Let’s talk about a very important fat source, MCTs or Medium Chain Triglycerides, their benefits and uses..
What are MCTs
MCT (Medium Chain Triglycerides or Mid Chain Triglycerides) are a type of lipids in the form of fatty acid esters that present differences compared to other lipid structures that we normally find in foods.
Mainly the fats we consume through diet, as well as our deposits in the body, are found in the form of triglycerides.
Figure I. Chemical structure of a triglyceride.
A triglyceride is nothing more than a complex formed by alcohol + 3 fatty acids [tri (three) – acid (fatty acids) – glyceride (glycerol, alcohol)] in a chemically correct manner they are called triacylglycerols, which is the same as how you will find it written in my articles.
Figure II. Chemical structure of a fatty acid of different lengths.
Hydrocarbon chain fatty acids of less than 12 monomeric units are considered “medium chain fatty acids”, when three of them bind to a glycerol molecule we have an MCT.
The short chain fatty acids are an exception, as they are mostly produced in the colon from the fermentation of indigestible fibres in the small intestine, and are currently proposed as agents with potential to improve the microbial diversity of the intestine (Chambers et al., 2018).
But its presence in food is incredibly limited and in no case constitutes a relevant fraction of our caloric intake.
Nor are medium-chain triglycerides, as most of our fat intake comes from more than 12 carbons (palmitic, stearic, oleic, and fatty acids of the omega 3 and 6 series).
Wait, wait, I’ll get ahead of myself! I’m going to tell you why.
Differences between LCT and MCT
The big difference between triglycerides composed of long-chain fatty acids (LCT) and medium chain fatty acids (MCT) lies in their absorption and metabolization.
Figure III. Fatty acid (A), Glycerol (B) and fatty acid esters according to their units.
The fats we consume from our diet, as they are esterified, require a hydrolysis process for absorption.
This process begins in the mouth, with salivary lipase, which is responsible for breaking down these molecules; a process which continues in the stomach with gastric lipase.
Well in our gastrointestinal system the same thing occurs, the fatty acids and water do not get along… therefore they are “encapsulated” in structures formed from their emulsion by bile.
Figure IV. Digestion and absorption of LCT.
Since bile is composed of polar molecules, which “collide the 5 with water” without problems, form a “barrier” keeping the fatty acids inside so that they do not come in contact with the aqueous environment of the gastrointestinal system.
In the intestine, when they approach the enterocyte barrier (the cells of the intestine), a very acidic medium is present.
Here pancreatic lipase begins to cause fatty acids retained inside the micelles that protected them to exit so that they can be absorbed.
There, these fatty acids are re-esterified, forming triglycerides again (like at the beginning), which pass into the system through the lymph in the form of chylomicrons (again, protected to avoid contact with water).
Figure V. Absorption of the lipids in the enterocyte.
Did you see what happened? Well, forget it!
What happens with the MCTs?
Medium-chain triglycerides don’t need that much help..
Since their shorter structure allows them to be (relatively) soluble in water, and therefore do not require “protection” like LCTs, so they do not form micelles, nor re-esterify themselves in the cells of the intestine.
They are VIP guests in our body!
Figure VI. Digestion and absorption of lipids depending on their length.
MCTs as a source of energy
This is why researchers said:
“…hey, its absorption is as fast as glucose (Iber, 1974), will it be a good source of energy?…”
Fats are very energy giving, they provide 9kcal/g; medium chain fats provide a little less, 8.4kcal/g, but of course… they are much more efficient!
Figure VII. Metabolization of fatty acids with different chain lengths compared to glucose in hepatocytes.
In the liver long-chain fatty acids (after release by chylomicrons) they have to undergo a long process of acylation and pass to the mitochondria through the carnitine shuttle system, which “gives them the seal of approval for entry” and moves them into the mitochondria.
There, and then, they can break away from the carnitine, which comes back again, to continue helping long-chain fatty acids that are lost without it.
Figure VIII. Mitochondrial transport mechanism of an LCFA.
Medium chain fatty acids (remember that they reached the liver cells in a direct limo through the portal circulation system) enter the mitochondria like they own the place. There, they activate and can oxidize.
Therefore, MCTs are similar to glucose: their digestion, absorption and metabolization is simply no longer possible, and that’s why MCTs are an ideal source of energy in the form of fat, while LCTs… Meh, they’re worse.
Because MCTs reach the liver so fast, they saturate the tricarboxylic acid cycle (where energy is obtained from) and transform into ketones (mainly beta hydroxybutyrate).
Figure IX. Ketogenesis by saturation of the Krebs cycle.
And it goes wherever it wants, since, while fatty acids in hepatocytes go well, their use by extrahepatic tissues (such as muscle) is much less.
Having ketones in your blood is a good sign to be able to get energy, since these are easily used in muscle cells.
For example: producing ATP that we will use to continue giving everything in our training.
What if we are doing a keto diet?
There, glucose availability is already reduced, and its contribution through diet is minimal.
Here, this is where the MCT is key.
