The Science of MCTs

 The Science of MCT’s

Although they are not exactly new, MCTs have gained a lot of recognition over the last few years in the world of dietary supplements. Some feature them as part of the keto dieting craze, others brought them to the forefront of their products due to the unique natural energy they provide. Regardless of the reason, they can be a useful tool in the arsenal of many for a variety of applications. Today the goal is to explain what MCTs are, the research proven benefits of what they can do and a quick discussion of some of the best forms available via supplementation.

What are MCTs?

First and foremost, Medium Chain Triglycerides, known commonly as simply MCTs are a type of saturated fat in which there are only 6-10 carbons in the fatty acid chain. Within this class, (known also as Medium Chain Fatty Acids or MFCAs), included are Caproic acid (C6), Caprylic acid (C8) and Capric acid (C10) and Lauric acid (C12.). Some will debate the inclusion of Lauric acid into this group as it has properties of both MFCA and long chain fatty acids, it technically does not fit the traditional definition, but we will cover it due to popularity. We will cover the differences between the most common ones (C8, C10 and C12) later in the article.

MCTs occur naturally in nature, however this is only in limited quantities in dairy fat and tropic oils. This leads to many defaulting to thinking that coconut oil is the same as MCTs, however it is important to note that coconut oil by nature only has a Capric acid content of 6.8% (palm kernel oil has 3.7% Capric). MCTs have a very low melting point which is why it is an oil at room temperature while other saturated fats are solids, another unique property of this fatty acid classification1.

In supplement form, MCT oil is typically a combination of caprylic acid (50-80%) and Capric acids (20-50%), usually extracted from coconut and palm kernel oil. They are then distilled and mixed into the desired ratio and combined with glycerin to form triglycerides though the use of solvents and lipases.

Now one key differentiating factor for MCTs aside from the length of the fatty acid chain is the metabolism of these fatty acids as one may imagine. They enter systemic circulation from the lymph at a relatively slow rate and deliver the fatty acids mostly to tissues such as muscle and adipose tissues rather than the liver. They are also unique in that they are not used much in the Krebs cycle, meaning that they are redirected toward ketone production (why they are popular with Keto diets) and little to none are used in fat synthesis/storage2.

It is also important that since Keto is a trending thing to note that MCT oils consisting primarily of Caprylic acid (C8) has a greater blood ketone response compared to other MCT mixtures (up to 25% greater), meaning that Caprylic acids are a powerful driving force of many ketogenic MCT oil products. This is a huge advantage of a specialized MCT powder such as C8Vantage? as it provides a pure source of this highly desirable MCT source3.

What Are the Benefits of MCTs?

While a large amount of attention for MCTs has been in the realm of what is promoted for those pushing the ketogenic diet and related products, there are actually quite a few benefits of these particular fatty acids that go well beyond being associated with a diet that is currently trending. Let us outline some of the key benefits that have been touted regarding MCTs.

Reduced Appetite & Overall Food Intake

When it comes to dieting, one of the biggest obstacles that many face is managing their hunger to stick to a calorie deficit and not giving into the hunger pangs associated with a diet. MCTs have shown promise in a few studies of being able to help increase satiety and reduce overall food intake when they are implemented.

A 2019 study involved 29 participants in four total trials which they consumed a breakfast consisting of either LCT or MCT in either solid or liquid form. Appetite ratings and gastric emptying (GE) were taken at baseline and at 15 min intervals for 4 hours following the ingestion of either MCT or LCT and energy intake was assessed at an ad libitum meal and via weighed food records for the remainder of the day. It was observed that food intake over the whole day was significantly lower in the MCT consuming group compared to the LCT group. It was also observed that the GE times with liquid MCT including breakfast group were significantly longer than that of the LCT groups, therefore it was concluded that MCT reduced subsequent calorie intake throughout the day without affecting subjective sensations of appetite when consumed in liquid form4.

Due to the large popularity of coconut oil and the aforementioned misconception that it is the same as MCTs, I want to also point out a 2017 study comparing coconut oil and MCT oil. This particular study compared the effect of MCT oil to that of coconut oil regarding satiety and overall food intake. Researchers had the participants consume a breakfast smoothing containing 250 kcals of either MCT oil, coconut oil or vegetable oil (control) on three separate test days. Appetite ratings were recorded, and participants were presented with an ad libitum lunch meal of preselected sandwiches 180min after consumption of the breakfast. Results showed significant differences in energy and macronutrient intakes between the three with MCT oil reducing food intake compared to the other two and that MCT also increased fullness over the three hours after breakfast compared to the control and coconut oils. Overall it was concluded from the results of this study that large differences exist between MCT and coconut oil and coconut oil cannot be promoted as having similar effects to MCT oil on food intake and satiety5.

