In last week's article “Four New, Cutting-Edge Ways To Easily Shift Your Body Into Fat-Burning Mode & Ketosis“, I finished with a somewhat mysterious word of caution to those who consume oodles of coconut oil (or MCT oil, for that matter).
In today's article, myself and my friend Alyssa Siefert, PhD (a Biomedical Engineering Instructor/Researcher at Yale) are going to tell you about the dark side of coconut oil, and reveal a cautionary, scientifically accurate tale for any coconut oil extremists who insist on adding oodles of coconut oil to every smoothie and spoonful after spoonsful of MCT oil to every cup of coffee.
So go ahead, slowly step away from the giant vat of coconutty goodness, and open your mind to the possibility that, in the same way that too much protein could reduce lifespan and too few carbohydrates can cause joint and gut damage, too much coconut oil and MCT could also be a bit rough on your body…especially if you fall into the specific categories we discuss in this article.
If you've recently looked into topics like ketosis, fat burning efficiency, low carb diets, or even candida cleansing, you've no doubt heard of the myriad of benefits derived from coconut oil. Because it is rich in the medium- and long-chain fatty acids (MCFAs and LCFAs) you're about to discover, coconut oil has too many compelling medicinal, metabolic, and cosmetic uses to list here.
And let's not beat around the bush: you'll find extra virgin coconut oil, full fat, non-BPA coconut milk, MCT oil and other similar fats recommended quite frequently here at BenGreenfieldFitness.com
However, the recent paper “Dietary Fatty Acids Directly Impact Central Nervous System Autoimmunity via the Small Intestine” shed light on the potential downside of medium- and long-chain fatty acids (MCFAs and LCFAs).
This well-designed, high-impact scientific paper showed that lauric acid (LA), which usually makes up 50% or more of coconut oil, tips the balance of T-cells (immune cells that actively participate in the immune response) towards the production of inflammation, and also, in mouse models, exacerbates multiple sclerosis (MS), in which your immune system attacks the protective sheath (myelin) that covers nerve fibers and causes communication problems between your brain and the rest of your body.
So should people with intestinal inflammation or risk of MS go against the popular opinion of the internets and the majority of new diet books out there and instead limit their consumption of coconut and MCT oil?Can too much coconut or MCT cause inflammatory or immune issues in your body?
Can too much coconut or MCT oil cause inflammatory or immune issues in your body?
Let's make some logical, data-driven conclusions, shall we?
First of all, what are MCFAs, LCFAs, MCT, PUFAs, MUFAs, and all these other confusing alphabet letter soup phrases?
Fatty Acids (FAs) are simply molecules consisting of long hydrocarbon chains capped with a carboxylic acid (COOH). This carboxylic acid is where “acid” part of fatty acid comes from. Fatty acids are termed “saturated” if there are hydrogen atoms at every possible position on the carbon chain, and “unsaturated” if there are open positions for hydrogens on carbons that are instead filled by a double bond between the carbon atoms.
Here's a pretty picture to demonstrate:
FAs that only have one double bond are called mono-unsaturated fatty acids (MUFAs), while FAs with multiple double bonds are polyunsaturated FA (PUFAs). Fats are formed by chains of fatty acids connected together with glycerol, and are classified as monoglycerides (one FA per glycerol), diglycerides (two FA per glycerol), or triglycerides (you guessed it – three FA per glycerol). If this is getting too nerdy to remember, just think that saturated fats are solid at room temperature and unsaturated fats are liquid at room temp and often used as cooking oils.
Fats, like those you would consume from foods, are formed by chains of these fatty acids that have been connected together with glycerol, and these fats can be classified as monoglycerides (one FA per glycerol), diglycerides (two FA per glycerol), or triglycerides (you guessed it – three FA per glycerol).
If this is getting too nerdy to understand, just remember: saturated fats are solid at room temperature (like coconut oil) and unsaturated fats are liquid at room temp (like extra virgin olive oil).
