It was about a year ago that a friend told me that coconut oil was not only good for you, but that it was poised to be the next big thing in the world of health foods. I remember reacting with surprise and incredulity - coconut oil? Isn’t that like, the most saturated of fats?
Yes, indeed, coconut oil is comprised of a lot of saturated fat (it is more than 90% saturated), which is why it has gotten a bad rap in the past. However, earlier this month the mainstream media outlet known as the NYT fulfilled my friend’s prophecy by publishing a story titled, “Once a Villain, Coconut Oil Charms the Health Food World.” So, what gives?
Well, one can categorize fatty acids on the basis of their saturation level (saturated, mono-unsaturated, poly-unsaturated), but fatty acids can also be categorized on the basis of their length. It is this latter issue that appears to be relevant to the purported health benefits of coconut oil. You see, although coconut oil is comprised of almost all saturated fatty acids, coconut oil is also predominantly comprised of medium chain triglycerides (a triglyceride contains three fatty acids). Medium chain triglycerides differ from long chain triglycerides (found in olive oil) in that they are more readily absorbed from the small intestine, they are rapidly metabolized in the liver for energy and not fat storage, and they do not contribute to the synthesis of cholesterol. This differs from long chain triglycerides, which require enzymes and vehicles (lipases and chylomicrons) for absorption and transport, and can be repackaged as triglycerides for fat stoage or cholesterol synthesis in the liver.
Ok, ok, you might say - so that is some interesting biochemistry (or you might not say that), but I have been raised to believe that saturated fat = bad and olive oil = good, so are you really suggesting that my body is going to burn coconut oil more efficiently than olive oil?
Yes. But, I’m not just suggesting it, folks have actually done the study (science is cool).
In a paper published in the International Journal of Obesity in 2003, investigators gave two groups of men diets that were matched on fat, carb, and protein ratios (40:55:15). However, 67% of the fats that the medium chain triglyceride group received had chain lengths of 8-10 (compared to 0% in the long chain group), whereas 84% of the of the fats in the long chain triglyceride group had chain lengths of 18 (compared to 24% in the long chain group). Over the next month (28 days), the medium chain group exhibited greater energy expenditure and lost significantly more weight (specifically, fat tissue) as compared to the long chain group, even though the saturated fat makeup of the medium chain group was 76% saturated fat, 14% mono-unsaturated, and 10% poly-unsaturated and the long chain group was 17% saturated fat, 71% mono-unsaturated, and 10% poly-unsaturated.
These data provide some convincing evidence in humans that the biochemical differences between medium and long chain triglycerides appear to translate into physiologically meaningful differences in metabolism and energy regulation.
So, is coconut oil a friend or foe? Let’s just say that it is a welcome guest in our house.