As coconut oil has gained in popularity, articles written on the possible health benefits of this oil have skyrocketed. Coconut oil has been labeled as everything from a weight loss supplement to a cure for cancer and facial moisturizer. Yet, the numbers of reliable clinical trials to back up these claims are scarce. In this post I am going to focus on a claim targeted towards athletes: “coconut oil improves athletic performance”… doesn’t it?
Coconut oil is primarily made up of saturated fats. There are three categories of saturated fats: short chain fatty acids, medium chain fatty acids, and long chain fatty acids. The length of chain refers to the number of carbon atoms present, 6 or fewer (short), 8-10 (medium), or 12 or more (long). Coconut oil contains 63% medium chain saturated fatty acids, 30% long chain saturated fatty acids, and 7% long chain unsaturated fatty acids. Primarily made up of saturated fats, this composition sets coconut oil apart from other oils, especially in the oil’s medium chain triglyceride (MCT) content. Many researchers believe the MCT content is what gives coconut oil health-boosting properties.
The abbreviation, MCT, may sound familiar. Like coconut oil, MCT oil has emerged as a dietary supplement. While MCTs are naturally present in coconut oil, palm oil, human breast milk, and full fat cows or goats milk, pure MCT oil is hydrolyzed from palm and coconut oil.
Medium chain triglycerides are more readily absorbed in the intestines compared to long chain triglycerides. For this reason, MCT supplementation is commonly prescribed to cystic fibrosis or epilepsy patients, and those with conditions that affect nutrient absorption in the intestines.
Some scientists claim that replacing long chain triglycerides with MCTs in one’s diet can aid in weight loss through fat oxidation and improved thermogenesis. Compared to LCTs, a meta-analyses published in the Journal of the Academy of Nutrition and Dietetics found a diet including MCTs over an average of ten weeks reduced total body fat, subcutaneous fat, and visceral fat as well as waist and hip circumferences. However, no significant difference in blood lipids was found between diets containing LCTs or MCTs. While a diet high in MCTs may actually help with fat loss, MCTs are just as high in calories as other fats. Therefore, if not consumed in moderation, MCTs can cause weight gain.
With easier absorption plus increased fat oxidation and thermogenesis, can MCT oil improve athlete performance? Many internet articles claim MCT oil to be beneficial to endurance athletes. Websites such as rebootedbody.com want to convince you that MCT oil supplementation is a must for athletic performance; however, four published clinical trials say otherwise.
The first study published in the International Journal of Sports Nutrition and Exercise Metabolism measured the respiratory exchange ratio (RER) and maximum aerobic capacity (VO2) in eight ultra-endurance cyclists. The cyclists performed at timed intervals on two separate occasions. During the first set of timed intervals, the cyclists were given either 75g of carbohydrate or 32g of pure MCT oil, followed by 200mL of a 20% carbohydrate solution or a 4.3% MCT + 10% carbohydrate solution every 20 minutes during the intervals. Results found no difference in RER or V02 between the MCT and carbohydrate trials. GI symptoms occurred in 50% of the MCT trials.
The second study published in the American Journal of Clinical Nutrition included seven cyclists that performed four separate exercise trials while consuming either a 10% carbohydrate solution, 10% carbohydrate-electrolyte + 5% MCT solution, a 5% MCT solution, or a placebo. Results found no differences in performance between the carbohydrate, carbohydrate + MCT, and placebo solutions. However, the MCT solution had a negative effect on performance with a 17-18% lower rate than the other solutions. Plus, the carbohydrate + MCT and MCT-only solutions did not raise the rates of fat or carbohydrate oxidation or utilization. GI symptoms occurred in association with MCT solutions.
The third study published in the Journal of Sports Medicine and Physical Fitness assessed trained runners that performed a maximal and endurance treadmill test after consuming a dietary supplement containing either 56g of corn (LCT) oil or 60g of MCT oil for two weeks. After the tests, the runner’s blood was taken to measure blood concentrations of lactate, glucose, beta-HBA, free fatty acids, glycerol, and triacylglycerols. Respiratory exchange rate (RER) was measured during exercise and performance was measured by length of run before exhaustion. Results found no difference in blood concentrations between the LCT and MCT trials. No significant difference in RER or performance was found between the two trials.
The fourth study published in the International Journal of Sports Nutrition measured blood concentrations of free fatty acids and beta-HBA, and exercise performance in 9 cyclists consuming either a 10% carbohydrate solution, 10% carbohydrate + 1.72% MCT, or 10% carbohydrate + 3.44% MCT solution. Cyclists consumed 400ml at the start of exercise and an additional 100ml every 10 minutes. Results found the consumption of MCT solutions raised blood concentrations of free fatty acids and beta-HBA. There was no difference in performance between the carbohydrate and carbohydrate + MCT groups. No gastrointestinal symptoms were reported.
The bottom line: coconut oil is a 90% saturated oil with a high MCT content. MCTs have potential health benefits, and can be hydrolyzed from coconut oil to produce pure MCT oil. Currently, research does not support that coconut oil or pure MCT oil supplementation enhances athletic performance.
This post written by: Ellen Wittneben, RDKate Dietetic Intern
Your Nutrition Coach,
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