MCT oil

As the name suggests, MCT oil (where MCT stands for medium-chain triglycerides) contains fatty acids with a shorter fatty acid chain length than most other dietary fats, which primarily contain long-chain fatty acids. Because of their shorter length, MCTs are easily and quickly digested and many of the health benefits attributed to these fatty acids are related to the way the body processes them. MCT oil is usually extracted from coconut oil, more than 50% of whose fat consists of medium-chain triglycerides. However, these fats are also found in other foods such as palm oil and dairy products (1).

There are four different types of MCTs, of which caprylic acid and capric acid are the most commonly used variants in MCT oils. In some cases, these specific types of MCT oils have their own benefits.

MCT oil is an excellent source of energy. The molecules of this oil are too short to be stored as fat, meaning it circulates in the body until it is used up. MCTs release more than twice as much energy as glucose. Although MCTs consist of pure fat, they do not have to undergo any complicated digestive pathways like long-chain fatty acids. Due to their water solubility, they do not require fat-splitting enzymes and can be absorbed quickly in their original form. MCTs pass through the liver directly into the mitochondria and are burned there, even if the cell is already filled with carbohydrates. This is one reason why MCTs are not stored as body fat. MCT oil is particularly recommended during a diet. MCTs protect the muscles from protein breakdown. This means that an athlete has more protein available for regeneration and further muscle building during a diet and after hard training. Ketones also suppress the appetite. When MCTs are metabolized, some of them are burned as heat, which can result in an increase in body temperature. This can speed up the metabolism. MCT oil provides enough energy for a massive build-up.

MCTs do not increase cholesterol or blood lipid levels

"Obviously a diet with MCTs does not lead to the dreaded yo-yo effect", claims Birgit Junghans from the German Institute of Nutritional Medicine and Dietetics (D.I.E.T.) in Bad Aachen. The yo-yo effect has to do with the fact that the body adjusts to a lower basal metabolic rate during a slimming diet and then maintains this when eating "normally" again. However, a normal diet with a reduced resting metabolic rate inevitably leads to weight gain. And anyone who has lost ten kilograms during the diet can all too easily suddenly gain twelve kilos seven or eight months after the end of the slimming diet. And it is precisely this yo-yo ordeal that MCT is supposed to prevent.

A study conducted by the Fourth Internal Clinic of the Faculty of Medicine at the University of Prague produced the following results: 30 test subjects who were given a reduction diet (very low calorie diet) with 380 kilocalories a day and an additional 15 milliliters of MCT oil with an energy content of 125 kilocalories lost the same amount of weight as the participants in the control group, who also followed the reduction diet but were not given any additional MCT. Despite the higher energy intake of 125 kilocalories due to the MCT oil, the energy consumption at rest did not decrease in contrast to the group without oil intake! According to study leader Dr. Vojtech Hainer, this indicates that the dreaded yo-yo effect of dieting cannot occur if the fat consumed contains medium-chain fatty acids. "This is because when MCT fats are used, the basal metabolic rate does not fall during the diet," says German nutritionist Junghans. "A reduction diet in which normal fats, including high-quality oils such as olive oil and rapeseed oil, are replaced by margarines, salad oils and spreads containing MCTs and which otherwise provides plenty of carbohydrates and fiber, is more promising in the long term than any diet before it."

The special (health) benefits of MCT oil

1. MCT oil promotes fat loss in several important ways

There are several reasons why MCT oil can be beneficial when you are trying to lose weight. This starts with the fact that MCT oil has been shown to increase the release of two hormones that increase satiety: peptide YY and leptin (2). MCT oil could be even better than coconut oil when it comes to satiety. One study found that people who consumed two tablespoons of MCT oil as part of their breakfast ate less at lunch compared to people who consumed the same amount of coconut oil (3). The same study also showed a lower increase in triglyceride and blood glucose levels when using MCT oil, which further promotes satiety.

In addition, it has been shown that taking MCT oil can significantly reduce body weight and waist circumference. Scientists even report that it can help prevent obesity (4, 5, 6). MCT oil has about 10% fewer calories than long-chain triglycerides found in other foods such as olive oil, nuts and avocados (7, 8). The body also processes MCTs differently, which may help burn more calories (4, 9, 10). MCT oil can be converted into ketones, which are produced during the breakdown of fat when carbohydrate intake is low. If you are following a ketogenic diet, which is very low in carbohydrates and high in fat, using MCT oil can help you stay in a fat-burning state known as ketosis.