Anyhoo…let's get to know these FAs even better…
…Short-Chain Fatty Acids (SCFAs) have one to six carbon atoms, including acetic acid (C2), propionic acid (C3) and butyric acid (C6). SCFAs are made by the fermentation of dietary fiber such as vegetables by your intestinal bacteria (AKA your microbiota) and these SCFAs exhibit numerous health benefits, especially for preventing metabolic disorders by turning white adipose tissue into brown adipose tissue and by regulating blood sugar. SCFA treatments have also been shown to ameliorate mouse models of intestinal bowel disease (IBD) and allergic asthma.
Then we have FAs with longer chains of carbon atoms. The famous MCT oil is composed of Medium Chain Triglycerides that have FA chains ranging from 6-12 Carbons, including caproic acid (C6), caprylic acid (C8), capric acid (C10), and lauric acid (C12) – though, as you learned about in last week's article about how to get into ketosis, it is hotly debated among nerds whether lauric acid is considered a MCT or LCT.
And yes, FAs get even longer. LCFAs have 12 or more carbon atoms and include eicosapentaenoic acid (EPA) (20 Carbons), docosahexaenoic acid (DHA) (22 Carbons), and, depending on whom you ask, lauric acid (12 Carbons).
OK, enough with the science lesson – when it comes to stuffing or not stuffing your face with coconut oil, why does this stuff even matter?
To answer this question, let's get back to that recent study on coconut oil mentioned earlier.
While numerous internet articles on many popular diet and nutrition websites make a claim that over 1500 peer-reviewed scientific studies confirm that coconut oil is healthy, a quick Pubmed search shows that although there are that many studies relevant to coconut oil, many of them are not actually saying that coconut oil is a panacea.
Take a look at the screenshot below to judge for yourself.
Sure, there is indeed a great deal of high-quality scientific research showing that coconut oil has many health benefits, and even health benefits beyond the ones you've probably heard about a million times from various health gurus.
For example, did you know that coconut oil can mitigate the damaging effects of antibiotics? In this study, Nigerian researchers gave rats a broad-spectrum antibiotic (Trimethoprim-sulfamethoxazole), and produced significant increases in liver toxicity markers like serum total bilirubin, lactate dehydrogenase, and alkaline phosphatase. But supplementing these antibiotics with virgin coconut oil protected against this liver toxicity (here are a few other creative ways to limit the damage from antibiotics).
That said, the recent research findings mentioned earlier suggest that coconut oil is not healthy in all situations.
In the October 2015 issue of Immunity, a leading primary research immunology journal, the effects of FAs were meticulously investigated in a report entitled “Dietary Fatty Acids Directly Impact Central Nervous System Autoimmunity via the Small Intestine”. Download it here if you'd like.
In this study, researchers first added FAs ranging from C4 to C12 (from butyric acid to lauric acid) to naïve mouse T cells, showing that as the length of hydrocarbon backbone increased, the number of T cells that differentiated into Th17 cells increased in a strikingly linear fashion:
So what are Th17 cells, and why should we care?
Imbalanced T cell subsets drive numerous autoimmune diseases, and an abundance Th17 cells (called Th17-skewed immune system) can result in inflammatory autoimmune disease, including intestinal bowel disorder (IBD) and multiple sclerosis (MS).
See, Th17 cells are meant to attack parasites and pathogenic bacteria, but having too many of them in your body can increase the chances of their attacking your own tissues, such as myelin sheaths in the case of MS. But while Th17 cells promote inflammation, they can be balanced by anti-inflammatory regulatory T cells (Tregs), and it is the ratio of pro- and anti-inflammatory T cells, not the absolute number of each cell type, that is predictive of health and disease.
Therefore, researchers next quantified the effects of hydrocarbon chain length on Treg differentiation, finding that shorter chain FAs induced Tregs:
To determine if the Th17-skewing effects of LA were relevant to autoimmune diseases, mice with the mouse-version of MS (called EAE) were fed a diet of 30.9% fat with 13.5% of it LA (compared to control diet of 4.2% fat).
To relate this dietary regime to humans, for a person eating 2500 calories a day, that’s 750 calories from fat, and 101 calories from LA. Siince coconut oil is 120 calories per tablespoon, half of which come from LA, this translates to about 2 TB of coconut oil per day – a pretty reasonable dose. So since the dosing in this paper checks out, you can regard its results as likely relevant to your life (as opposed to studies that give crazy, otherworldly high doses of tested compounds).
