Triglycerides, or fats, are often classified by their size as either short-, medium-, or long chain triglycerides. Short chain fatty acids (SCFAs) are found only in small amounts in food. In our bodies, they are produced in the intestines as a byproduct of carbohydrate and fiber digestion. SCFAs are used to feed the lining of the intestines which aids in digestion and nutrient absorption.
Long chain triglycerides (LCTs) are found in most of the fatty foods we eat including oils, fish, nuts/seeds, and meats. Most fats can be synthesized within the body if needed. However, two long chain fatty acids, linoleic acid and linolenic acid, cannot be made. These “essential fatty acids” must be consumed in the diet. During digestion, long chain fatty acids are broken down by hormones, pancreatic enzymes, and bile. Once digested and absorbed, LCTs are used by the body or stored as adipose tissue.
Medium chain triglycerides (MCTs) are fat molecules with 6-12 carbons. They are found naturally in foods including coconut oil, palm kernel oil, and dairy products. MCTs are significant because they are absorbed quicky and more readily than LCTs. This allows the fats to be quicky utilized by the body. This may have useful impacts on health in pediatrics and adults with a variety of GI conditions.
Pancreatic Insufficiency and Liver Disease
Digestion of most fats requires pancreatic enzymes and bile acids. In the case of pancreatic insufficiency or liver disease, this function may be compromised causing malabsorption of fats and leading to diarrhea. Because MCTs are absorbed directly into the liver bypassing this process, MCT supplementation may be a way to provide calories from fat for someone who is not adequately absorbing fat from the diet.
Short Bowel Syndrome
Short bowel syndrome (SBS) – defined by a significant decrease in the length of the small intestine, usually following a surgical resection – can lead to significant malabsorption of nutrients, diarrhea, and malnutrition. Most nutrient absorption from all foods, including fats, takes place in the small intestines. Many people with SBS require nutritional supplementation from tube feeding or TPN. Due to the passive and quick absorption of MCTs, using foods or formula with increased MCTs can improve nutritional status and diet tolerance for someone with SBS.
Protein Losing Enteropathy
Protein Losing Enteropathy (PLE) can be caused by a variety of conditions and results in intestinal loss of protein. Oily, smelly diarrhea and malnutrition can result from PLE. Supplementation with MCT oil has been shown to increase serum protein levels and help manage symptoms of PLE.
Malnutrition can be a common side effect of malabsorption and diarrhea. Malabsorption can be related to SBS, Crohn’s, PLE or other conditions. Fats in the diet provide the most concentrated calories so a high fat diet is often recommended for someone who is underweight or malnourished. Especially when a high fat diet may not be well tolerated, MCT supplementation can support weight gain. Even if malnutrition is not caused by malabsorption or diarrhea, MCT oil may be a good option to add additional calories to foods or formula as it has minimal flavor and mixes easily into food or drink.
In contrast to providing additional calories for undernutrition, replacing LCTs with MCT sources in an overall calorie restricted diet may aid with weight maintenance for those with obesity. As previously discussed, MCTs are absorbed more quickly than LCTs which results an increase in leptin and PYY – the hormones that tell your brain you are full – and a decrease in ghrelin – the hormone that tells your brain you are hungry. This can increase satiety during and after a mealtime leading to less intake overall. Additionally, because the MCTs are more readily used for energy, we store less of them as adipose tissue compared to LCTs.
In conclusion, medium chain triglycerides can provide a quick source of energy from fat. Their unique properties may be especially relevant for those who have difficulty digesting fat and have accompanying diarrhea. However, the use of MCT supplementation has been shown to support nutrition in a variety of other conditions. When used for intolerance of LCTs, MCT oil should be considered over foods containing MCTs as the food sources contain both LCTs and MCTs. In the long term, long chain triglycerides are also important in the diet as absence of essential fatty acids can lead to essential fatty acid deficiency. Overall, when possible, a variety of foods from carbohydrates, fats, and proteins should be encouraged to maximize nutritional status.