Supporting Cognition

Another area that MCTs are touted for are the market improvements in cognitive function due to their production of ketones which can increase cognition. Through the implementation of them in supplementation whether in direct form or combined in things like hybrid coffee type beverages, MCTs have gained traction here and for good reason, however one thing that needs to be covered a little deeper is this application in normal populations and not those with specific disease states, so a lot of it is reported anecdotal evidence based on the ketone connection. With this noted, the studies that were done still do have very solid data and can prove useful for many including these populations.

Overall the data of two studies that are commonly referenced has suggested that MCTs (specifically Caprylic Acid) can enhanced cognitive function after both a single 40mL dose as well as daily intake of 20g over the course of 90 days in older adults that have been diagnosed with mild to moderate cognitive impairment6,7.

Better Energy Source – Less Fat Storage

A big benefit of MCTs is their ability to provide a readily available and rapidly utilized source of energy. Mind that they are utilized in a different pathway compared to traditional fats (LCTs), MCT are absorbed and digested rapidly and preferentially used in the body as a fuel source rather than stored (yes, they can still be stored as fat if consumed in excess) making them a more ideal fuel source.

MCT are rapidly oxidized in the liver and several human animal studies have shown that this rapid rate of oxidation leads to greater energy expenditure (EE) and ties in directly to the aforementioned fact that it has been demonstrated that the greater EE with MCFA relative to long-chain fatty acids (LCFA) results in less body weight gain and decreased size of fat depots after several months of consumption8.

Increased Calorie Burning/Greater Fat Loss

It has also been demonstrated that MCTs (primarily C8 and C10) can also increase the overall ability of the body to burn fat and increase overall calorie expenditure, a very useful tool that can be implemented for some. This of course must be implemented by REPLACING some of the current fat intake with MCTs, not simply adding MCT to the diet.

In a 1996 study, researchers examined whether MCTs in low to moderate amounts consumed along with meals can increase energy expenditure and 24-hour excretion of catecholamines in human subjects and conducted it in a group of 8 healthy young men. The subjects had their 24 hour EE and urinary catecholamine excretion measured in a respiratory chamber on 4 separate occasions with randomized combinations of MCT and LCT for a total 30g/day, which was consumed with their habitual diet in three equal parts (10g each) at breakfast, lunch, and dinner in the following ratio of MCT: LCT (g/g) 0:30, 5:25, 15:15 and 30:0. Results showed that the 24-hour EE significantly increased in the MCT:LCT ratio when the diet provided 15-30g of MCT/day, stimulating up to a 5% increase (a mean increase of 500 kcals/day)9. A solid study, but it is worth pointing out the relatively small sample size of only 8 participants, so a larger study would be beneficial to explore this more.

Another study, conducted in 2003 compared the effects of diets rich in MCT and LCT on body composition, energy expenditure, substrate oxidation, subjective appetite, and ad libitum energy intake in overweight men. 24 healthy but overweight men with BMI of 25-31 consumed diets rich in MCT or LCT for 28 days each in a crossover randomized controlled trial. At baseline and after 4 weeks of each dietary intervention, energy expenditure was measured using indirect calorimetry, and body composition was analyzed using magnetic resonance imaging. The results indicated that there was a decrease in upper body adipose tissue, a greater loss in whole body subcutaneous fat and an overall compared to traditional LCT intake10.

C8 vs. C10 vs. C12

Now that we have covered what MCTs are and the various benefits of them, let us wrap up with a brief coverage of the individual nuances of the differences between the various fatty acids in this class. The most common ones that are focused on are C8 (Caprylic acid), C10 (Capric acid) and C12 (Lauric acid), though as we mentioned the C12 is not technically a ‘true’ MCT by definition.

C8 – The Energy Catalyst

C8 MCT (Caprylic acid) is the predominant MCT found in things like coconut, palm oil, butter, and full fat milk of mammals. It is the shortest of the MCTs, making it the most rapidly assimilating and this is why it is regarded as a fantastic source of rapid energy also in part because it is rapidly turned into the substrate known as ketones which have been suggested to be even more efficient than glucose. It also has specifically been shown to potentially have the satiating effect via studies that have indicated it may acylate ghrelin (aka the ‘huger hormone’), the only known peptide hormone with an orexigenic effect. It has also been shown to be beneficial as an antibacterial and aid in reducing gut inflammation via suppression of interleukin 8, translating to smoother digestion and helping those with leaky or gut sensitivity.

One specific version of this that I have been using in formulation for a variety of reasons is the C8Vantage? from NNB Nutrition. This particular version has some added benefits I like such utilizing pea protein and tapioca for prebiotic fiber as carriers for powder format. It is also desirable as it provides a pure source of the desirable C8 fatty acids for the specific energy production/ketone producing properties having had the C10 and C12 fatty acids removed and as a result also can produce the highest amount of ketones possible, eliminating the insulin response making it ideal for a variety of applications. Another good use for it being qualified as vegan is that it makes a nice addition for plant protein formulations and I like it as a flavoring component for enhancing mouth feel.

