At
a dinner party I recently hosted, a good friend of mine and I started talking
about coconut oil. Like me, he eschews all oils and other high-fat, highly
processed foods, believing that a diet consisting of 75-80% carbohydrate,
10-15% protein, and only 10% fat to be the ideal diet combination of macro
nutrients.
Basically,
my friend was arguing that coconut oil, which is 100% fat, has a large amount
of saturated fat and doesn’t even have the trace minerals and nutrients found
in olive oil and other plant-based oils. As such, he was wondering where people
got the idea that coconut oil was a “good” oil.
The Pros:
My friend
was right; coconut oil is devoid of even trace amounts of vitamins and minerals
(for those keeping score, I guess you can count that as a point for olive oil,
but honestly we are talking about such small amounts that its really
negligible). Rather, the reason so many people think coconut oil is a
beneficial oil is because of the fatty acids it contains- in particular,
medium-chain triglycerides (MCT), a type of saturated fat. The MCTs make
coconut oil unique because nearly all other oils (animal or plant-based) are
comprised of long-chain triglycerides (LCT). MCTs are broken down almost
immediately by enzymes in the saliva and gastric juices so that pancreatic
fat-digesting enzymes are not even required to complete the digestive process. In the digestive
system MCTs are broken down into individual fatty acids. Unlike other fatty
acids, these individual acids are absorbed directly from the intestines and
sent straight to the liver where they are, (for the most part) burned as fuel,
much like a carbohydrate. In this respect they act more like carbohydrates than
like fats.
Other
fats require pancreatic enzymes to break them into smaller units. They are then
absorbed into the intestinal wall and packaged into bundles of fat (lipid) and
protein called lipoproteins. These lipoproteins are carried by the lymphatic
system, bypassing the liver, and then dumped into the bloodstream, where they
are circulated throughout the body. As they circulate in the blood, their fatty
components are distributed to all the tissues of the body. The lipoproteins get
smaller and smaller, until there is little left of them. At this time they are
picked up by the liver, broken apart, and used to produce energy or, if needed,
repackaged into other lipoproteins and sent back into the bloodstream to be
distributed throughout the body. Because of the difference between the two
processes, coconut oil companies are able to market their product as an energy food
and even claim it doesn’t contribute to body fat the way other oils do.
The
fact that MCTs digest immediately to produce energy and stimulate metabolism
has led athletes to use them as a means to enhance exercise performance. Some studies
indicate this may be true. In one study, for example, investigators tested the
physical endurance of mice that were given MCTs in their daily diet against
those that weren't. The study extended over a six-week period. The mice were
subjected to a swimming endurance test every other day. They were placed in a
pool of water with a constant current. The total swimming time until exhaustion
was measured. While at first there was little difference between the groups of
mice, those fed MCTs quickly began to out-perform the others and continued to
improve throughout the testing period. Tests such as this demonstrated that MCTs
had the ability to enhance endurance and exercise performance, at least in
mice.
In
another study, this one using humans, cyclists pedaled for three hours. During
the last hour they were each given a beverage to drink. Those who received
beverages containing MCTs reportedly outperformed the others.
The
claim is that MCTs provide an energy boost while also boosting the rate of the
metabolism. When
the metabolism is increased, cells function at a higher rate of efficiency,
helping to heal injuries quicker, and replaced old cells faster. Amazingly,
because of this, coconut oil companies (a product that is 100% fat) claims
their product can actually help people lose weight. Even recognized health
experts repeat this claim, as Dr. Oz told his followers, "The first of the
health benefits of coconuts—the one you're going to care about a lot—is weight
loss."
The Cons:
Others
argue that instead of focusing in on the “trees” or the MCTs that are found in
coconut oil, we need to step back and view the “forest” or the fact that
coconut oil is one of the highest sources of saturated fat. Nearly 92 percent
of its fat is saturated. For comparison, olive and soybean oils are about
15 percent saturated, while beef fat is about 50 percent saturated and butter
is 63 percent saturated. According to the senior nutrionist at The Center for
Science in the Public Interest, David Schardt, only Palm Kernel oil has more
saturated fat. The consumption of saturated fats can raise cholesterol and
increase the risk of heart disease as well as stroke.