Anyways, so back to this study. Mice eating higher amounts of LA exhibited Th17-skewing in the intestines, worsened MS symptoms, and changes in the microbiome (reduction in Prevotellaceae and S24-7 of the bacteria Bacteroidetes phylum). Disease worsening was actually worsened by this microbiota shift, as repeating this study with germ-free mice (that have no intestinal microbiota) did not result in Th17-skewing.
To be clear, these results show that high amounts of coconut oil can create rampant inflammation, nerve damage and worsen an autoimmune disease.
But wait, there's good news.
Remarkably, feeding mice the SCFA proprionic acid (C3) both prevented the onset and alleviated symptoms of MS. The overall conclusion of this study is that through the intestinal microbiota, LCFA can induce pro-inflammatory T cells, and SCFA ca induce anti-inflammatory, regulatory T cells.
Therefore, SCFA can mitigate the harmful effects of LCFA.
In other words, if you consume SCFA along with your coconut and MCT oil based LCFAs, you mitigate the damage.
And where do you get SCFAs in quite generous amounts?
You guess it: vegetables.
A high-fat diet? Thumbs mostly down.
A high-fat diet mixed with a high intake of nutrient-rich, SCFA-inducing plants? Thumbs up.
Again and again, we see that health is achieved through balance (and at the end of this article, we'll give you a link to a podcast in which I discuss the details of a high-fat, plant-based diet).
But wait. The tale of the dark side of coconut oil is not quite finished.
Another recent study highlights another potential risk of coconut oil. Researchers investigating the effects of soybean oil, alone and in conjunction with fructose (which has increased significantly in American diets), fed mice 40% of their daily calories from fat, either from coconut oil alone or a 50/50 mix of coconut and soybean oils.
Compared to 40% of calories from coconut oil alone, mice consuming soybean oil had increased obesity, insulin resistance, diabetes, and fatty livers, showing that the adverse effects were from the chemical nature of soybean oil, not the macronutrient breakdown.
So that’s a win for coconut oil, right?
Interestingly, in the same study, mice fed all high-fat diets tested (coconut oil, coconut oil + soybean oil, with and without fructose supplementation), exhibited significantly reduced lengths of both small and large intestines. Researchers reasoned that this intestinal shortening, which has broad implications for microbial colonization and nutrient absorption, is likely due to reduced fiber intake, since 40% of calories were fat.
OK, these findings are kind of scary – so now should I stop eating coconut oil?
Back it up.
Coconut oil + SFCAs = good.
Coconut oil + fiber = good.
Coconut oil dumped into a cup of coffee, followed with a lone carrot beside your lunch and perhaps a scant serving of roasted vegetables with dinner? Not so good.
To put this in perspective, as you can read about here, Ben eats about 15-20+ servings of plants per day. And because of this, he gets away with a decent amount of coconut milk, coconut oil and MCT oil intake. All the SFCAs and fiber help balance out the potentially damaging effects of the fat, while still allowing him to get all the benefits of the fat.
Coconut oil, with around 90% of calories from saturated fat, 65% of which are MCTs, has been lauded as an ideal fat for cooking, ketosis, and prevention of metabolic and cardiovascular diseases. So we're not saying coconut oil is unhealthy – just that it may be overhyped, and is too often recommended without simultaneous recommendations to eat your friggin' vegetables.
As you can see, Ben likes to eat plants.
Before finishing up with a couple more practical recommendations and resources for you, here are a few caveats.
While it is tempting to accept as fact all conclusions drawn from studies published in peer-reviewed journals, as an academic, you need to realize that not all peer-reviewed journals are created equal. Scientific and medical journals are ranked by impact factor, with higher impact factors usually correlating with more rigorous, unbiased review processes of submitted data. Therefore, researchers regard conclusions from publications in high impact-factor journals, like Nature or New England Journal of Medicine, with greater levels of confidence than publications from low impact journals, which can suffer from shady and nepotistic publishing practices.
