MCTs stands for medium-chain triglycerides, a type of fat. They're found naturally occurring in foods like coconut oil and palm kernel oil. MCTs can be extracted food to make MCT oil. They're less likely to be stored as fat as your body finds them easier to break down and use. They're claimed to help with weight loss, cholesterol levels, brain function, and exercise performance. But more research is needed to understand if they're beneficial for your health.

What are MCTs?

MCTs stands for medium-chain triglycerides, a type of fat. MCTs are made up of 2-3 fatty acids and contain a tail of 6-12 carbon atoms. Most fats in your diet are long-chain triglycerides (LCTs)— these have a tail of 13–21 carbon atoms.

The main MCTs are:

  • caproic acid — contains 6 carbons
  • caprylic acid — contains 8 carbons
  • capric acid — contains 10 carbons
  • lauric acid* — contains 12 carbons

*A lot of the possible benefits of MCTs don’t apply to lauric acid as they behave more like LCTs. So there’s some debate as to whether lauric acid should be classified as an MCT. Many experts believe it should only include fats with 6-10 carbons.

Forms of MCTs

MCTs are found naturally occurring in some foods, including coconut oil, palm kernel oil, whole milk, and butter. MCTs can also be extracted from food to create a supplement like MCT oil.

Coconut oil often is claimed as a great source of MCTs. But as it contains mostly lauric acid (about 47%), many of the benefits related to MCTs don’t apply to commercial coconut oil. 

What happens when you consume MCTs?

Because of their shorter chain length, your body finds it easier to break down and absorb MCTs. These go to your liver and can be used instantly for energy or turned into ketones. Unlike other fatty acids, ketones can pass from your blood to your brain — which can act as an energy source for your brain. Although your brain’s preferred energy source is still glucose.

Since MCTs can be used as an energy source first, it means they’re less likely to be stored as fat. Of course, if you have too much MCTs, they’ll eventually be stored as fat.

Can MCTs help with weight loss?

It’s been claimed that MCTs can help aid weight loss by increasing fullness and how many calories you burn. They’re also almost 10% lower in calories than LCTs. But research focusing on MCTs as a weight loss aid is very mixed. 

Some studies show that it might help aid weight loss, with the biggest benefit seen in men and people who started with a high amount of body fat. But even in these cases, the effects tended to be quite modest. Other studies show no effect.

Many of these studies involve small sample sizes. And some haven’t accounted for other important factors, like how much you exercise or how many calories you eat — which hugely influence weight loss. 

So, in a nutshell, more research is needed before any recommendations can be made about using MCTs to aid weight loss.

Do MCTs have other health benefits?

MCTs have been used for years to help treat malnutrition and conditions that cause food absorption issues, like:

  • coeliac disease
  • cystic fibrosis
  • liver disease
  • gallbladder disease

MCTs are sometimes used in the treatment of childhood epilepsy — taken as part of a ketogenic diet.

Brain function
If you have Alzheimer’s disease, it can affect your brain’s ability to use sugar as an energy source. With MCTs, it offers your brain an alternative energy source, ketones. So some research shows that it might help protect your brain in the early stages of Alzheimer’s disease. But these benefits only seem to be found in people with the APOE e4 gene variant.

Cholesterol levels
Some research shows that MCTs might help lower cholesterol levels. Other studies show the opposite. Again, these studies tended to have small sample sizes and sometimes used coconut oil (high in lauric acid) as the source of MCTs. Plus, many of the findings come from animal studies. So, larger-scale human studies are needed to understand the relationship between MCTs and cholesterol better.

Exercise performance
Some research shows that MCTs might help to increase exercise performance — by improving your energy and endurance. But most of the research so far shows no benefit. More high-quality research is needed to understand this relationship better. 

Diabetes
MCTs might help to lower blood sugar levels and increase insulin sensitivity. Again, this has only been demonstrated in studies using animals or small sample sizes. 

Some experts advise against people with type 1 diabetes taking MCTs due to the increased risk of ketoacidosis — very high ketone and blood sugar levels. But, ketoacidosis caused by your diet is quite different from diabetic ketoacidosis. Since this is still unclear, and due to the seriousness of ketoacidosis if you have type 1 diabetes, it’s better to err on the side of caution.

Should you take MCTs?

Aside from their use to help treat conditions like malnutrition, research has a long way to go to support claims around the benefits of MCTs. Conflicting studies, small sample sizes, and lack of human studies mean we can’t draw any clinically relevant conclusions yet.

It’s also really important to look at the bigger picture. For example, if you’re eating a highly-processed diet, MCTs won’t negate these effects. Many factors contribute to your health and your risk of developing chronic conditions. It’s important not to just focus on one thing.

Is there a recommended dose for MCTs?

If MCTs do in fact provide these benefits, it’s not clear what dose you need. Most studies have tended to use between 1-5 tablespoons of MCT oil. It’s also a good idea to talk to a health professional before starting any supplement.

If MCTs are being used in the treatment of certain medical conditions, a trained health professional will decide on the appropriate dose.

Do MCTs have any side effects?

As mentioned, there are some questions around the safety of MCTs if you have type 1 diabetes. But in general, MCTs are likely safe for most people.

MCTs can sometimes cause diarrhoea, nausea, vomiting, and stomach discomfort. So if you do take them, starting with a low dose and taking them with food is recommended.

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References

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Page, K. A., Williamson, A., Yu, N., McNay, E. C., Dzuira, J., McCrimmon, R. J., & Sherwin, R. S. (2009). Medium-chain fatty acids improve cognitive function in intensively treated type 1 diabetic patients and support in vitro synaptic transmission during acute hypoglycemia. Diabetes, 58(5), 1237-1244.

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Aisling Moran BSc (Hons)

Written by Aisling Moran BSc (Hons)

10th Aug 2020 • 7 min read