Coconut oil: can it really benefit sports performance?

Speaking as a Registered Dietitian and Sport and Exercise Nutritionist (SENr) the question of what is the best type of fat/oil to use is always a tricky one to answer as it requires a fundamental knowledge of the structure and nature of their fatty acid composition. That is because when we eat foods containing fat we are consuming a blend of their fatty acids which are classified according to their structure and the number of carbon atoms in their chain. In recent years research has focused on these different types of fatty acids and their properties as they may have different health benefits depending on the length of their carbon chains.

Heart health guidelines still currently advise using fats and oils with a high proportion of saturated fatty acids sparingly in order to keep total intakes of saturated fat at or below 10% of daily calories. Advice also includes keeping intakes of hydrogenated vegetable fats (including hydrogenated coconut/palm oil) in processed foods e.g. manufactured cakes, pastries and biscuits to a minimum.

Coconut oil is indeed one of the richest sources of saturated fat in vegetable oils with about 86-90% of all its fatty acids being saturated whereas olive oil, has a high proportion of heart-healthy monounsaturated fatty acids and small amounts of saturated fat.

However what is interesting about the saturated fatty acids in coconut oil is that around 60% are medium chain triglycerides (MCTs) which are metabolized differently to the saturated fatty acids found in butter, milk and animal fats which have shorter and longer carbon chains respectively. MCTs require fewer enzymes and bile acids for digestion and are transported directly from the gut to the liver where they are metabolised to provide a more readily available source of fuel for use by organs and exercising muscles compared to the shorter and longer chain fatty acids which are more typically stored as fat.

So is there any truth behind the claims for coconut oil promoting heart health, weight loss and athletic performance?

In recent years there has been a resurgence of interest in MCTs by athletes seeking to enhance endurance performance as well as exploiting an alternative energy source for those using high-protein, low-carbohydrate diets. However the hypothetical benefits may not necessarily provide the desired results in practice as a major downside of using MCTs is the associated nausea and gastric discomfort which may compromise exercise performance..

In terms of health research findings suggest that MCT’s might lower risk factors for heart disease in a similar way to the unsaturated fatty acids in olive oil by increasing levels of protective HDL-cholesterol however olive oil may have the edge as it contains a number health protecting polyphenols, vitamin E, and other natural health promoting antioxidants. A review published in Food Research International (2013) by Santos et al., described however, how common cooking methods including frying, boiling and microwave cooking can modify the chemical profile of olive oil reducing the potency of these antioxidants.

In terms of weight loss research using MCT’s on humans has suggested some potential benefits including a short-term increase in metabolic rate and increased satiety for the calories consumed however an important point to consider is that the research was conducted using neat distilled MCT oil which consists of caprylic acid (8 carbons) and capric acid (10 carbons) whereas coconut oil only contains about 10%-15% of these MCTs. Coconut oil has a high concentration of lauric acid (45%-50%) a 12-carbon chain) and the remaining fatty acids are made up of myristic acid (14 carbons), palmitic acid (16 carbons), and stearic acid (18 carbons). Furthermore, whilst MCTs do provide slightly fewer calories (8.3 kcals per gm) compared to other fats and oils which provide 9 kcals per gm a single 15ml tablespoon of either coconut oil or olive oil provides around 116 calories. So both need to be used in moderation as part of any weight management programme.

So is the current interest in coconut oil as the preferred choice of fat justified? Whilst a number of claims have been made there is no conclusive scientific consensus that coconut oil (as opposed to the distilled MCT oil that was used in the studies) does speed up metabolism, promote weight loss and heart health. So my advice to runners is to harness the benefits of both. Depending on the flavour required coconut oil can be used sparingly in cooking or baking for the potential benefits of its saturated MCT’s but don’t dismiss the health promoting benefits of monounsaturated fats and antioxidants in olive oil make as it makes for a healthier (and tastier) option as a salad dressing and food garnish.

Santos, C.S.P., et al., Effect of cooking on olive oil quality attributes

Food Research International (2013) http://dx.doi.org/10.1016/j.foodres.2013.04.014