Back in the 1980s, one of the more popular bodybuilding supplements was medium-chain triglycerides (MCT). I got my introduction to MCT supplements when a well-known trainer in Cincinnati sent me a bottle. Although he sent me a bottle of MCT, he didn't provide precise dosing instructions. I still remember the stomach ache I felt after ingesting a tablespoon of MCT. I consider the pain I felt secondary only to having diverticulitis many years later. What I didn't realize was that larger doses of MCT have a caustic effect on stomach tissues and can produce the mother of all stomach aches, as I unwittingly discovered. Although popular for years among bodybuilders and athletes, MCT gradually fell out of favor, probably because many of those who tried it made the same mistake I did of taking too large a dose. But MCT has made a comeback recently, not as direct MCT supplements, but rather as coconut oil. Many health benefits are being ascribed to ingesting coconut oil, including an ability to boost fat-burning efforts. The "magical" active ingredient in coconut oil is MCT. Indeed, direct MCT supplements are made by extracting the MCT found naturally in coconut oil and producing a purer form of MCT marketed as "MCT oil."
But what is MCT and what makes it special? They were not developed for bodybuilding or sports purposes, but rather to treat digestive malabsorption problems. Most of these problems were marked by an inability to absorb dietary fat. MCT allowed complete uptake because its route of absorption differed from that of other fat. Indeed, it has often been called the "fatless fat" because of its typical uptake speed into the body. It's fat that acts more like a carbohydrate. MCTs are called "medium-chain triglycerides" because of their structure. The term "triglyceride" refers to a structure that involves three fatty acids attached to a glycerol backbone, and they come in three primary varieties. These include long-chain triglycerides, such as those found in fish oil; short-chain triglycerides, which are produced mainly by the intestinal microbiome, but also exist in some foods; and medium-chain triglycerides. The number of carbons in the fat structure determines whether the fat is long, short, or medium-chained. Any type of triglyceride is either stored as fat or burned for energy. The type of fat that comprises stored body fat is mainly saturated fat, the same type of fat you see in meat and other sources. Most of the fat consumed in the diet are long-chain triglycerides, containing 13 or more carbons. Short-chain fatty acids have only 6 carbons or less, and MCTs contain 6 to 12 carbons.
The primary MCTs are the following:
- C6: caproic acid or hexanoic acid
- C8:
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