C10 – Antifungal & Immune Boosting

C10 also known as Capric acid is another true MCT fatty acid that is also found in coconut and palm kernel oil. It has specific benefits more so on the side of antifungal properties such as data suggesting that in the gut it can mitigate 3 strains of Candida albicans, a yeast that can cause digestive issues11.

There has also been data suggesting that C10 can be beneficial in a breast-feeding application. In one particular study, C10 was supplemented to breastfeeding mothers and the antimicrobial properties were passed onto the infants, resulting in increased resistance to infections and viruses. Though this is a very cool characteristic, this same power hasn’t been noted in a study as of yet in adults12.

C12 – Antimicrobial, & Skin Improvement

While C12 (Lauric acid) is considered to not be a ‘true’ MCT, it still possesses enough properties and popularity to be discussed, especially with the benefits associated with it. It makes up a large percentage of the fatty acids in coconut oil but can also be found in palm oil. It is notoriously the most potent antimicrobial of the MCTs as it is converted into a substance called monolaurin, a compound that has been shown to kill pathogens like Staph, E. coli, herpes simplex and even measles13.

Another cool and specific benefit of C12 is that it appears that due to it’s antimicrobial properties, C12 can be an effective acne treatment, maybe even more so than over the counter acne medications that use the drug benzoyl peroxide in some subjects14.

Conclusion

Through the scope of this article, I hope that I was able to shed a brief but informative insight into what medium chain triglycerides are and why they are of great benefit for a variety of uses and users. While you (like myself) not be a keto enthusiast, don’t let the hype and correlation to this trending diet fool you: MCTs aren’t a new thing and their benefits are indeed real and here to stay. Consider giving them a shot and seeing how they impact you personally and you may just be surprised the effects they have on overall health, digestion, and energy levels.

REFERENCES

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2.          Dias V. Effects of Medium-Chain Triglyceride Feeding on Energy Balance in Adult Humans. Metabolism. 1990;39(9):887-889. doi:10.1016/0026-0495(90)90295-n

3.          Vandenberghe C. Tricaprylin Alone Increases Plasma Ketone Response More Than Coconut Oil or Other Medium-Chain Triglycerides: An Acute Crossover Study in Healthy Adults. Current Developments in Nutrition. 1(4). doi:10.3945/cdn.116.000257

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6.          Reger M. Effects of Beta-Hydroxybutyrate on Cognition in Memory-Impaired Adults. Neurobiol Aging. 2004;25(3):311-314. doi:10.1016/S0197-4580(03)00087-3

7.          Henderson S. Study of the Ketogenic Agent AC-1202 in Mild to Moderate Alzheimer’s Disease: A Randomized, Double-Blind, Placebo-Controlled, Multicenter Trial. Nur Metab. 2009;6(31). doi:10.1186/1743-7075-6-31

8.          St. Onge M-P. Physiological Effects of Medium-Chain Triglycerides: Potential Agents in the Prevention of Obesity. J Nutr. 2002;132(3):329-332. doi:10.1093/jn/132.3.329

9.          Dulloo G. Twenty-four-hour Energy Expenditure and Urinary Catecholamines of Humans Consuming Low-To-Moderate Amounts of Medium-Chain Triglycerides: A Dose-Response Study in a Human Respiratory Chamber. Eur J Clin Nutr. 1996;50(3):152-158.

10.        St. Onge M-P. Medium-chain Triglycerides Increase Energy Expenditure and Decrease Adiposity in Overweight Men. Obes Res. 2003;11(3):395-402. doi:10.1038/oby.2003.53

11.        Bergsson G. In Vitro Killing of Candida albicans by Fatty Acids and Monoglycerides. Antimicrob Agents Chemother. 2001;45(11):3209-3212. doi:10.1128/AAC.45.11.3209-3212.2001

12.        Francois C. Acute Effects of Dietary Fatty Acids on the Fatty Acids of Human Milk. Am J Clin Nutr. 1998;67(2):301-308. doi:10.1093/ajcn/67.2.301

13.        Kabara J. Fatty Acids and Derivatives as Antimicrobial Agents. Antimicrob Agents Chemother. 1972;2(1):23-28. doi:10.1128/aac.2.1.23

14.        Nakatsuii T. Antimicrobial Property of Lauric Acid Against Propionibacterium acnes: Its Therapeutic Potential for Inflammatory Acne Vulgaris. J Invest Dermatol. 2009;129(10):2480-2488. doi:10.1038/jid.2009.93