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- Categories of triglycerides based on the number of carbon atoms.
- Definition of Medium Chain Triglycerides (MCTs).
- Metabolism of medium chain fatty acids.
- Commonly occurring medium chain fatty acids.
- Difference between Medium Chain Triglycerides, MCT oil, Palm Kernel Oil and Coconut Oil.
- Health benefits of medium chain triglycerides.
- Which Medium Chain Triglyceride products are the best for you?
- Food sources of Medium Chain Triglycerides.
- Why are MCTs such a valuable energy source?
- Triglycerides are made up of one glycerol backbone and a random selection of three fatty acids that may vary in the number of carbons and level of saturation.
- Fatty acids within triglycerides can have a short, medium or long chain structure.
- Fatty acids can be monounsaturated, polyunsaturated or saturated.
- MCFAs refers to fatty acids with a medium chain structure of between 6-12 carbon atoms.
- LCFAs refers to fatty acids with a long chain structure or more than 12 carbon atoms.
- MCTs refer to medium chain triglycerides – oils with predominant medium chain fatty acids.
- LCTs refer to long chain triglycerides – oils with predominant long chain fatty acids.
The unique therapeutic properties of medium chain fatty acids are not new to science.
Medium chain triglycerides (MCTs) have been used for therapeutic purposes since the mid-20th century as an alternative for people who couldn’t absorb other common fats, and for people with medical conditions, such as pancreatic insufficiency or severe hyperchylomicronemia. (1)
Medium chain triglycerides have been also used to enhance the ketogenic diet effects in people with epileptic seizures.
In the 1980s, medium chain triglycerides also became a popular energy source among endurance athletes, thanks to their rapid conversion to energy.
The interest in these triglycerides has increased in recent years due to the popularization of coconut oil as a super food.
The controversy around the health benefits of high in saturated fats coconut oil continues to this day.
This article talks about the properties of medium chain fatty acids.
Categories of triglycerides based on the number of carbon atoms
Triglycerides are divided into three categories, according to the dominant length groups of the fatty acid chains:
- Short chain fatty acids (SCFAs): <6 carbons – for e.g. butyric (C4), valeric (C5)
- Medium chain fatty acids (MCFAs): 6-12 carbons (as per previous section)
- Long chain fatty acids (LCFAs): >12 carbons – for e.g. myristic (C14), Palmitic (C16), Stearic (C18).
Although each group shares similar physiological and metabolic properties inside the body, there are major differences between the groups. (read more..)
- Fatty acids are divided into three categories, depending on the number of carbon atoms they contain.
- These categories differ in their chemical, physical properties and how they are absorbed and metabolized.
Definition of Medium Chain Triglycerides (MCTs)
Medium chain triglycerides (MCTs) are saturated fat molecules composed of glycerol backbone and three fatty acids, most of which are of medium chain length. A similar principle applies for SCTs and LCTs.
There are two definitions of medium chain fatty acids, the commercial and the scientific.
- The commercial definition is based on usage
It refers to a mix of triglycerides containing predominantly fatty acids with 8 and 10 carbon atoms.
Most of the commercially used MCTs are extracted from coconut oil or palm kernel oil.
Lauric acid (12C), the major component of these edible oils, is separated due to its high commercial value in the pharmaceutical and cosmetic industries.
The remaining medium chain triglycerides, mostly Caprylic (C8) and Capric (C10), are mainly used as energy sources in various medical conditions and sports, commonly available as MCT oil (see section below).
- The scientific definition is based on the physiological properties
It refers to triglycerides containing mainly fatty acids of between 6 and 12 carbon atoms.
This definition originates from scientific studies that grouped fatty acids based on their common physiological and metabolic properties that are distinct from those of LCTs. (2)
The melting point of medium chain fatty acids is lower than that of long chain fatty acids, which explains why MCTs are liquid in room temperature while LCTs are solid.
NOTE: coconut oil is made of a mixture of MCTs and LCTs.
- Scientific definition: MCTs stands for medium chain triglycerides, which are built of fatty acids predominantly containing between 6-12 carbon atoms.
- Commercial definition: MCTs refers to a mixture of triglycerides, with mainly C8 and C10 fatty acids, commonly available as a product called MCT oil.
Metabolism of medium chain fatty acids
Most of the medium chain fatty acids are rapidly absorbed into the liver via the portal vein, where they are quickly converted to energy.
