MCT oil is a popular supplement for its possible benefits on weight, body composition and sports performance. MCTs are unique, saturated fats.
I went to my first CrossFit class last week (which by the way was SO fun!) and I saw a bag of MCT oil powder sitting out. I realized we haven’t talked about using MCT oil on this blog yet, so it’s time to dive in. We’ll cover what is MCT oil, what are the benefits (or potential benefits) and bottom line: should you take MCT oil?
Let’s first start off with breaking down what MCTs, AKA medium-chain triglycerides, are.
What are MCTs?
Fats differ by their chain length (number of carbon atoms) and degree of saturation. Mono- and polyunsaturated fats have one or more double bonds, respectively, while saturated fatty acids have no double bonds. Medium chain triglycerides, or MCTs, are saturated fats with a chain length between 8 and 12 carbons (1,2,3). Most fats in the American diet are 12 or more carbons in length (3).
There are three types of MCTs that differ based upon their chain length:
- Caprylic acid (C8:0) – that means 8 carbons and no double bounds
- Capric acid (C10:0)
- Lauric acid (C12:0)
The majority of research on benefits of MCTs are attributed to C8:0 and C10:0 MCTs.
Possible Benefits of MCTs
MCTs are unique in their metabolic pathway, how quickly they are digested, and their effect on fat storage.
Absorption and Metabolism of MCTs
MCTs are absorbed differently than your typical fatty acids. MCTs bypass the lymphatic system and are transported directly into the portal vein to the liver where they are oxidized quickly through the beta-oxidation pathway (3,4). MCTs are more likely to be used as energy, less likely to be stored as fat in the body and may increase thermogenesis (basically cause your body to use more calories to break down the food you eat).
Other Possible Benefits & Findings of MCTs
Inconsistent research has shown weight loss, improved body composition and enhanced sports performance with MCT use (3,4,5,6). MCTs can make the body produce more ketones, which allows people on a ketogenic diet to eat more carbs than they would otherwise be able to while staying in ketosis. Inconsistently, some research has shown increased satiety (fullness) resulting in decreased caloric intake with MCTs (4). MCT does not appear to affect triglycerides, total cholesterol, low-density lipoprotein (LDL) or high-density lipoprotein (HDL) levels (4,7). Notably, dosages used in the trials and meta-analyses reviewed varied widely.
Clinical Uses of MCTs
Clinically, we use MCT supplements in chyle leaks and some cases of fat malabsorption (although usually if it’s due to pancreatic insufficiency we use pancreatic enzymes) or other errors of fat metabolism.
Where are MCTs found naturally-occurring in food?
There are a few foods that contain some amount of MCTs; none are pure MCT. In descending order, they are: coconut oil, palm kernel oil and dairy (1). The amount and type of MCT varies between each of these sources. The effects of pure MCT should not be extrapolated to food sources containing some amount of MCT only. (Notably, 60% of the saturated fat in coconut oil is C12:0 and C14:0 which has not shown the same beneficial effects as C8:0 and C10:0).
Interestingly, MCT is an important component in breastmilk.
Where do MCT supplements come from?
Most MCT supplements are in the form of MCT oil, which is a by-product of producing margarine (1). Some MCT supplements also come from coconut oil, however remember that many of those triglycerides are in the form of C12:0, rather than C8:0 and C10:0.
Are there down sides to MCT supplements?
Gastric discomfort is noted as a common side effect.
Bottom Line, Should You Take MCT Supplements?
In my opinion, it’s probably not necessary to take MCT supplements. I’m not opposed to using whole MCT oil in cooking (best in salad dressings, spreads and can be swapped in many recipes). The strongest case for MCT oil seems to be for weight loss. That said, the average finding was -0.51 kg (1.1 lb) over 10 weeks which is statistically significant but may not be clinically significant (meaning going to make a major change in your health risk). The findings on body composition changes are promising but somewhat inconsistent. Changes in sports performance are likewise inconsistent. We aren’t seeing negative changes in lipid profiles which makes it safe to try. I’d be interested to see more research on: its use replacing long chain triglycerides in the diet in regards to weight, performance and body composition and standardized dosage for beneficial results.
As usual, there were more studies reviewed than notated here. To maintain as much brevity as your attention span will allow, I whittle down findings. I hope this is helpful for you!
Have you tried MCT oil supplements?
What has your experience been with MCT oil supplements?