Cross-posted from Dietitian at Home.
Apparently there is nothing coconut oil cannot do. According to innumerable health and lifestyle sites, it’s good for the body inside and out; you’ll never need another fat again. There’s so much hype and beautiful, flowery language around this food that it is really difficult to know what is true, and what is a bit (or an extreme amount) of exaggeration about the virtues of this wonder fat. This article makes some pretty bold assertions, and always, extraordinary claims require extraordinary evidence.
But first, a primer on coconut oil. Despite its name, it is a fat that is solid at room temperature. This is due to the fact that it contains 90% saturated fatty acids, which is more than butter. What sets it apart from most other solid fats is the types of saturated fats in coconut oil. Fatty acids – the components of “fat” – are strings of carbon atoms with a certain number of hydrogen atoms attached, with or without double bonds. Saturated fatty acids have no double bonds; this is what allows them to fit together compactly, making a solid fat. Fatty acids come in many lengths, from 4-carbon chains all the way up to 22 carbons, occasionally more. Most of the saturated fats in butter or animal fats are long-chain, 16 to 20 carbons atoms. Of coconut oil’s 90% saturated fat content, 58% of those fatty acids are medium chain triglycerides (MCTs), 6-12 carbons per chain. These fats are metabolized differently than long fatty acids, and this is a key point to remember when examining the health claims. Interestingly, coconut oil contains no omega-3 fats, the polyunsaturated fats most associated with reduced cardiovascular disease risk. Even butter contains 1% omega-3 fats.
So on to the health claims (paraphrased):
1. Coconut oil has a unique fatty acid composition with medicinal properties.
Yes, it has a unique composition, just like every other fat out there. We wouldn’t expect coconut oil to be exactly like butter, because then it would be butter. The medicinal properties claim comes from the high proportion of MCTs. MCT oil is regularly used in medical nutrition therapy for many conditions including malnutrition, malabsorptive disorders, the ketogenic diet for seizures and other brain disorders, and more. It is a manufactured product, meant to ensure purity, potency, and almost exclusive MCT content. Any health benefits from coconut oil cannot be fairly equated to those of MCT oil because they are very different substances. MCTs do have a beneficial effect on the conditions listed above, however, we cannot extrapolate that people without these conditions would see the same benefits.
2. The people who eat the most coconut oil are the healthiest.
This is another epidemiological finding that cannot imply causation. Both the groups pointed out, the Tokelauans and the Kitavans are small, isolated populations, living largely subsistence lifestyles, with almost no intake of western refined foods. There are so many differences between their genetics predispositions, activity levels, lifestyles, and diet compared to ours in North America that to conclude their apparent reduced incidence of cardiovascular disease is due to coconut oil is unfair at best, deceptive at worst.
3. Coconut oil will help you burn fat, lose weight.
Right now there is not enough evidence to make this assertion. It doesn’t mean it’s not true, or that coconut oil does not have a favourable effcect compared to other fats, it’s just that the research hasn’t been done. A lot of the articles cited in support of this claim, like this one, this one, and this one are very small (12 or fewer subjects each) and completed 20-30 years ago. Small sample size reduces the strength of the evidence, so no big conclusions can be made. And again, some of these studies used MCT oil, not coconut oil; strike two against this claim.
4. Coconut oil has antimicrobial effects.
Most of the studies cited to support this claim are in vitro studies, a.k.a. put-things-in-a-petri-dish-and-see-what-happens study. We learn a lot from this kind of research, it’s what gives us a better understanding and generates many more research hypotheses. But this type of research absolutely cannot be used to make recommendations about human health and interventions. The reason is simple: the human body is not a petri dish. Our bodies are not tightly controlled environments where only one variable is manipulated at a time. Using in vitro studies to make a health claim is like saying that we are made of atoms, atoms are mostly space, thus we are invisible. An interesting idea, but clearly false. Luckily, a better in vivo (in a living being in semi-normal conditions) study was done to test the antimicrobial claims of coconut oil but sadly, the beloved tropical fat didn’t do any better than controls. Please, please, please, if you suspect you have any type of infection, skip the coconut oil and talk to your doctor.
5. Coconut oil can reduce hunger (…thus helping you lose weight).
Just like the previous weight loss claim, the studies cited are old and small, the test diets are very different from typical diet patterns, and once again, they are using MCT oil, not coconut oil. I’m not saying there’s no benefit to coconut oil here, there just isn’t enough good evidence to support that.
6. MCTs in coconut oil are helpful for seizure control, as part of the ketogenic diet.
I feel like we’ve covered this already…but here it goes again. Yes, the high fat ketogenic diet, with or without MCTs, is a very useful treatment for some people with significant neurological disorders. If you do not have a condition like that, this “benefit” does not apply to you. As always, the claimant is conflating concentrated MCT oil with coconut oil. If you or a loved one do love with a condition for which the ketogenic diet may be prescribed, listen to the advice of your health care team and ignore this claim all together. Ultimately, this claim helps no one and may cause harm to someone who thinks they will get a health “boost” from switching to coconut oil. This is a dangerous path to take.
7. Coconut oil improves blood cholesterol levels, especially the “good” cholesterol HDL.
This is probably one of the best researched topics in the usefulness of coconut oil at present. Coconut oil does seem to show some favourable effects on cholesterol levels and types. What this tells us is that coconut oil is likely safe and can be part of healthy diet. This does not tell us that we should eschew all other oils and use coconut oil exclusively for all of our fat-based needs.
8. Coconut oil can be used as sunscreen and moisturizer.
Sunscreen can also be used as sunscreen. Coconut oil’s impressive-sounding ability to block out 20% of UV rays is no match for your run-of-the-mill SPF 15 sunscreen which blocks 93% of those rays. As for moisturizer, plant-based oils and fats have been used – and continue to be – for centuries as moisturizers. Cocoa butter, shea butter, and coconut oil tend to be favourites because of the nice smells and smooth, not oily textures. This likely has to do with the MCTs and their low melting point, but I can’t be sure and I’m too tired to keep talking about this. Moving on.
9. Coconut oil can improve Alzheimer’s.
False. Hear-say and case-studies do not equal evidence. Next claim.
10. Coconut oil can help you lose dangerous belly fat.
See the items above for weight loss. There is some research showing that coconut oil may in fact have this positive effect, but as usual, no conclusions should be drawn yet.
If you like coconut oil, great. If you don’t, great. Whether you choose to include it or not is up to you. Either way, your best bet is to include a variety of plant-based fats in your diet, and don’t look for any magic effects in a jar.