However, there are several factors that determine the specific path of this distribution: the number of carbon atoms in the fatty acid chains, the molecular mass, whether the number of carbons is odd or even, the solubility in an aqueous environment, diet and the amount of medium chain triglycerides consumed in one meal.
For these reasons, some of the longer fatty acids in the medium fatty acid category, such as lauric acid, may be sent via the lymphatic system, just like long chain fatty acids. (read more..)
- Most of the medium chain fatty acids get quickly absorbed to the liver via the portal vein and converted to energy.
- Under specific circumstances, certain medium chain fatty acids (e.g. lauric acid) may be sent via the lymphatic system, like long chain fatty acids.
Commonly occurring medium chain fatty acids
The main MCFAs are the three “capra” acids and lauric acid:
- Caproic acid (C6 – meaning six carbon atoms) also called hexanoic acid
- Caprylic acid (C8) also called octanoic acid
- Capric acid (C10) also called decanoic acid
- Lauric acid (C12) also called dodecanoic acid
The name capra means goat in Latin and refers to the abundance of these fats in goat’s milk.
Caprylic and capric acids are an excellent source of energy and are the major constituent of a well-known product called MCT oil.
They are sometimes referred to as “standard” MCFAs or MCTs, due to their connotation to MCT oil.
Lauric acid is valued more for its antibacterial properties and pharmaceutical and cosmetic applications than as nutritional medicine as a medium chain triglyceride.
- The most commonly occurring MCFAs are caproic, caprylic, capric and lauric acids
- Caprylic and capric acids have different applications than lauric acid and are often available as separate products.
Difference between medium chain triglycerides, MCT oil, palm kernel oil and coconut oil
The term medium chain triglycerides or MCTs is used interchangeably to describe either MCT Oil; two specific MCTs (C8 and C10); coconut oil; or palm kernel oil.
The following are short descriptions of these terms:
Medium chain triglycerides (MCTs) refer to a group of triglycerides with predominant fatty acids of between 6 and 12 carbon atoms (see section above).
“Standard” C8 and C10 fatty acids: caprylic (8) and capric (10) acids are the most commonly used MCTs for their efficient energy production properties.
MCT oil (almost 100% of MCTs contents): is a synthetic extract from coconut oil or palm kernel oil and contains mostly carylic (8) and carpic (10) acids. It has a small proportion of lauric acid.
Coconut oil (about 62% of MCTs contents): is naturally pressed from coconut meat. Of its total MCTs contents, it has 50% of lauric acid (C12) and only about 15% of caprylic and capric acids. The rest are mostly LCTs (both saturated and unsaturated).
Since it is a natural product with high MCTs contents, it is often referred to as a medium chain fat.
However, the fatty acids composition in coconut oil is not quite the same as in synthetic MCT products, therefore their properties, although similar, are not the same.
Palm kernel oil (about 54% of MCTs content): is extracted from the kernel of the oil palm. Of a total of 81.5% of saturated fats, it contains 47% of lauric acid, 7% caprylic and capric acids and 27.3% of LCFAs. It also has 11.4% of mono-unsaturated and 1.6% of poly-unsaturated fatty acids. (4)
Read more about the differences between MCT Oil and coconut oil.
- MCTs = saturated triglycerides with mostly 6C-12C fatty acids
- C8 and C10 = most commonly used MCTs as an energy source
- MCT oil = oil extract of almost 100% MCTs.
- Coconut oil = edible oil with 62% MCTs.
- Palm kernel oil = edible oil with 54.2% of MCTs.
Health benefits of medium chain triglycerides
The health benefits of medium chain triglycerides can be divided into two groups, depending on the specific fatty acids contents:
- “Standard”: caprylic (C8) and capric (C10) acids
The health benefits of caprylic and capric acids relate to their rapid absorption and conversion into energy and ketones and to their anti-fungal properties.
The best available source of these fats is a product called MCT oil.
- Lauric acid (C12)
Lauric acid has unique health benefits, such as anti-microbial, anti-fungal and anti-viral. Its therapeutic properties are related to monolaurate and polyphenols.
The best and most widely used source of lauric acid is coconut oil.
- Caprylic, capric and lauric acids contribute to most of the health benefits of medium chain fatty acids.
- The range of health benefits differ, depending on the type of fatty acid used.
Which medium chain triglycerides products are best for you?