Because they act (thanks to their rapid absorption and conversion to ketone bodies) like the glucose we lack, but without stimulating insulin secretion or altering blood glucose, and without significantly affecting mTOR activation, thus not altering the ULK1 activation by AMPK, and therefore, not conditioning autophagy.
Figure X. Regulation of ULK1 according to the phosphorylated domain leading to the activation or inactivation of mTORC1/AMPK.
Practical applications of MCTs
Control of bodyweight
MCTs have mechanisms through which they have been postulated as possible substitutes (partial) to LCTs in weight loss diets.
The reasons behind this statement are diverse, we do not know exactly the exact mechanism through which they have this potential, and the results are heterogeneous.
It is suggested that they can cause an:
- Increase in satiety after consumption.
- Increase in fatty acid oxidation versus LCT consumption.
- Regulations on the rise of PGC-1α expression, mitochondrial biogenesis, and increased energy expenditure.
Although we are still not clear how MCTs can help control body weight, the fact is that the results of the trials show a positive trend in reducing the percentage of body fat of subjects who replace part of their LCT intake with MCT.
Figure XI. Funnel graph that evaluates the effects of MCT-conducted trials compared with LCT on body fat reduction. Negative mean (-0,x) indicates positive effect.
As an energy source
For the reasons stated above, MCTs have been proposed as an alternative energy source to traditional carbohydrates when talking about sports performance.
The subject is really very complex, because it is true that they can have a certain glycogen-saving effect.
That is, given its rapid metabolization, the intake of MCT together with carbohydrates before training can lead to some hepatic muscle glycogen being preserved in the face of increased energy availability, and it would also be a way to provide more energy substrate above 75g of glucose per hour (Jeukendrup, 2004).
Then do they preserve or do they not preserve glycogen?
Possibly in the most trained (adapted) subjects, no; but in untrained or subjects unadapted to endurance training, it may.
In any case, a large part of the studies evaluated the administration of MCT during physical exercise with negative effects, and that is that however efficient they are we should not forget that they are fats.
As such, the gastrointestinal effects of consumption during a time of reduced splenic circulation (such as during exercise) can be negative if your intestine is not adapted (a process you can also get used to).
Figure XII. The “training gut” model of the athlete as proposed by Jeukendrup.
Replace “carbohydrates” in the previous graph with “fats” and you have it.
I have not been able to find a single study that evaluated the effects of pre-training MCT consumption in subjects following a ketogenic diet.
In malabsorption disorders
People who suffer from some type of endocrine metabolic disorder that alters their ability to absorb lipids may benefit from MCT consumption relative to LCT.
There are many studies that assess the potential of these fatty acids, but you can find some of them in the Bach and Babayan review (1982).
Conditions that can benefit from MCT consumption include, but are not limited to:
- People with lipid digestion disorders (resection of esophagus or stomach, biliary atresia, obstructive jaundice, primary biliary cirrhosis, SIBO, pancreatitis, cystic fibrosis, and pancreatectomy).
- People with lipid absorption disorders (massive small bowel resection, celiac disease, Whipple’s disease, Crohn’s disease, enteritis, gluten enteropathy, and other malabsorption conditions).
- People with lipid transport disorders (congenital β-lipoprotein deficiency, intestinal lymphangiectasia, and carilluria).
Unfortunately, this does not replace the need to provide the essential fatty acids of the omega 3 and omega 6 series, nor can MCTs (or anything) replace this.
Keto Adaptation is the body’s anecdotal ability to adapt to the use of ketone bodies and fatty acids as predominant energy substrates in the absence of exogenous glucose.
This process usually takes time, and is mediated by factors such as:
- Mitochondrial biogenesis;
- Increased concentrations of intramuscular triglycerides;
- Cetolytic gene expression.
Because of this, it is not uncommon to experience symptoms of archiconocidal “keto-flu” in the first few days of a ketogenic diet, such as general malaise, apathy, and fatigue.
Symptoms go away within a few days of starting a very low-carb diet.
The use of MCT shows an inconclusive trend slowing down the symptoms of “keto-flu”; we need further studies to see if these effects are significant and homogeneous.
Figure XIII. Reports of symptoms resulting from restriction of glucose availability in the body based on fatty acids consumed.
Again, thanks to the differential metabolism of MCTs compared to LCTs, the former are structures that are widely used in cases of high caloric requirements to easily and safely increase the energy intake of subjects.
Some formulas of food preparations contain MCT, extensive use of them is not recommended since again, we require sufficient consumption of essential fatty acids by humans to avoid nutritional deficiencies.
Figure XIV. Formula of a food preparation designed for alternative nutrition.
Bigger intakes of 50g can present general distress: diarrhea, malabsorption, dyspepsia, nausea… just like when we exceed our capacity to consume simple carbohydrates.
MCT Oil in powder form from HSN
HSN have decided to produce MCT oil in powder form, specially intended for the purposes that have been previously discussed.
Are you a Keto athlete? MCT oil in powder form can’t be missing from your cupboard!
Of course, at HSN we maintain our distinctive seal of quality on every product we produce.
