Coconut Oil: Hero Or Zero? | PaleoPharm

Aug 11, 2012

Misinformation regarding coconut oil abounds on blogs and websites. A large number of healthcare professionals believe this tropical oil will promote atherosclerosis and lead to heart attacks.

I found one dietitian who has taken it upon himself to post warnings on multiple websites against using coconut oil because he claims it contains only a negligible amount (10 percent) of beneficial medium-chain triglycerides (MCT)?his first error?and because he believes coconut oil will adversely affect blood lipid profiles and consequently promote heart disease?a position that is not supported by a large number of preclinical, clinical, and population studies. He unabashedly announces that his statements and opinions represent ?the facts.?

This Ozymandius-level arrogance caught my attention because I believe I should be the only bloviating nutritionist on the net permitted to make such an audacious pronouncement! I hope the Internet Police agree.

I?ve analyzed the scientific validity of this dietitian?s questionable statements regarding coconut oil dangers because they reflect the beliefs and confirmation bias of others in the health and fitness fields at a time when millions of people are discovering the delicious taste and the weight-loss and health benefits of the oil. Without further ado, here is my presentation of ?the facts? about coconut oil.

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Coconut Oil Confusion

Scientists classify triglycerides according to the carbon chain length of the individual saturated fatty acids they contain. Triglycerides with saturated fatty acids of 6?12 carbons in length are classified as MCT, or ?medium-chain triglycerides,? as any biochemistry 101 student knows (see here, here, and here).

Data from a number of research studies suggest that MCT found in coconut oil account for its unique health and weight-loss benefits. For those keeping score, the MCT fatty acid profile of non-hydrogenated coconut oil is composed of 1.5% caproic acid (C6), 5-11% caprylic acid (C8), 4-9% capric acid (C10), and 40-50% lauric acid (C12). Published evidence suggests that the body does not convert MCT to cholesterol and preferentially burns MCT for energy instead of storing them in adipose tissue.

These numbers reveal that coconut oil is actually composed of between 58-70 percent MCT (average: 65 percent) and not 10 percent as the misguided dietitian asserts. Coconut is thus a significant dietary source of MCT.

For the sake of completeness, I confirmed these numbers with the following authoritative sources:

Against facts, there are no arguments?unless the facts have been twisted into fiction.

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Flawed Studies Lead To Myth and Misinformation

One should not make sweeping generalizations about coconut oil?s atherogenic potential based on its saturated fatty acid profile because most studies that have examined the ability of saturated fats to unfavorably modify the LDL:HDL cholesterol ratio have used saturated fatty acids that were mainly derived from animal sources. These sources do not possess the unique and beneficial MCT profile of coconut oil and therefore any suspected health risks of coconut oil cannot be determined from such studies. Moreover,? most coconut studies conducted on dogs, gerbils, mice, monkeys, rabbits, and rats were flawed because they used hydrogenated coconut oil (hydrogenated fats have been shown to create unhealthy blood lipid profiles) and because the diets were low in or devoid of linoleic acid (18:2 n16), which led to essential fatty acid deficiency (see: Kintanar, Q. L. Is coconut oil hypercholesterolemic and atherogenic? A focused review of the literature. Trans Fat Academy Science and Technology (Phil) 1988;10:371-414).

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Coconut Oil: Evidence-Based Research

Although coconut oil has been shown to exert antibacterial, antiviral, and antifungal activity, including activity against all lipid-coated (gram negative) bacteria, nutritionists and dieters are more interested in coconut oil?s reported ability to help people lose body fat and reduce the risk of heart disease.

Are such reports founded in fact or fiction?

As I established at the beginning of this post, coconut oil contains about 65 percent MCT. The liver rapidly metabolizes MCT for energy and therefore, MCT do not participate in the biosynthesis and transport of cholesterol. Under normal physiological conditions, coconut oil MCT are not deposited in adipose tissue and when coconut oil replaces other fats in the diet, it does not lead to obesity. Numerous preclinical, clinical, and population studies that have investigated a possible link between coconut oil use and obesity and cardiovascular disease risk factors have thus far shown that concerns about such links remain speculative and unproven:

A randomized, double-blind study in 40 women found that coconut oil use resulted in reductions in abdominal obesity and waist circumference when it replaced other fats in the diet. Such anthropomorphic changes have been confirmed and are widely acknowledged as favorable modifications to cardiovascular risk profiles.

Investigators of a study of 32 patients diagnosed with coronary heart disease (CHD) and 16 age and sex matched healthy controls (both groups had similar intakes of coconut, coconut oil, total fat, saturated fat, and cholesterol) found ?no specific role for coconut or coconut oil in the causation of CHD.?

