Difference between Enteral and Parenteral Nutrition

Nutrition is mainly taken by mouth in a healthy individual. Food particles are broken down in mouth into small pieces and then are carried to stomach and intestines where majority of absorption of food nutrients and water takes place. Waste products are then excreted through rectum and anal canal. But in diseased individual, who cannot take food through oral cavity, for example one who is vomiting excessively, we need to administer nutrients through enteral or parenteral routes. Each one of these routes carries its own risks and benefits but we choose between the two modalities on the basis of one’s requirement.

Enteral Nutrition

The term ‘enteral feeding means delivery of nutrients into the GIT.  The alimentary tract should be used whenever possible. This can be achieved with oral supplemental feeds (sip feeding) or with a range of tube feeding methods that make food reach into the stomach, duodenum and jejunum.  A variety of formulas are available for enteral feeding. These have different level of energy contained in them, osmolarity, fat and nitrogen content. Most of them contain 1 to 2 kilo calories per mL and up to 0.6 g per mL of proteins. There are two types of these formulas. First is polymeric which contain intact protein and hence require digestion. Second is monomeric which contain nitrogen in the form of amino acids or peptides.

Parenteral Nutrition

This is abbreviated as ‘TPN’ and is defined as a source of all nutritional requirements by means of intravenous routes and without the use of GIT. It is indicated when energy and protein needs cannot be met by enteral administration of these substances. The most frequent indication relates to those patients who have undergone excessive resection of small intestine, who have a leak in the intestine or who have prolonged intestinal failure. It has got two routes of delivery. One is central and other is peripheral. In the central route, catheter is inserted into subclavian, internal or external jugular vein. While in peripheral route, small veins in the peripheral part of the body are used.

Enteral VS Parenteral Nutrition

Definition:

Enteral feeding means administration of nutrients through GIT.

Parenteral nutrition means administration of nutrients through intravenous routes.

Types:

Enteral nutrition has following types; sip feeding, tube feeding, tube insertion and gastrostomy.

Parenteral nutrition has following types; central and peripheral.

Calories:

Enteral formulas have 1-2 kilo calories per mL.

Parenteral feeds have 25 to 30 kilo calories per kg per day.

Indications:

Enteral feeding is indicated when a patient cannot take anything per oral for 5 to 7 days.

Parenteral nutrition is indicated in the same period but if enteral feeding is not possible.

Complications:

Enteral feeding can cause GIT disturbances, electrolyte disorders and infections.

Parenteral feeding can cause over feeding, sepsis, decreased or increased blood sugar level.

Re-feeding syndrome:

It is a form of electrolytes and water shift which occurs less commonly with enteral feeding.

It is more common with parenteral feeding.

Conclusion

The indications for enteral and parenteral feeding are simple. But both have their own complications.