Why I Don't Eat Coconut Oil

I don’t eat coconut oil.  

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I also don’t eat any other oils, as I follow a whole food plant-based diet. Oil is a highly-processed product which is extracted from fruits, nuts and seeds, and I’d rather eat the fruit/nut/seed whole, and get the benefits of the fibre and phytochemicals (beneficial plant compounds).

The delicate oils in these foods are also highly unstable, hence why nature keeps them protected from light and heat (and hence oxidation) by wrapping a nifty little coating or shell around the nut/seed/fruit. Great work, nature. But what do humans do? We extract the oil from these wonderful whole plant foods and then package it in clear plastic or glass bottles where sunlight and heat can slowly destroy it. Nature 1; Humans 0. 

Pure oil is also the most concentrated source of energy (calories or kilojoules) you can consume of any food on the planet, at 612kJ/146 calories per tablespoon. The only two fats that we absolutely must get through our diet (i.e., the essential fatty acids) are omega-3 and omega-6, which can be found in a multitude of plant foods, such as ground flaxseed (rich in omega-3) and sunflower seeds (rich in omega-6). We have no dietary requirement for monounsaturated or saturated fats, as we can make them ourselves. But let’s get back to coconut. 

Coconut oil is 100% fat, which gives it an energy value of 3,700kJ/880 calories per 100mL. Yowza. 92% of the fat in coconut oil is saturated (which means it the fatty acids don’t contain any double bonds).

'But it’s a different type of saturated fat that is metabolised differently!' I hear you say. The ‘different type’ refers to the lauric acid, which only makes up between 45 and 48% of the fatty acids (fats) in coconut oil. So what are the other 52-55%? Myristic acid (14-18%), palmitic acid (7.5-9.5%), oleic acid (6-8.2%), caprylic acid (7.8%), capric acid (7.6%), stearic acid (5%) and linoleic acid (aka omega-6) (1-2%). Of interest is the fact that myristic and palmitic acid (both saturated fats) make up between 21.5% and 27.5% of the fats in coconut oil, and these two fats are the ‘chief saturated fatty acids implicated in cholesterol elevation, according to a FAO report (2010)(1). 

Fatty acids are classed as either short, medium or long-chain, depending on the number of carbon atoms they have. Lauric acid, with its 12 carbon atoms, is often labeled a medium-chain fatty acid (or a medium-chain triglyceride when it is attached to a glycerol backbone), which I will discuss later. 'Metabolised differently' refers to the fact that as medium-chain fatty acids are quite small, they are soluble in water, compared to long-chain fatty acids. As they are water soluble, they are absorbed directly into the hepatic portal (blood) circulation and proceed directly to the liver to be metabolized, as compared with long-chain fatty acids which after incorporation into micelles are absorbed into the lymphatic system.

The thing is, there is a marked decrease in solubility of fatty acids as they get longer than only 10 carbon atoms, and lauric acid contains 12 carbon atoms, hence, lauric acid actually act more like a long-chain fatty acid in our gastrointestinal tract (2).

Hmmm, okay, so the above seems to refute all that ‘metabolised differently’ talk, but what about its effect on cholesterol levels? Coconut oil raises total cholesterol levels (not good), and although a large part of this comes down to the fact that is tends to raise HDL cholesterol (good), it does however slightly elevate LDL cholesterol (not good)(3)(4)(5). Hmm. Basically, it’s not as bad as butter (which raises LDL cholesterol (bad)), and certainly not as bad as trans fats (which raise LDL cholesterol (bad) and lower HDL cholesterol (double whammy bad), but it’s also not as good as polyunsaturated fats, which can both raise HDL cholesterol (good) and reduce LDL cholesterol (bad). Furthermore, a large systematic review and meta-analysis of randomised controlled trials (i.e., the highest form of evidence) by Mozaffarian et al concluded that replacing saturated fats with polyunsaturated fats would significantly reduce rates of coronary heart disease (CHD)(6). I’m not talking about cooking with canola oil here, but rather eating whole foods that contain these fats such as walnuts in place of saturated fats such as coconut oil. Simple. 

And how do I feel about coconut milk? Good, as it’s a whole food product, but in moderation, as it’s still a high-fat food (with around 20g fat and 825kJ/198cals per ½ cup or 125mL). I use coconut milk in my curries, but I’m certainly not doing so to reap any perceived benefits of the saturated fat.

Coconut milk and cream are staples in numerous tropical countries such as India, Sri Lanka, the Philippines and Papua New Guinea and have been for centuries. Coconut oil has not. The diet and lifestyle habits of one such population - the people of Kitava island of Papua New Guinea – was extensively studied in the 1990s by a group of Swedish researchers as they were consuming a traditional diet (including coconut products) and had very low rates of chronic diseases including diabetes and heart disease (7). However, these studies highlight the importance of thinking outside of the square when looking at population-based (epidemiological) studies: the people of Kitava also had a low total fat intake of 21% energy (well, low by Western standards anyway), consumed a whole food diet (of fruit, vegetables, fish and coconut), had low BMIs, were active in their work as horticulturalists and drank no alcohol. Hence, it’s irresponsible to look at one population whose fat intake comes primarily from coconut and make assumptions about the healthiness of coconut products without also considering other diet and lifestyle factors.

In my opinion, there is certainly no health benefit to be had from adding coconut oil to your diet. If you do cook with fat or oil, it’s a good choice as it’s very stable and resists oxidation at high temperatures, but I’d only add the minimum amount required, and I certainly wouldn’t go eating it by the spoonful! 

(This post was inspired by the recently-released New Zealand Heart Foundation’s evidence paper titled ‘Coconut Oil and The Heart’, which is the best summary of the available evidence I’ve seen. You can read it here.)

References

1.         Joint FAO/WHO Expert Consultation on Fats and Fatty Acids in Human Nutrition. Fats and fatty acids in human nutrition: report of an export consultation. Rome: Food and Agriculture Organization of the United Nations; 2010.

2.         Eyres, Laurence. Coconut Oil and The Heart. 2014 Sep; Accessed November 26 2014. Available at: http://www.heartfoundation.org.nz/uploads/Evidence_paper_coconut_August_2014.pdf

3.         Effects of dietary coconut oil, butter and safflower oil on plasma lipids, lipoproteins and lathosterol levels. Publ Online 25 August 1998 Doi101038sjejcn1600621 [Internet]. 1998 Aug 25 [cited 2014 Nov 26];52(9). Available from: http://www.nature.com/ejcn/journal/v52/n9/abs/1600621a.html

4.         Fisher EA, Blum CB, Zannis VI, Breslow JL. Independent effects of dietary saturated fat and cholesterol on plasma lipids, lipoproteins, and apolipoprotein E. J Lipid Res. 1983 Aug 1;24(8):1039–48.

5.         Reiser R, Probstfield JL, Silvers A, Scott LW, Shorney ML, Wood RD, et al. Plasma lipid and lipoprotein response of humans to beef fat, coconut oil and safflower oil. Am J Clin Nutr. 1985 Aug 1;42(2):190–7.

6.         Mozaffarian D, Micha R, Wallace S. Effects on Coronary Heart Disease of Increasing Polyunsaturated Fat in Place of Saturated Fat: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. PLoS Med. 2010 Mar 23;7(3):e1000252.

7.         Lindeberg S, Nilsson-Ehle P, Vessby B. Lipoprotein composition and serum cholesterol ester fatty acids in nonwesternized melanesians. Lipids. 1996 Feb 1;31(2):153–8.