David
Schardt also tackles the claim that coconut oil will help slim peoples waists.
Apparently there has only been one real research study testing if coconut oil
could help people lose weight. It didn’t. At the end of the study, both the
control and the test groups lost the same amount of weight during the course of
four days while cutting their calories and adding exercise to their daily
regimen. This is pretty skimpy evidence.
Instead,
the claims about losing weight come from a group of small studies where
specifically formulated 100% MCT oil was consumed (coconut oil is less than
60%). Even these findings were insignificant.
The
research on coconut oil and cholesterol is similarly scarce, but what has been
done shows that coconut oil raises HDL cholesterol (good cholesterol) but
raises LDL cholesterol (bad cholesterol) as well, which can increase the
chances of cardiovascular disease. As Dr. Esselstyne, of the Cleveland Clinic
notes, HDL cholesterol only rises in the presence of LDL cholesterol and a
lower overall cholesterol is always preferred.
To
further dismiss the marketing advertisements of coconut oil, nutritionist Jeff
Novick suggests examining the nutrient density of coconut oil. The nutrient
density of any food is defined
as a ratio of nutrient content (in grams) to the total energy content (in
calories).
After running the numbers, Novick notes that 100 calories of coconut oil
contains almost no protein,
vitamins, minerals, or fiber- adding almost no nutritional value while only 4
teaspoons surpasses the American Heart Association’s recommended daily intake
of saturated fat. Coconut oil is high in calories and fat while giving no
nutrients in return. As such, Novick concludes that coconut oil is the opposite
of a nutrient dense food. Finally, when compared to the nutrient density of
sugar, coconut oil actually fared worse.
In addition, Jeff Novick adds that
another recent study looked at the effects of even just one high fat meal on HDL, inflammation, and blood flow. Subjects
were fed a meal high in calories from coconut oil and the effects were
evaluated at 3 and 6 hours after the meal. The meal containing coconut oil
impaired the anti-inflammatory action of HDL at both 3 and 6 hours. In
addition, blood flow was significantly reduced 3 hours after the meal
containing coconut oil and remained slightly reduced at 6 hours. If these
studies are correct, (and there is no reason not to trust them,) consuming
coconut oil would actually hinder athletic performance.
He also
adds that while MCTs do have some benefits, only a small portion of the fats in
coconuts are in the form of MCTs but adds that many times, the MCTs are
actually removed from the coconut to be used in the medical or cosmetic
industry before being turned into coconut oil.
While
ultimately the decision to consume coconut oil remains a completely personal choice, it seems
like optimal health can only be achieved with minimal to no coconut oil. The
small benefits that could possibly be gained from consuming MCTs do not seem worth
the long-term health risks.
So
perhaps a good New Year resolution is to forget the hyperbole of the coconut oil marketing, and kick coconut
oil to the curb.
Hope
you all had a wonderful holiday.
Further
Reading:
Kiyasu
G.Y., et al. 1952. “The Portal Transport of Absorbed Fatty Acids.” Journal of Biological Chemistry 199:415.
Fushiki,
T. and Matsumoto, K. 1995, “Swimming Endurance Capacity of Mice is Increased by
Chronic Consumption of Medium-Chain Triglycerides” Journal of Nutrition 125:531.
Applegate,
L. 1996. Nutrition. Runner's World
31:26.
Brazier,
Brendan, Thrive: The Vegan Nutrition
Guide to Optimal Performance in Sports and Life. Da Capo Life Books, New
York: 2008.
J Am Coll Cardiol, “Consumption of
Saturated Fat Impairs the Anti-Inflammatory Properties of High-Density
Lipoproteins and Endothelial Function,” 2006; 48:715-720.
Schardt, D., “Coconut Oil”: Lose Weight?
Cure Alzheimer’s? Clog your Arteries?” Center for Science in the Public
Interest, Nutrition Action June 2012.
Novick, J. “Marketing Junk Food: Don’t go
Cuckoo Over Coconut Oil.” Newsletter, 4/10/2008.