Coconut Oil: Separating Fact From Fiction

Have you heard about the awesome health benefits of coconut oil? If you haven’t, you may want to consider leaving that rock you’re currently living under. The coconut oil craze began around 2013 and has been going strong since. I thought the hype would have faded out by now, but I continue to see it promoted as a cure-all for numerous health ailments. Before we jump on the coconut oil bandwagon, let’s take a step back and look at the evidence behind some common health claims surrounding coconut oil.

Coconut Oil for Cosmetic Health

Coconut oil is marketed as an all-natural moisturizer capable of rejuvenating your hair and skin. I don’t know much about beauty products (and I don’t have any hair), but I think we’re on to something here. Most brand-name cosmetics are littered with harsh chemicals that muck with our hormones, negatively impact our reproductive health, and may even cause cancer. If coconut oil can replace any of these chemical-laden products, I’m all for it. My wife has used it as a skin moisturizer, but stopped because our dog would follow her around trying to lick it off her arms and legs.

Another popular use for coconut oil is “oil pulling”. This is where you take a tablespoon of edible oil and swish or “pull” the oil through your teeth and around your mouth for a few minutes. Oil pulling is an ancient, traditional folk remedy that has been used for centuries in India and Southern Asia as a holistic Ayurvedic practice.

Is there any evidence that oil pulling improves oral health? Some, but it’s limited. Studies have shown that oil pulling can help prevent bad breath, reduce dental plaque, improve gum health, and reduce the number of oral bacteria that contribute to tooth decay (1-3). These studies were conducted over short durations and only had a small number of participants. They also used sesame oil, not coconut oil. Another study showed that oil pulling did not reduce oral bacteria that contribute to tooth decay (4). Based on this data, it’s probably safe to say that oil pulling may have some benefits, but the evidence is weak and the studies didn’t specifically use coconut oil. There doesn’t appear to be any major negative side effects to oil pulling though, so if you want to give it a try, go ahead.

Using coconut oil on our hair and skin, or swishing it around your mouth, is one thing, but what about eating it? Should it be considered a “superfood”, or just snake oil?

Coconut Oil and Cardiovascular Health

Like all oils, coconut oil is pure fat. What makes coconut oil unique, however, is that it’s roughly 90% saturated fat, compared to say olive oil, which is about 15% saturated fat. Despite recent headlines, saturated fat does raise LDL (bad) cholesterol and its consumption is associated with an increased risk of heart disease (5). But not all saturated fats are created equal. For example, the saturated fat in beef is a lot different than saturated fat in coconut oil. Based on these differences, people claim that the saturated fat in coconut oil does not have a negative impact on our cardiovascular health.

The idea that saturated fat from coconut oil is “heart healthy” can be traced back to a handful of studies. The most popular one was a 1981 study that looked at the dietary habits of two Polynesian islands—Pukapuka and Tokelau—where coconut, in various forms, made up 34 and 63 percent of their total caloric intake, respectively. As you can imagine, their saturated fat intake was through the (thatched sugar cane leaf) roof! Yet researchers found that “Vascular disease is uncommon in both populations and there is no evidence of the high saturated fat intake having a harmful effect in these populations”.

It’s important to note that their overall diet was the complete opposite of what most Americans eat. Both island populations were eating a predominantly plant-based diet with breadfruit, taro, and rice as their main staples. Meat was only consumed on special occasions and dairy products were not a part of their diet. They also consumed very little refined flour, added sugar, and processed foods. One cannot extrapolate the health implications of coconut oil from these island populations and apply them to the typical American eating the typical American diet.

Beyond this population-based study, there are numerous interventional studies that have looked at coconut oil and cardiovascular risk factors, specifically, its effects on blood cholesterol levels. A 2016 review of such studies, reported that overall, consuming coconut oil raises total, LDL, and HDL cholesterol. It also found that removing coconut oil from one’s diet leads to reductions of total and LDL cholesterol (7). In other words, adding coconut oil to your diet increases blood cholesterol levels (which we don’t want) and removing it reduces blood cholesterol levels (which we do want). Some people point to the increase in HDL (so-called good) cholesterol, as reason to call coconut oil “heart healthy”, but more and more evidence suggests that the role HDL cholesterol plays in cardiovascular disease is minor, and that reducing LDL (the bad) cholesterol should be the main focus. Another 2016 review on the subject concluded that “Coconut oil generally raised total and LDL-cholesterol to a greater extent than unsaturated plant oils, but to a lesser extent than butter” (8). In terms of cardiovascular health, this is a great way to view coconut oil. It’s worse than other plant oils (olive, canola, etc.), but it’s not as bad as butter.

