By Cliff Harvey ND
In a recent New Zealand Herald online article, Dave Shaw, a registered dietician, says this of coconut and its associated oils:
“Everyone's talking about coconut goods at the moment - milk, oil, cream. There are claims they can solve everything from arthritis to cardiovascular disease. There's talk that coconut milk contains a high content of medium chain fatty acids that are metabolised differently than other saturated fats. The truth is, there isn't enough evidence to back the benefits, and a more likely outcome is that you'll pack on the pounds from the additional fat you're eating.”
Coconut Oil (CO) contains around 65% of its fat from Medium Chain Triglycerides (MCT) – most especially lauric acid, but also smaller amounts of capric, caprylic and caproic acid. These medium chain triglycerides and the associated fatty acids are highly saturated, and so have been targets of the unfounded ‘anti-fat’ and ‘anti-saturated-fat’ dogma that has pervaded dietetics.
MCTs have in fact been shown to promote ketonaemia and functional low-grade ketogenesis , a state of fat-adaptation allowing a greater rate of fat-loss and increased cognition, neuroprotection and cardio=protection amongst other benefits. As early as 1986 MCTs have been shown to increase metabolic rate more than the Long Chain Triglycerides (LCT) (1) which are the most common dietary fatty acids in the modern diet. A 2010 review concluded “dietary MCFAs/MCTs suppress fat deposition through enhanced thermogenesis and fat oxidation in animal and human subjects. Additionally, several reports suggest that MCFAs/MCTs offer the therapeutic advantage of preserving insulin sensitivity in animal models and patients with type 2 diabetes.” (2).
The fat loss benefits of MCT ingestion have been demonstrated in 2008 research reported in the prestigious American Journal of Clinical Nutrition in which forty-nine overweight men and women, aged 19–50 years of age, consumed either 18–24 grams per day of MCT oil or olive oil as part of a 16 week weight loss programme. Those consuming MCT as compared to olive oil had significantly lower end-point body weight, and a greater loss of fat including both trunk fat and intra-abdominal fat (the most dangerous fat stores for cardiac rick factors) (3).
A further 2012 study by the lead author of the aforementioned research demonstrated greater losses of upper-body adipose tissue with a trend towards greater losses of overall adipose tissue in those taking MCT as compared to olive oil. Early average fat oxidation was also higher in the MCT group. The authors concluded that “Consumption of a diet rich in MCTs results in greater loss of Adipose Tissue compared with LCTs, perhaps due to increased energy expenditure and fat oxidation observed with MCT intake. Thus, MCTs may be considered as agents that aid in the prevention of obesity or potentially stimulate weight loss.”(4).
Other research has shown varied effects including reductions in weight and improvements in insulin sensitivity in type 2 diabetics (5).
This brief review is by no means exhaustive and there are increasing volumes of evidence supporting the use of MCTs of the type found in coconut oil as a positive adjunct to a healthy diet. It is further being demonstrated exhaustively that existing dietetic guidelines for reducing saturated fat intake along with recommendations for a high carbohydrate, low-fat and polyunsaturated dominant diet are worsening, not improving public health outcomes.
1. Seaton, T. B., Welle, S. L., Warenko, M. K., & Campbell, R. G. (1986). Thermic effect of medium-chain and long-chain triglycerides in man. The American journal of clinical nutrition, 44(5), 630-634.
2. Nagao, K., & Yanagita, T. (2010). Medium-chain fatty acids: Functional lipids for the prevention and treatment of the metabolic syndrome. Pharmacological Research, 61(3), 208-212. doi: http://dx.doi.org/10.1016/j.phrs.2009.11.007
3. St-Onge, M.-P., & Bosarge, A. (2008). Weight-loss diet that includes consumption of medium-chain triacylglycerol oil leads to a greater rate of weight and fat mass loss than does olive oil. The American journal of clinical nutrition, 87(3), 621-626.
4. St-Onge, M.-P., Ross, R., Parsons, W. D., & Jones, P. J. H. (2003). Medium-Chain Triglycerides Increase Energy Expenditure and Decrease Adiposity in Overweight Men. Obesity Research, 11(3), 395-402. doi: 10.1038/oby.2003.53
5. Han, J. R., Deng, B., Sun, J., Chen, C. G., Corkey, B. E., Kirkland, J. L., . . . Guo, W. (2007). Effects of dietary medium-chain triglyceride on weight loss and insulin sensitivity in a group of moderately overweight free-living type 2 diabetic Chinese subjects. Metabolism, 56(7), 985-991. doi: http://dx.doi.org/10.1016/j.metabol.2007.03.005