Last but not least, your gut flora is very important when it comes to your body weight. MCT oil can help promote the growth of good gut bacteria and support the health of the gut wall, which could help you lose weight (11).

Summary: MCT oil may support weight loss by increasing satiety, increasing energy expenditure and improving gut flora.

2. MCT oil is an instant source of energy that can be used to fuel the brain

MCTs are known as a super energy source because the body can absorb MCTs faster than long-chain triglycerides, which contain more carbon atoms in their fatty acid chains (7). Due to the shorter fatty acid chains, MCTs reach the liver directly and do not have to be broken down like long-chain fatty acids (12). In the liver, the fats are broken down and either used as an energy source or stored in the form of body fat. As MCTs can easily enter the cells without being broken down, they can be used as an immediately available source of energy (13).

If you follow a ketogenic diet, MCTs can also be converted into ketones in the liver. These ketones can cross the blood-brain barrier and serve as an energy source for brain cells.

Summary: MCT oil is easily absorbed by the body and can be easily transported to any location within the body. It can be used as an immediately available energy source or converted into ketones that can energize your brain.

3. MCT oil can help prevent lactic acid accumulation in athletes and help utilize fat as an energy source

MCTs are very popular with athletes. During exercise, rising lactic acid/lactate levels can impair exercise performance. Interestingly, MCT oil can help reduce this lactic acid accumulation. One study found that athletes who consumed 6 grams, or about 1.5 teaspoons, of MCT oil with food before a cycling workout had lower lactate levels and perceived the workout as subjectively easier compared to athletes who consumed long-chain triglycerides (14). In addition, this study found that taking MCT oil before exercise could help increase the use of fats instead of carbohydrates as an energy source. However, although MCTs can increase fat burning during exercise, the study results on whether MCT oil can help increase exercise performance are mixed (15).

One study showed that MCT oil could increase swimming capacity in mice, but a human study did not show any improvement in endurance in runners (16, 17). At least the results of an animal study suggest that MCT oil does not affect exercise performance, which is encouraging (18).

Summary: MCT oil can increase fat burning and reduce carbohydrate requirements during exercise. However, it is unclear whether this translates to better exercise performance.

4. MCT oil could help people cope better with epilepsy, Alzheimer's and autism

Studies have shown that MCT oil and a ketogenic diet could help patients cope better with conditions such as epilepsy, Alzheimer's and autism (19).

Epilepsy

Although a ketogenic diet is popular with people who want to lose weight, it was first used as a way to control epilepsy. Scientists had found that fasting increases the production of ketones and these can reduce the frequency of epileptic seizures (20). Since MCTs can be converted into ketones, they could be beneficial in controlling epilepsy. However, the type of MCTs may be important here. A test tube study has shown that the MCT fatty acid capric acid is better at controlling seizures than a widely used epilepsy drug (21). A study conducted in rats found that the same MCT fatty acid blocks the receptors in the brain that cause seizures. However, further human studies are needed for a definitive conclusion (22). Additionally, it is important to note that a ketogenic diet is not suitable for everyone and can be challenging in the long term (23). If you are considering using a ketogenic diet to support epilepsy treatment, you should discuss this with your doctor or dietitian beforehand.

Alzheimer's disease

Alzheimer's disease impairs the brain's ability to use glucose (24). However, an MCT-rich ketogenic diet provides an alternative source of energy: ketones. This allows brain cells to survive better and ketones also block a receptor in the brain that causes memory loss (19). One study found that a single dose of MCTs improved short-term memory in 20 patients suffering from APOE ɛ4-negative Alzheimer's disease (25). Even if genetic factors play a role, there is evidence that 20 to 70 grams of supplemented MCT oil containing caprylic acid or capric acid can slightly improve the symptoms of mild to moderate Alzheimer's disease (24).

All in all, the benefits of MCT oil in the treatment of Alzheimer's are promising, but further, larger studies are needed (25).