Coconut Oil and Metabolism/Weight Loss

Those who promote consuming coconut oil because they believe it can boost metabolism and help people lose unwanted pounds, point to the medium-chain triglycerides (MCT), a type of fatty acid found in coconut oil, as their supporting evidence. MCT are absorbed and metabolized differently compared to other fats, and there is some evidence to suggest that these differences may allow them to be used more readily for energy, as opposed to being stored as body fat (9). In addition, there is some evidence to suggest that MCT may be more satiating compared to other fats, but it is very limited. Plus, these studies used MCT oil, not coconut oil. Coconut oil is only about 63% MCT. What we need are studies looking specifically at coconut oil and weight loss.

Ta-dah! There are a few studies that look specifically at coconut oil and weight loss. These studies show that using coconut oil, compared to a control oil, may lead to a small reduction in waist circumference, but not weight loss (10-12). These studies were small and of poor quality, so the results should be taken with a grain of salt. Until more studies are done, the current evidence suggests that adding coconut oil to your diet may lead to a (minor) reduction in waist circumference, but will not result in weight loss. There is also no reported evidence that coconut oil increases metabolic rate in humans (7).

Coconut Oil and Brain Health and Alzheimer’s Disease

Coconut oil is often touted as being “good for the brain” and many claim that it can help prevent or treat Alzheimer’s disease. Yet the evidence to support these claims is severely lacking. Some studies have looked at MCT oil or a ketogenic diet (high fat, low protein, low carb) on cognition, but no human studies have directly looked at coconut oil and brain health or its role in Alzheimer’s disease (7). Until these studies are done, there is insufficient evidence to support any claims regarding coconut oil and brain health.

Summary

Coconut oil can be used as an all-natural hair and body moisturizer. Swishing it around in your mouth may improve oral health, but it’s no substitute for brushing. Neither of these cosmetic uses are likely to cause any harm, so give them a try if you want. The same cannot be said about coconut oil in our diet. The cumulative data suggests that eating coconut oil raises total and LDL cholesterol, neither of which we want. Given this, consumption of coconut oil should be limited in healthy people and totally avoided in people who have, or are at risk of developing, cardiovascular disease. The current evidence suggests that coconut oil does not lead to weight loss, and there is insufficient data to make any claims regarding its role in Alzheimer’s disease. Coconut oil is just another example of the mainstream media getting ahold of something and blowing it out of proportion. No hard feelings coconut oil, but you’re not as awesome as people think you are. Sorry.

Personal Use:

I have a jar of extra virgin coconut oil in my cupboard. It’s been there for years. I use it occasionally when baking (remember, it’s healthier than butter), or when making an Indian or Thai curry, but that’s about it. My wife has used it as a skin moisturizer, or as our dog calls it, a tasty snack.

References:

1. Effect of oil pulling on Streptococcus mutans count in plaque and saliva using Dentocult SM Strip mutans test: a randomized, controlled, triple-blind study.
2. Effect of oil pulling on plaque induced gingivitis: a randomized, controlled, triple-blind study.
3. Effect of oil pulling on halitosis and microorganisms causing halitosis: a randomized controlled pilot trial.
4. Comparative Evaluation of the Effects of Fluoride Mouthrinse, Herbal Mouthrinse and Oil Pulling on the Caries Activity and Streptococcus mutans Count using Oratest and Dentocult SM Strip Mutans Kit.
5. Intake of individual saturated fatty acids and risk of coronary heart disease in US men and women: two prospective longitudinal cohort studies
6. Cholesterol, coconuts, and diet on Polynesian atolls: a natural experiment: the Pukapuka and Tokelau island studies.
7. Coconut oil – a nutty idea?
8. Coconut oil consumption and cardiovascular risk factors in humans
9. Physiological Effects of Medium-Chain Triglycerides: Potential Agents in the Prevention of Obesity
10. An open-label pilot study to assess the efficacy and safety of virgin coconut oil in reducing visceral adiposity.
11. Effects of dietary coconut oil on the biochemical and anthropometric profiles of women presenting abdominal obesity.
12. A COCONUT EXTRA VIRGIN OIL-RICH DIET INCREASES HDL CHOLESTEROL AND DECREASES WAIST CIRCUMFERENCE AND BODY MASS IN CORONARY ARTERY DISEASE PATIENTS.