What Are Medium-Chain Triglycerides?

Coconut oil is a major food source of medium-chain triglycerides.
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Medium-chain triglycerides, or MCTs, are a special type of fat that offers a variety of potential health benefits. Structurally, fats are basically chains of carbon atoms, and they can be categorized by the length of these carbon chains. Most dietary fat is in the form of long-chain triglycerides, or LCTs, which contain more than 12 carbon atoms. MCTs, by comparison, are shorter in length with only 6 to 12 carbon links. It is this smaller size that makes MCTs unique and gives them distinct advantages over other fats.

Sources of MCTs

Few foods contain MCTs. According to Sally Fallon and Mary Enig, authors of "Nourishing Traditions," small amounts of MCTs are found in butterfat, while coconut and palm oil contain much larger amounts. Over two-thirds of the saturated fat in coconut oil is comprised of MCTs. Supplements of concentrated MCT oil are widely available. Being saturated, they are stable and have a long shelf life.

Metabolism of MCTs

In "Advanced Sports Nutrition," Dr. Dan Benardot, a prominent sports nutritionist and researcher, explains how MCTs appear to behave more like carbohydrates than fats. Because of their small size and water-solubility, they require less energy and enzymes to be digested. Instead of being stored as fat, MCTs are easily absorbed and delivered to the liver where they are rapidly burned for energy. Consequently, as suggested by Benardot, MCTs may provide a quick source of energy, help mobilize body fat stores for energy, increase metabolic rate and spare muscle tissue.

Health Benefits of MCTs

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A review article in the "American Journal of Clinical Nutrition" notes that since the 1950s, MCTs have been used in the treatment of malabsorption syndromes such as cystic fibrosis, Crohn's disease, celiac disease and cirrhosis. This is due to their ability to bypass the steps ordinarily required for assimilation of fats. Because MCTs help to increase metabolism, they can be useful for weight loss. A recent study reported in "Obesity Research" compared MCTs and LCTs in 24 overweight men. Those men consuming a diet rich in MCTs experienced significantly more fat loss along with an increase in calorie-burning.

Athletes and MCTs

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While the potential of MCTs to aid weight loss can be beneficial to some athletes, there is conflicting evidence that MCTs impact performance. One study published in the "International Journal of Sports Nutrition and Exercise Metabolism" showed that consumption of MCT oil before a cycling time-trial was associated with improved performance. The researchers concluded that the cyclists' performance enhancement resulted from a switch from glycogen, or stored carbohydrate, to the fast-acting MCTs as their primary source of fuel. In contrast, a study published in the "Journal of Sports Medicine and Physical Fitness" found that well-trained runners did not show improved endurance or a change in energy metabolism when MCT oil was added to their diets.

Recommendations and Cautions

Coconut oil can be ingested alone or mixed in yogurt, juice or your favorite smoothie. Don't take more than 1 to 2 tablespoons, as more than this may produce stomach discomfort and possibly diarrhea. Also, coconut oil is a good cooking oil because it is less susceptible to damage in high heat. Consult your physician before taking any supplements of pure MCT oil.

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