Types of Enteral Nutrition

Enteral formulas may be referred to via several names, including “enteral nutrition formulas” or “peptide-based diets.” The primary difference in these formulas is found within the protein and fat content and the size and structure of the protein equivalent.  

Elemental Formulas  

Elemental formulas are nutritionally complete, which means they contain all of the nutrients needed to maintain nutritional sustenance. They are unique in that the protein equivalent and fats (medium chain triglycerides, or MCTs) are broken down to their simplest form, making them easier to digest. Because elemental formulas are made from the building blocks of foods, they are considered to be pre-digested formulas — which is why they require minimal digestive function. Most commonly, patients on an elemental formula or an elemental diet rely on the formula as their sole source of nutrition for two to three weeks. Therefore, it’s important to complete the diet under close medical supervision. Physicians’ Elemental Diet™ is an orally administered elemental formula. Other examples of elemental formulas include Vivonex® T.E.N. and Vivonex® PLUS.  

Semi-Elemental Formulas  

Semi-elemental formulas contain amino acids of varying length, simple carbohydrates, and MCTs. They are partially pre-digested but not fully pre-digested. An example is Peptamen AF®.  

Polymeric Formulas  

Polymeric formulas contain whole proteins, complex carbohydrates, and long chain triglycerides, meaning the nutrients are intact and have not been broken down, which requires additional work by the digestive system. For individuals who have full digestive function, there is no issue digesting a polymeric formula. They may also include fiber, and depending on the formula, may be consumed orally or via a tube. Polymeric formulas are often used for longer periods of time (6+ weeks) and are less expensive than elemental or semi-elemental formulas. Boost® and Ensure® are examples of high calorie polymeric formulas you may be familiar with.  

Specialized Formulas  

A variety of specialized formulas are also available. These are nutritionally complete products, designed to meet the needs of individuals with specific health conditions. The availability varies widely. One such example is Magnacal Renal, which is formulated specifically for renal support.  

*Vivonex TEN, Vivonex PLUS, Boost, and Peptamen AF are registered trademarks owned by Societe des Produits Nestle S.A., Vevey, Switzerland.  
Ensure is a registered trademark owned by Abbott Laboratories Corporation Illinois