Enteral Nutrition:

First of all, normal oral ingestion belongs into this group, as well as nutrition with a feeding tube.
If an oral intake of food is not possible due to problems swallowing or problems with the oesophagus, nutrients can be supplied via a nose tube, for example. Alternatively, the patient can be fed with a tube that is directly inserted into the stomach through the abdominal wall (PEG-tube) or the small intestine (PEJ- or FCJ-tube). The planning of long-term enteral nutrition and the insertion of a permanent tube is performed by a doctor. The major advantage of this form of artificial nutrition is the ongoing use of the intestine, which should be used for the intake of nutrients whenever possible. The intestine functions as an important passage control (intestine barrier) for all nutrients and thus is the first step of digestion and selection of nutrients taken in by the body. An intact intestine barrier is also very important for the protection of the body against invading microorganisms.

Parenteral Nutrition:

Parenteral nutrition generally means intravenous nutrition. It is necessary when nutrients can’t be taken in via the gastrointestinal tract. Possible reasons are widespread inflammation of the intestine, an operation in the abdominal cavity or sever, unstoppable diarrhoea over a long period of time.

• Since digestion in the gastrointestinal tract is circumvented, all supplied nutrients have to be completely digested. Protein is supplied as protein building blocks, and carbohydrates as glucose.
• The mixture has to be adjusted to the need of the respective patient, since an 'I am full' regulation is not possible.
• The mixtures have to be absolutely sterile, as they are directly delivered into the venous blood system and invading germs would cause severe infections.