A study of 1,839 Filipino women (age 35-69 years) found that dietary coconut oil intake was positively associated with HDL-cholesterol levels. Investigators concluded that, ?Coconut oil consumption was not significantly associated with low density lipoprotein cholesterol or triglyceride values,? two suspected risk factors for cardiovascular disease.

A controlled crossover study of female college students compared the effect of a high saturated fat (coconut oil) diet on postprandial t-PA and Lp(a) with a low-saturated fat diet without a change in the polyunsaturated/saturated fatty acid ratio. Investigators found that the high-saturated fat coconut oil?based diet lowered postprandial t-PA antigen concentration, thus favorably modulating the fibrinolytic system, and lowered the Lp(a) concentration, thereby reducing cardiovascular disease risk, compared with a high-unsaturated fat diet.

Researchers who reviewed studies on the effects of feeding MCT-rich coconut oil to humans concluded that ?MCT increase energy expenditure, may result in faster satiety, and facilitate weight control when included in the diet as a replacement for fats containing LCT [long-chain triglyderides].?

A preclinical study found that coconut oil added to the diet of rabbits at up to 30 percent of daily energy requirements did not cause hypercholesterolemia or oxidative stress.

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Real Life Examples: Population Studies

Results of preclinical and clinical studies are informative, but what is the observed cardiovascular disease risk and incidence of heart disease in free-living populations that consume large amounts of coconut oil?

One study of two South Sea Island populations?the Pukapuka and Tokelau Islanders?found no evidence of dangerously elevated blood cholesterol levels resulting from a coconut oil-rich diet. The Pukapukans, who get 35 percent of their daily calories as fat?75 percent from coconut oil?have total cholesterol levels averaging 170 mg/dL for men and 176 mg/dL for women. The Tokelauans, who consume 50 percent of their daily calories from fat?90 percent from coconut oil?had average cholesterol levels of 208 mg/dL for men, 216 mg/dL for women.

Study investigators noted that vascular disease was uncommon in both island populations and there was no evidence of the high saturated fat from coconut oil intake having a harmful effect in these populations. Importantly, blood triglyceride levels, a widely recognized cardiovascular disease risk factor, were low, averaging less than 50 mg/dL for both tribes.

The study?s authors concluded: ?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 ? Certainly, there is no reason based on this report, to alter the diet patterns of coconut eating groups in order to reduce coronary risk.? It is noteworthy that these tribes have historically consumed the same type of healthy diet and lifestyle followed by a majority of health-conscious dieters: consumption of omega-3-rich seafood, fruits and vegetables, relatively low-sodium intake, regular exercise, and absence of tobacco use. Under such conditions, a high intake of coconut oil appears to not cause blood cholesterol levels to soar and does not cause heart disease. Presumably, the same protection against heart disease would be afforded to those who adopt a similar diet (which includes significant levels of coconut oil) and lifestyle as practiced by the South Sea Island natives.

The Filipinos of the Bicol region of Luzon have the highest fat consumption from coconut oil in the Philippines?26 g daily on average. Researchers found that although Bicol natives had the highest serum cholesterol among Filipinos, it was below 200 mg/dl. Importantly, Bicolanos enjoy the lowest mortality from heart disease and strokes among all Filipinos [See: Florentino RF and AF Aguinaldo. Diet and cardiovascular disease in the Philippines. Paper presented at the Symposium on Medical and Nutritional Aspects of Coconut Oil. Philippine Coconut Authority Auditorium, Q. C. August 26, 1987.]

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No-Spin Bottom Line

No studies have ever shown that chronic use of coconut oil?even at the high levels consumed by South Sea Islanders?leads to atherosclerosis or heart disease. To the contrary, data from numerous studies suggest that coconut oil is not associated with clinical manifestations of atherosclerosis, and further, that dietary coconut oil may promote reductions in BMI, waist circumference, and abdominal obesity, all of which are widely acknowledged to reduce the risk of cardiovascular disease, metabolic syndrome, hypertension, and type 2 diabetes.

Noted researcher and nutrition authority, Dr. George Blackburn, (Harvard Medical School, New England Deaconess Hospital, Laboratory of Nutrition/Infection, Nutrition/Metabolism Laboratory, Cancer Research Institute, Boston), reviewed the published scientific literature on coconut oil and concluded that coconut oil is a neutral fat with respect to its atherogenic (heart disease) potential.

Dietitians and other healthcare professionals suffering from confirmation bias can spread false and/or questionable information using the Internet as easily as can bloggers with little or no formal nutritional training. In this case, the balance of published data thus far supports the position that coconut oil use, as part of a healthy diet and lifestyle, does not lead to unfavorable lipid profiles, heart disease, or obesity. Larger, long-term RCTs are required to confirm the observed health and weight-loss benefits of coconut oil.

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? Disclaimer: This is my informed opinion. I could be wrong. What do you think?

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Source: http://www.paleopharm.com/coconut-oil-hero-or-zero/

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