Wednesday, April 15, 2015

Coconut Oil Increases Cardiovascular Disease Risk and Possible Death Due to Heart Attacks and Stroke

If you do a Google search for “Coconut Oil Health Benefits” over four million results will pop up. Coconut oil has been made out to be a miracle cure for everything from heart disease to Alzheimer’s disease in our culture, but is it really true? What evidence do we have to support these claims?

The best way to evaluate any claim for any health product is to find peer-reviewed controlled interventional studies testing the use of that product on morbidity and mortality (i.e. disability and death) rates for the disease in question. Unfortunately, for coconut oil, there are no such studies. Without this data we’re left with testimonial stories of one miracle after another happening from those making coconut oil a popularized “health” product.

This is not to say that these individual miracle cases of people ‘reversing’ their Alzheimer’s disease or improving their heart health didn’t occur. It’s just to say that we should not put too much stock into anecdotal stories of any individual claim regardless of what product, drug, supplement, surgery, procedure, or device is being used to treat that person’s serious medical condition.

Let’s take a look at what evidence we do have on coconut oil.

Scientific and Medical Evidence for Coconut Oil

Alzheimer’s disease

There are no peer-reviewed controlled interventional studies observing morbidity and mortality for Alzheimer’s disease as of this date. (If you are aware of any such studies please provide a link to the referenced study in the comments below.)

The Alzheimer’s claim with coconut oil stems from a Florida physician who wrote a book about using ketones to cure Alzheimer’s disease. She supposedly treated her husband (who was diagnosed with Alzheimer’s disease) with coconut oil and claims that this led to the remarkable results of reversing her husband’s condition.

To read more about this coconut oil and Alzheimer’s disease story click here.

Cardiovascular Disease

There are no peer-reviewed controlled interventional studies observing morbidity and mortality for coconut oil in the treatment of cardiovascular disease as of this date. (If you are aware of any such studies please provide a link to the referenced study in the comments below.)

However, there are peer-reviewed controlled interventional studies on the addition of coconut oil supplementation to one’s diet and the resultant effect on a person’s blood markers associated with cardiovascular disease risk. These data indicate a potential increase in risk for heart disease. While this data is helpful, it still falls short of proving a direct cause/effect relationship between coconut oil and heart attacks/strokes/death rates. It does, however, provide us with a red flag as to the potential of these events occuring if one were to regularly consume coconut oil.

Study #1

In 1985, the American Journal of Clinical Nutrition published a study comparing the effect of beef fat, coconut oil, and safflower oil on plasma lipid levels in human test subjects.1 Investigators took nineteen healthy men in their mid-twenties consuming a typical Western-type diet, consisting of 35% total calories from fat, and substituted 60% of these fat calories with either beef fat, coconut oil, or safflower oil. Baseline and 5-week lipid panel levels were done for all test subjects. Results are below for the coconut oil group:

Average baseline lipid panel levels prior to coconut oil substitution
Total cholesterol – 158 mg/dl
HDL – 45 mg/dl
LDL – 96 mg/dl
Triglycerides – 80 mg/dl

Average lipid panel levels after 5 weeks of coconut oil substitution
Total cholesterol – 168 mg/dl
HDL – 46 mg/dl
LDL – 110 mg/dl
Triglycerides – 78 mg/dl

Heart attack and stroke risk can be largely predicted based on total and LDL cholesterol levels in people. William Roberts, MD (a world renown cardiac pathologist) states this in his article entitled Twenty Questions on Atherosclerosis – “The connection between cholesterol and atherosclerosis is strong … In societies where the serum total cholesterol is < 150 mg/dl, the frequency of symptomatic and fatal atherosclerosis is exceedingly uncommon; in contrast, in societies where the total cholesterol level is > 150 mg/dl, the frequency of symptomatic and fatal atherosclerosis increases as the level above 150 increases.”2

The test subjects in this study on coconut oil experienced worsening total and LDL cholesterol levels. As Dr. Roberts states, as cholesterol levels increase so does one’s risk of symptomatic and deadly heart disease.

Study #2

In 1996, a study was published evaluating the effect of psyllium fiber supplementation to diets of soybean and coconut oil.3 Test subjects underwent 7-day treatment periods and received either soybean oil (SO), soybean oil plus fiber (SO + PF), coconut oil (CO), or coconut oil plus fiber (CO + PF).

A total of 30% of total calories in the diet consisted of fat calories (20% from the test oils and 10% from the food). Investigators found that the “CO diet increased serum cholesterol, LDL, and apo B.”

apo B is a protein involved in the metabolism of lipids and is the main protein constituent of VLDL (very low-density lipoproteins) and LDL. Concentrations of apo B tend to mirror those of LDL, so the higher the level of apo B the greater the risk of heart disease.

In this study, all three cholesterol markers went up. This would signify an increase risk of cardiovascular disease.

Study #3

In 2001, an epidemiological study was performed to assess the role of nutrition in mortality rates between two groups of populations—inhabitants of Hong Kong and Singapore.4 The majority of both populations are ethnic Chinese so genetic variation would have played little, if any, role in study results.

[Note – Epidemiological studies are good for predicting a correlation between two factors in a study. For example, as helmet wearing increases in populations riding bikes, death due to bike accidents decreases in this same population. While this example falls short of proving a direct cause/effect relationship of helmets being the sole reason for a reduction in death rates, it is still a strong predictor of what might happen to any one individual who chooses to wear a helmet while riding a bike.]

Investigators in this study found that ischemic heart disease mortality was approximately three times higher in both men and women in Singapore versus Hong Kong. Multiple nutritional differences were found to be of possible explanation for this difference.