In addition, data and conclusions are only as valid and applicable as the experimental and statistical methods used. Often, gold-standard findings are found in meta-analyses, in which unbiased researchers (like epidemiologists or statisticians) re-analyze massive data sets from multiple studies. Still, when considering whether or not to apply findings from health-related studies to your own life, think about how robust the methods used are (did the researchers study 10 people or 10 thousand?), the dosing regime, and how similar you are to the experimental subjects.
Why are we telling you this?
Because the studies you just learned about are indeed valid, applicable and gold-standard studies. Not N=1 experimentation or tiny or sponsored by the anti-coconut-oil industry. So they're important for you to know about.
But wait…weren't these studies done in mice guts? Last I checked, we didn't have tiny tails and cute whiskers…
The recent scientific paper “How informative is the mouse for human gut microbiota research?” helps elucidate this for us (the whole paper is actually quite fascinating and worth a read, especially if you don't have a social life):
“…their advantages are numerous and, furthermore, the amount of research and knowledge on mouse gastroenterology, genetics and immunology far surpasses any other model. Murine mouse models provide a range of customizable genotypes and phenotypes far superior to any other model organism. They have thus played a very important role in the emerging gut microbiota research field. Owing to their widespread use in biomedical research, these models are complemented with extensive knowledge on genetic background and deep phenotypic and functional characterization. Moreover, with well-set-up standardized mouse house facilities throughout labs in the world, conducting experiments on mouse models, even germ-free ones, can be more easily achieved than with other models.”
Finally, as pointed out at the WholeHealthSource website, “Butyrate Suppresses Inflammation in the Gut and Other Tissues”:
“There are two main ways to get butyrate and other short-chain fatty acids. The first is to eat fiber and let your intestinal bacteria do the rest. Whole plant foods such as sweet potatoes, properly prepared whole grains, beans, vegetables, fruit and nuts are good sources of fiber. Refined foods such as white flour, white rice and sugar are very low in fiber. Clinical trials have shown that increasing dietary fiber increases butyrate production, and decreasing fiber decreases it.
Butyrate also occurs in significant amounts in food. What foods contain butyrate? Hmm, I wonder where the name BUTYR-ate came from? Butter perhaps?”
So yes, although you can overdo butter just like you can overdo coconut and MCT oil, if you are indeed consuming lots of LCFAs and MCTs, consume a bit of butter too. Thank you, Dave Asprey and Bulletproof Coffee, for pointing that out quite extensively.
Anyways, back to those practical recommendations.
Dr. Alyssa Siefert has a tablespoon of unrefined (virgin) coconut oil in her morning coffee, but she is mindful not to exceed a few tablespoons a day unless she is matching this increased LCFA consumption with fiber from whole plant foods, as fiber intake directly correlates with SCFA production in a healthy gut. She also reads labels to ensure she's consuming organic unrefined (virgin) coconut oil that hasn't been hydrogenated.
And, as mentioned earlier, Ben accompanies his 70-90% fat based diet with oodles and oodles of plant matter at each meal, and doesn't count any carbohydrates he gets from sources like kale, spinach, tomatoes, etc. as part of his total daily carbohydrate intake.
The adverse effects of a high-fat diet may not result from what you're putting in your body, but what you're taking out (usually fiber) to allow increased intake of fats like coconut oil.
If you do happen to be a person whose baseline immunity tends toward inflammatory (for instance, a history of autoimmunity or skin conditions), then you should be especially be cautious about the amount of LCFA, MCT's and coconut oil you consume, but we still consider coconut oil a much healthier replacement for the unsaturated fats like canola oil (that used to be touted as heart-healthy, especially for cooking).
So don't fall into nutrition extremism. Including some coconut and MCT oil in your life is great, more is not necessarily better, especially if you're not going out of your way to eat plants, which can be admittedly more time-consuming than spooning fat into a cup of coffee or tea.
If you enjoyed this article and want more balanced, accessible science updates on your newsfeed, then check out Dr. Alyssa Siefert at The Sociable Scientist on Facebook! And leave your questions, comments and feedback below. And eat your vegetables.