Medium chain triglycerides (MCT) have chains of fatty acids with a length of 6 to 12 carbon atoms (1). There are both synthetic and natural MCTs in the world. Natural sources include coconut oil, palm kernel oil and milk fat. (2).
- Types of MCT
- 1) MCTs have antibacterial and antiviral effects
- 2) MCT helps in weight loss
- 3) MCT increases exercise performance
- 4) MCT helps in diabetes
- 5) MCT - benefits for the brain
- 6) MCTs increase muscle strength in the elderly
- 7) MCT increases the effect of fish oil
- Side effects
- The mechanism of action
Types of MCT
There are three main types of MCTs that we can distinguish based on their length
- caproic acid is 6 carbon atoms long,
- caprylic acid is 8 atoms long,
- capric acid has a length of 10 carbon atoms,
- there is still lauric acid, however many sources describe it as LCT has a length of 12 carbon atoms.
The amount of each type depends on the source (3). In the past, MCT has been used to treat digestive problems such as pancreatic insufficiency, fat absorption disorder, and severe hyperchylomicronemia (4). MCT has been considered safe by the FDA for human consumption more than 20 years ago (5).
1) MCTs have antibacterial and antiviral effects
One type of MCT, lauric acid, is better at killing bacteria and viruses than caprylic acid or capric acid (6). In neonates, both MCT and medium-chain fatty acids (MCFAs) derived from breast milk had antimicrobial activity in the gastrointestinal tract and decreased pathogen transmission (7). It has also been shown that MCT and MCFA reduce the growth of some species of Malassezia, an infectious fungus commonly found in hospitals (8).
MCT studies in rats showed better intestinal integrity, modulation of immune response and better secretion of antibodies (9) in the gut. In MCT piglets, they reduced intestinal pH, modulated intestinal microenvironment, and potentially prevented diarrhea after weaning (10).
2) MCT helps in weight loss
One study in overweight men found that MCT compared to long-chain triglycerides (LCT) led to decreased appetite and increased satiety (11).
A diet rich in MCT also contributed to a greater fat burning and loss of body fat compared to a diet rich in LCT. It was also indicated that this effect may decrease after the organism has adapted, after about 2-3 weeks (12). Several other studies in animals and humans have shown that MCT (caprylic and capric) increases the body's ability to burn fat and calories (13).
It has also been found that a diet rich in MCT contributes to reducing the consumption of fat and calories. The study was conducted on 36 healthy women (14). MCTs can increase the feeling of fullness or fullness, which leads to reduced food intake and causes weight loss (15). They are decomposed faster than LCT, thanks to which they are easier to use by the body and are less frequently transformed and stored as fat (16).
In humans, consumption of MCT for 4 weeks resulted in increased energy expenditure, fat loss and weight loss (17). MCT oils can be incorporated into weight-loss programs without any adverse effect on metabolic health (18). Analysis of the experiments showed that after 3 weeks of MCT consumption, the majority of participants had decreased body weight, waist circumference, hip circumference, total body fat percentage, total subcutaneous fat and visceral fat compared to LCT (19).
Studies conducted on cells have shown that MCT reduces the conversion of excess carbohydrates to fats (20).
3) MCT increases exercise performance
A study in mice showed that in swimming tests they were much better when fed a diet rich in MCT compared to a diet rich in LCT (21). It has also been shown that eating foods containing MCT instead of LCT for 2 weeks increases the time of high-intensity exercise in recreational (non-professional) athletes (22).
4) MCT helps in diabetes
One study found that diets rich in MCT increase insulin sensitivity in adults with type 2 diabetes (23). Another study in people with type 2 diabetes has shown that MCT supplementation has improved the risk factors for diabetes, as well as decreased body weight, waist circumference, and insulin resistance (24). However, in one study, MCTs resulted in significantly higher levels of glucose in the blood (25).
5) MCT - benefits for the brain
MCT has been shown to improve the process of learning, memorizing and information processing in the brain in people with mild to moderate Alzheimer's disease, although this was noticed only in those who had the APOE4 gene (26). They have also been shown to improve memory compared to placebo in subjects with mild cognitive impairment (27).
One of the studies showed an improvement in cognitive functions, especially of women, people without type 2 diabetes and heavy patients (28).
6) MCTs increase muscle strength in the elderly
7) MCT increases the effect of fish oil
A rat study showed that MCT and MCFA increase the beneficial effects of fish oil on the heart (30). The concentration of EPA and DHA in the serum was significantly elevated in MCT-fed rats (31) enriched with fish oil.
Nausea, stomach cramps and other intestinal problems are a known side effect of MCTs (32).
A single dose of MCT in the range of 5 to 50 g or a weekly diet containing 40% MCT fat systematically leads to increased post-meal oxygen consumption and thermogenesis, increased total fat oxidation, higher energy expenditure and reduced energy storage compared with LCT administered under identical conditions (33).
The mechanism of action
MCTs are absorbed directly into the portal vein, rapidly transported to the liver for beta-oxidation, and thereby cause diet-induced heat production compared to long-chain triacylglycerols, which are absorbed through the intestinal lymphatic channels and transported by chylomicrons through the thoracic duct into the systemic circulation (34).