Autism

MCT oil may also help children with autism (26). One study observed positive overall improvements when a ketogenic diet was followed for 6 months (27). Another study found that adding MCT oil to a ketogenic and gluten-free diet substantially improved autism behaviors in 6 out of 15 children (26). As autism is a disease with a wide range of symptoms, it can affect different people differently. This means that adding MCT oil to the diet may have varying effects or no effect. Here too, further scientific research is needed (28). The use of a ketogenic diet as an adjunctive treatment for autism should also be discussed in advance with the treating physician.

Summary: MCT oil could improve brain function, which could have positive effects on people suffering from epilepsy, Alzheimer's or autism.

5. MCT oil contains fatty acids that could fight the growth of yeast and bacteria

MCT oil has been shown to have antimicrobial and antifungal effects (29, 30, 31). Studies have shown that coconut oil, which contains large amounts of MCT oil, can reduce the growth of Candida albicans by 25%. This is a widespread yeast fungus that can cause various skin infections (32). A test tube study also showed that coconut oil can reduce the growth of a pathogenic bacterium called Clostridium difficile (30). MCT oils themselves have been shown to reduce the growth of a common fungus in hospitals by up to 50% (33).

However, it is important to note that most research on MCTs and immune support has been conducted in test tubes or with animals. High quality human studies are needed before final conclusions can be drawn.

Summary: MCT oil contains fatty acids that have been shown to reduce the growth of yeast and bacteria. Overall, MCTs have a variety of antimicrobial and antifungal effects.

6 MCT oil could reduce risk factors for heart disease such as obesity and elevated cholesterol levels

Heart disease is a growing problem in the Western world. Some factors that can increase the risk of these diseases are high cholesterol levels, high blood pressure, inflammation, obesity and smoking. MCT oil has been shown to support weight and fat loss. In turn, this could help reduce the risk of heart disease (1). A study of 24 overweight men found that taking MCT oil in combination with phytosterols and linseed oil over a 29-day period reduced total cholesterol levels by 12.5%. When olive oil was used instead of MCT oil, the reduction was only 4.7% (34). The same study also observed better reductions in "bad" LDL cholesterol levels when the MCT oil blend was added to the diet. In addition, MCT oil can also increase the production of heart-protective "good" HDL cholesterol (35).

MCT oil can even significantly reduce levels of C-reactive protein, an important inflammatory marker that increases the risk of heart disease (36). In addition, studies have found that MCT oil-based mixtures may have a positive effect on other risk factors for heart disease (37, 38).

Summary: MCT oil may reduce risk factors for heart disease such as weight, cholesterol levels and inflammation. Adding this oil to your diet could help reduce your risk of heart disease.

7. MCT oil could help control your blood sugar levels and support diabetes management

MCT oil may also have benefits for diabetics (39). Most people who suffer from type 2 diabetes are overweight or obese, which makes it harder to control diabetes. However, MCTs have been shown to reduce fat storage and increase fat burning (40). A small Chinese study of 40 diabetics found that those who consumed MCTs daily experienced significant reductions in body weight, waist circumference and insulin resistance compared to subjects who consumed corn oil (which primarily contains long-chain fatty acids) (39). Another study of 10 subjects found that diabetics who injected insulin required 30% less sugar to maintain normal blood glucose levels when they consumed MCTs instead of long-chain fats (41). However, the same study found no effect of MCTs on reducing fasting blood glucose levels.

Summary: MCT oil could support diabetes management by reducing fat storage and increasing fat burning. It may also help to control blood glucose.

Need in sports

Athletes often use MCT oils as a reliable source of energy before training. This supplies the body with quickly usable energy and at the same time prevents the accumulation of unused substance in the form of fat reserves. The increased thermogenesis even causes fat loss!

Replace as much of your cooking oil or fat as possible with MCT. It is suitable for cold dishes, such as salads or mixed drinks, as well as for cooking, baking and light frying. Athletes should take approx. 10 to 100 ml of MCT (slowly increasing the dose) about 30 minutes before training in order to achieve an additional energy boost. It is recommended to take them together with muesli or as a mixed drink with fruit or vegetable juice or a protein drink. However, MCT oils are not suitable for frying and must not be heated above 130 degrees Celsius!

Potential disadvantages of MCT oil

Even though MCTs are considered safe, they can have some disadvantages (42).