MCT Oil (or C8 and C10 fatty acids) is the most researched and widely used medium chain fatty acid source.
It has a long history of therapeutic usage and is the most commonly used medium chain triglyceride product in clinical trials.
It is suitable for therapeutic purposes for individuals with lipid metabolism complications or type 2 diabetes. (see medicinal uses of MCT oil).
Most of the fatty acid chains in this product have 8 and 10 carbons, which explains the low smoke point and why they are not stable enough to use in cooking (frying) – they oxidize rapidly.
MCT oil has a very mild taste and, therefore, works well as a supplement or added to your food.
Since it converts immediately into energy, it is an ideal substitute for glucose in sports for those who are in a low carb diet.
NOTE: it is recommended not to exceed 25-30g per meal to avoid unpleasant symptoms, such as diarrhea or nausea.
Lauric acid is mostly used for in the pharmaceuticals and cosmetics industries, due to its antibacterial properties.
It has shown to destroy viruses and gram-negative bacteria and have anti-fungal properties.
Coconut oil and palm kernel oil on the other hand, are suitable for cooking because of the longer chains of their fatty acids – Lauric acid (C12) and LCTs of over 12 carbons. Therefore, they are more stable in higher temperatures.
Although these oils are ideal for shallow frying, they are not recommended for continuous deep frying, due to a low smoke point.
Since these oils have distinctive flavors, they may not be suitable for everyone.
If not used for frying, coconut oil is a great addition to many foods, such as breakfast cereals, salads and soups.
- Coconut oil and palm oil are convenient and tasty oils that can be used for cooking.
- MCT oil is a concentrated supplement with a potent effect as an energy nutrient.
- To avoid adverse side effects, such as diarrhea or nausea, limit the dose of any MCTs to 25-30g in one meal.
Food sources of Medium Chain Triglycerides
The most abundant source of MCTs is a synthetic product called MCT oil.
It is almost tasteless and best used as a supplement, added to ready to eat food.
Natural food sources
Coconut oil is the richest food source of MCTs (about 62%).
Although most of the coconut’s medium chain acids are lauric acid, it is still one of the best food sources of capra acids.
Overall the richest dietary sources of MCTs are:
- Coconut oil
- Coconut meat
- Palm kernel oil
- Goat cheese
- Other full cream dairy products (milk, yogurt, cheese)
NOTE: For the full list of MCT rich foods, please see “Food sources of medium chain triglycerides”
- The best food sources of MCTs are coconut oil, palm kernel oil, goat cheese and dairy fat products, such as butter, cheese, full cream milk, and yogurt.
- The best supplement with MCTs is a C8 and C10 extract called MCT oil.
Why are MCTs such a valuable energy source?
There are nutrients that produce energy: carbohydrates, fat and protein.
Energy production is not the primary function of proteins.
They are primarily used for other functions, such as in structural components, to aid in transporting small molecules, as antibodies, in enzymes and as messengers (e.g. hormones). (5)
Although protein can be converted into energy, the conversion process is not efficient. The body only treats protein as an energy source in the starving mode, where body fat is being spared.
Carbohydrates provide an immediate source of energy.
However, a diet high in simple carbohydrates is the major cause of insulin resistance, obesity, type 2 diabetes, increased risk of cardiovascular disease and other serious health conditions.
On the other hand, a diet high in complex carbohydrates may be not suitable for people sensitive to carbohydrates. They tend to have a more drastic insulin response and are more prone to weight gain, because of the way they metabolize carbohydrates.
If you are on a ketogenic diet, your body uses LCTs to produce ketone bodies that are used as energy by the body cells.
Otherwise, (on the diet based on carbohydrates) long chain triglycerides undergo a complex absorption and metabolic process and most end up as energy storage in fatty cells.
Medium chain triglycerides, thanks to their quick absorption and metabolism, are rapidly converted into energy, just like sugar.
The advantage is that, unlike glucose, they don’t cause insulin spikes, and unlike fructose they don’t cause liver damage. (read more..)
Most MCTs are converted into energy and only a small percentage gets stored in the fatty cells. This is the reason why they an excellent energy source.
- MCTs are a better energy source than sugars because, although they produce energy almost immediately after absorption like sugars, they don’t cause insulin spikes.
- MCTs are a better source of energy than LCTs because most get converted to energy, while most LCTs are stored in the fatty tissues.