Did you know that most MCT oils on the market come from the palm tree?
We invite you to contact the customer services of companies that sell MCT oil without declaring its origin.
You’ll be surprised!
The problem with palm is that within its composition it contains palmic acid, which, when consumed in large quantities, transforms into a fatty acid associated with microvascular damage, dyslipidemia predisposing to atherosclerosis development and alterations in hydrocarbon metabolism which worsen sensitivity to insulin.
In this case, consumption sources of coconut fats, because of their fatty acid profile, have been shown to exert positive effects on the increase in HDL concentrations, without significantly increasing LDL concentrations (at the same magnitude as olive oil)
Improving the total Cholesterol: HDL Cholesterol ratio (Khaw et al., 2018)!
Microencapsulated with arabic gum
Powder MCTs are not easy, as they are fats, and as such their organic structure is oily.
To micronize a product with a high content of fatty acids, competitive brands use excipients that emulate fats and act as a membrane; usually caseinates and glucose and fructose syrups.
Both have problems:
- If you add caseinates, the product now contains allergens derived from milk proteins and sugars, people who are allergic to milk and/or lactose intolerant cannot use it.
- If you add glucose syrups… in a product intended for use by keto athletes… What do you think? Of course, this brings you out of ketosis.
I’ve already placed an order to try it, and what are you waiting for?
- Abe, S., Ezaki, O., & Suzuki, M. (2019). Medium-chain triglycerides (8:0 and 10:0) are promising nutrients for sarcopenia: A randomized controlled trial. American Journal of Clinical Nutrition, 110(3), 652–665.
- Babayan, V. K. (1981). Medium chain length fatty acid esters and their medical and nutritional applications. Journal of the American Oil Chemists’ Society, 58(1), 49A-51A.
- Bach, A. C., & Babayan, V. K. (1982). Medium-chain triglycerides: An update. American Journal of Clinical Nutrition, 36(5), 950–962.
- Chambers, E. S., Preston, T., Frost, G., & Morrison, D. J. (2018). Role of Gut Microbiota-Generated Short-Chain Fatty Acids in Metabolic and Cardiovascular Health. Current Nutrition Reports, 7(4), 198–206.
- Cupeiro, R. (2011). Influencia de varios polimorfismos en los genes MCT1 y CP2 sobre el metabolismo energético durante el ejercicio.
- EFSA Panel on Dietetic Products, N. and A. (NDA). (2011). Scientific Opinion on the substantiation of health claims related to medium-chain triglycerides and reduction in body weight (ID 643, 677, 1614) pursuant to Article 13(1) of Regulation (EC) No 1924/2006. EFSA Journal, 9(6), 2240.
- Goedecke, J. H., Clark, V. R., Noakes, T. D., & Lambert, E. V. (2005). The effects of medium-chain triacylglycerol and carbohydrate ingestion on ultra-endurance exercise performance. International Journal of Sport Nutrition and Exercise Metabolism, 15(1), 15–27.
- Harvey, C. J. D. C., Schofield, G. M., Williden, M., & McQuillan, J. A. (2018). The Effect of Medium Chain Triglycerides on Time to Nutritional Ketosis and Symptoms of Keto-Induction in Healthy Adults: A Randomised Controlled Clinical Trial. Journal of Nutrition and Metabolism, 2018, 2630565.
- Khaw, K. T., Sharp, S. J., Finikarides, L., Afzal, I., Lentjes, M., Luben, R., & Forouhi, N. G. (2018). Randomised trial of coconut oil, olive oil or butter on blood lipids and other cardiovascular risk factors in healthy men and women. BMJ Open, 8(3), e020167.
- Maher, T., Sampson, A., Goslawska, M., Pangua-Irigaray, C., Shafat, A., & Clegg, M. E. (2019). Food intake and satiety response after medium-chain triglycerides ingested as solid or liquid. Nutrients, 11(7).
- Mumme, K., & Stonehouse, W. (2015). Effects of medium-chain triglycerides on weight loss and body composition: A meta-analysis of randomized controlled trials. Journal of the Academy of Nutrition and Dietetics, 115(2), 249–263.
- Phinney, S. D., Bistrian, B. R., Evans, W. J., Gervino, E., & Blackburn, G. L. (1983). The human metabolic response to chronic ketosis without caloric restriction: Preservation of submaximal exercise capability with reduced carbohydrate oxidation. Metabolism, 32(8), 769–776.
- St-Onge, M. P., Mayrsohn, B., O’keeffe, M., Kissileff, H. R., Choudhury, A. R., & Laferrère, B. (2014). Impact of medium and long chain triglycerides consumption on appetite and food intake in overweight men. European Journal of Clinical Nutrition, 68(10), 1134–1140.
- Wang, Y., Liu, Z., Han, Y., Xu, J., Huang, W., & Li, Z. (2018). Medium Chain Triglycerides enhances exercise endurance through the increased mitochondrial biogenesis and metabolism. PLoS ONE, 13(2), e0191182–e0191182.
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