerol backbone and 3 fatty acids.
MCT (Medium Chain Triglyceride) - 2-3 of the 3 fatty acids must be medium chain in length. These fats are typically saturated fats.
MCT Oil - a product made up of only medium chain triglycerides. Typically derived from coconut oil or palm kernel oil. Also called Liquid Coconut oil or Fractionated Coconut oil.
I know that MCT oil has become popular over the last few years, but I have some concerns over its use in the diet of healthy individuals, especially those who are trying to get back to a pre-industrial and/or pre-agrarian way of eating.
MCT oil is derived from either coconut oil or palm kernel oil. On the surface it might seem like a good idea because it is derived from “natural’ sources, however in order to get it into a pure liquid state containing only MCTs, coconut or palm kernel oil has to be highly industrially processed. This exposes it to high heat and pressure, along with several catalysts.* MCT oil does not exist in nature. It is a man made product. For anyone interested in getting back to eating in a less processed, pre-industrial way, MCT oil in no way fits with that goal. For me, this is enough of a reason to avoid it.
But you probably heard that coconut oil has positive nutritional and health benefits, mainly owning to its large proportion of medium chain fatty acids, which make up the MCTs, so wouldn’t an oil that contains just those beneficial fatty acids be even better?
Except, there is not just one medium chain fatty acid in coconut oil, there are actually three: Caprylic acid, which has 8 carbons (C8:0), Capric acid, which has 10 carbons (C10:0) and Lauric acid, which has 12 carbons (C12:0.)
Caprylic acid and Capric acid make up roughly 15-20% of the fat content of coconut oil. Lauric acid accounts for 50%.
Caprylic acid and Capric acid can be found in similar amounts in other sources (namely goat’s milk, for which they are named - the Latin word for goat is caper.)
The single best source for Lauric acid is coconut oil. The second best source for Lauric acid is human breast milk, which only has 6% Lauric acid. Most of the positive health benefits of coconut oil (antimicrobial and antifungal properties; its positive impact on HDL levels) seem to be traced back to its large concentration of Lauric acid.
There is also evidence to suggest that Lauric acid may be what is called a “conditionally essential” fatty acid. This means that under certain conditions the body cannot make Lauric acid on its own and must get it from the diet.
And here’s where the MCT oil gets sneaky. It would logically make sense that MCT oil derived from coconut oil would have all three medium chain fatty acids, but it doesn’t. MCT oil only contains Caprylic acid and Capric acid. I wont bore you with the reasons for this (which are functional, not nutritional), because the bottom line is that MCT oil only contains Caprylic and Capric acids.**
Being man made and containing only two fatty acids means that MCT oil is a product that does not exist in nature. There is no real, whole food that contains only Caprylic and Capric acids. There is no real, whole food that contains the percentage of Caprylic and Capric acids found in MCT oil.
Of course, as with all nutritional conversations, the story is more complex, but at the end of the day these reasons are more than enough to convince me that I should reach for the coconut oil instead of the MCT oil or the liquid coconut oil.
*N.B. This processing can still technically be labeled "physical" but that does not mean that it could be done in your kitchen. It is still a lab-based manufacturing process.
**N.B. I have recently become aware of a liquid coconut oil product that claims to have all three medium chain fatty acids (Lauric, Caprylic and Capric.) I am highly suspicious of any product that makes this claim. The reason Lauric acid is not included in MCT oil is that it has an extremely high melting point (nearly 110° F) and therefore would not be liquid at room temperature. If there is in fact any Lauric acid in a liquid oil it would by necessity be in such small amount so as to be almost negligible.