MCTs could stimulate the release of hunger hormones

Although MCTs can increase the release of hormones that can help you feel fuller for longer, they may also stimulate the release of hunger hormones in some people (2, 43, 44).

A study conducted with subjects suffering from anorexia found that MCTs increased the release of two hormones that stimulate appetite: Ghrelin and neuropeptide Y (45). Subjects who consumed more than 6 grams of MCTs per day produced greater amounts of these hormones than those who consumed less than 1 gram of MCTs per day.

However, it is unclear whether increasing the levels of these hormones actually causes you to eat more.

High doses of MCTs could lead to fat deposits in the liver

High doses of MCT oil could increase the amount of fat in the liver in the long term. A 12-week study conducted on mice found that a diet consisting of 50% MCT fats increased liver fat. Interestingly, the same study found that MCTs reduced total body fat and improved insulin resistance (46). However, it should be kept in mind that high doses of MCT oil, as used in the above study, are not recommended. Overall, further research is needed to draw conclusions about the long-term effects of MCT oil. MCTs are high in calories and should only make up 5 to 10% of your total calorie intake. If you are trying to maintain your weight or lose weight, you should consume MCT oil as part of your total fat intake and not as additional fat.

Summary: MCT oil increases the release of hunger hormones, which could lead to increased food intake. In the long term, it could increase the amount of fat in the liver.

Safety and side effects

MCTs are safe and harmless for most people when taken orally or intravenously. They can cause diarrhea, nausea, vomiting, irritability, stomach upset, bloating, essential fatty acid deficiency and other side effects. Taking MCTs with food may reduce some side effects.

Precautions and warnings

Pregnancy and lactation: Not enough is known about the safety of MCTs during pregnancy and lactation. For this reason, pregnant and breastfeeding women should avoid MCTs to be on the safe side.

Diabetes: MCTs can cause a build-up of chemicals called ketones in the body. This can be a problem for diabetics. For this reason, diabetics should avoid MCTs.

Liver problems: Because MCTs are primarily processed by the liver, they can cause serious problems for people suffering from liver disease. For this reason, MCTs should not be used if you suffer from cirrhosis or other liver problems.

Conclusion

Consuming MCT oil could have many benefits with minimal risks. First of all, MCT oil contains fatty acids that can promote weight loss by reducing body fat, increasing satiety and potentially improving gut flora.

MCTs are also an excellent source of energy and could combat bacterial growth, help promote heart health and help better control diseases such as diabetes, Alzheimer's, epilepsy and autism.

Potential downsides could include increased hunger and possible fat deposits in the liver. However, as long as the amount consumed is kept at 1 to 2 tablespoons per day and MCTs are used to replace other fats, negative side effects are unlikely. At the end of the day, MCT oil is a convenient way to take advantage of all the health benefits MCTs have to offer.

References

Further studies

Kono H, Fujii H, Asakawa M, Yamamoto M, Matsuda M, Maki A, Matsumoto Y. Protective effects of medium-chain triglycerides on the liver and gut in rats administered endotoxin. Ann Surg. 2003 Feb;237(2):246-55
Krotkiewski M. Value of VLCD supplementation with medium chain triglycerides. Int J Obes Relat Metab Disord. 2001 Sep;25(9):1393-400
St-Onge MP, Jones PJ. Physiological effects of medium-chain triglycerides: potential agents in the prevention of obesity. J Nutr. 2002 Mar;132(3):329-32
Van Zyl CG, Lambert EV, Hawley JA, Noakes TD, Dennis SC. Effects of medium-chain triglyceride ingestion on fuel metabolism and cycling performance. J Appl Physiol. 1996 Jun;80(6):2217-25
Angus DJ, Hargreaves M, Dancey J, Febbraio MA. Effect of carbohydrate or carbohydrate plus medium-chain triglyceride ingestion on cycling time trial performance. J Appl Physiol. 2000 Jan;88(1):113-9
St-Onge MP, Lamarche B, Mauger JF, Jones PJ. Consumption of a functional oil rich in phytosterols and medium-chain triglyceride oil improves plasma lipid profiles in men. J Nutr. 2003 Jun;133(6):1815-20
Traul KA, Driedger A, Ingle DL, Nakhasi D. Review of the toxicologic properties of medium-chain triglycerides. Food Chem Toxicol. 2000 Jan;38(1):79-98