Investigators stated – “The ratio of animal fat to vegetable fat was higher in Singapore (2.24) than in Hong Kong (1.08). Singapore had higher serum concentrations of total cholesterol and low-density lipoprotein (LDL) cholesterol than Hong Kong.”

Investigators went on to say that there was “…a higher consumption of coconut and palm oil, mainly containing saturated fat, in Singapore.”

This study shows a clear link between animal food and oil consumption (specifically coconut and palm oils) and higher rates of dying from heart attacks.

Study #4

In 2001, the British Journal of Nutrition published a peer-reviewed controlled interventional study to evaluate the impact of reducing saturated fat or partially replacing it with unsaturated fat on blood cholesterol levels in their test subjects.5 Investigators reduced the amount of coconut fat over time in these subjects due to coconuts consisting mostly of saturated fat.

[Note – Coconut oil is 100% fat, approximately 90% of this fat is in the form of saturated fat. This is the reason why coconut oil is semi-solid at room temperature, unlike all other oils which are liquid at room temperature.]

The diet consisted of three phases listed below.

1) Two-week preliminary phase consisting of 31% of total calories from fat (17.8% of total calories from coconut fat)

2) Subjects then switched to an 8-week diet (Phase 1) consisting of 25% of total calories from fat (9.3% of total calories from coconut fat)

3) Subjects were then split up into two groups and put on a 52-week diet (Phase 2) as follows:
- Group A – 20% of total calories from fat (4.7% of total calories from coconut fat)
- Group B – 24% of total calories from fat (4.7% of total calories from coconut fat)

Phase 1 end results:
Average total cholesterol reduced by 7.7%
Average LDL cholesterol reduced by 10.8%

Phase 2 end results:
- Group A
Average total cholesterol reduced by additional 4.2%
Average LDL cholesterol reduced by additional 11%

- Group B
Average total cholesterol reduced by additional 4%
Average LDL cholesterol reduced by additional 16.2%

Again we see a significant reduction in harmful cholesterol levels when individuals reduce the amount of total and saturated fat in their diet and remove a good amount of coconut fat from their diet.

As pointed out by Dr. Roberts earlier, this can only bode well for these individuals as lower cholesterol levels lead to lower cardiovascular disease risk and less heart attacks and stroke.


Coconut oil is consumed by many people as a supplement to their overall diet. These individual’s intentions are well-meaning, but the results might not be. Unfortunately, there is no legitimate scientific evidence, in the form of peer-reviewed controlled interventional studies, to back up the health claims of consuming coconut oil.

By supplementing one’s diet with coconut oil, it only increases blood markers (lipid levels) that have been associated with higher rates of cardiovascular disease. You’re more likely to experience a heart attack or stroke by doing so, not less. It’s always better safe than sorry. Until definitive proof in the form of peer-reviewed controlled interventional studies comes forth supporting the health claims of coconut oil, it’s best to steer clear of this potentially harmful substance.

To learn more about oils in the diet please read my article, 3 Myths of Consuming“Healthy” Oils.

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by Dustin Rudolph, PharmD
Clinical Pharmacist

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Photo credit: HD Walls

1 Reiser R, Probstfield JL, Silvers A, et al. Plasma lipid and lipoprotein response of humans to beef fat, coconut oil and safflower oil. Am J Clin Nutr. 1985 Aug;42(2):190-7.
2 Roberts WC. Twenty questions on atherosclerosis. Proc (Baylor Univ Med Cent). 2000 Apr;13(2):139-43.
3 Ganji V, Kies CV. Psyllium husk fiber supplementation to the diets rich in soybean or coconut oil: hypercholesterolemic effect in healthy humans. Int J Food Sci Nutr. 1996 Mar;47(2):103-10.
4 Zhang J, Kesteloot H. Differences in all-cause, cardiovascular and cancer mortality between Honk Kong and Singapore: role of nutrition. Eur J Epidemiol. 2001;17(5)469-77.

5 Mendis S, Samarajeewa U, Thattil RO. Coconut fat and serum lipoproteins: effects of partial replacement with unsaturated fats. Brit J Nut. 2001;85:583-589.


  1. What a breath of fresh air to see references to and discussion of the actual evidence (and lack thereof). Thanks for this review - it's a great contribution to the discussion, to all who take the time to wade past the hype.

  2. Oh my, I have been eating coconut oil and a raw food diet for 15 years. I am in great health now. The "doctors" told me I would never completely heal candida or the leaky gut. They were so wrong. This is my experience. I have had blood work done and the results were good. So, hummm, I wonder.

    1. One can get away with a few harmful things when eating mostly raw plants. It would be an interesting experiment to cut out the coconut oil for a couple of months and have the blood tests run again, just to see the effects on what I assume is an already good cholesterol level.

  3. What kind of coconut oil are they using in these studies? From what I have heard, they were using refined types of coconut oil in these studies that were not organic. It seems like the coconut oil today would be different than the products they were using in 2001. I would be interested to get your opinion on this, and the role of saturated fat in the body that could be positive. Thanks!

    1. The type of coconut oil was not specified. However, whether organic or non-organic the macronutrient makeup and effect of coconut oil on the human cardiovascular system does not change. It's the total and saturated fat content that promotes coronary artery disease, not pesticides, herbicides, and insecticides. For anyone who has claimed that organic coconut oil is health-promoting the burden is on them to provide controlled interventional studies to prove their point.

  4. I agree with this, but what about coconut?

    1. Study number four listed above involved coconut fat. It didn't specify to my recollecting whether coconut fat meant the whole coconut or the coconut oil squeezed out of the plant. In general, anytime you process food from it's original source (like olive oil from olives or coconut oil from coconuts) it typically does not improve health and only poses health risks. However, I couldn't find any controlled, interventional studies specifying using the whole coconut. Maybe you have seen some?


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