Dietitian providing nutrition support
(when you are unable to eat by mouth)


Nutrition support may sound like something dietitians are doing all the time. However, nutrition support in the dietitian world really refers to nutrition provided to a patient who is unable to eat via their mouth. This happens more often than you may think. 


There are two main types of nutrition support. The first choice would always be what is called enteral nutrition (also called tube feeding). This is for the patient who has a functioning gastrointestinal system (stomach and intestines) but for some reason is unable to use their mouth to eat. This happens when you are on a breathing machine in ICU, when you have neurological damage from a stroke or a traumatic brain injury, when you have had cancer or other disease in your mouth or your esophagus (the “pipe” between your mouth and stomach) or other issues. 


A feeding tube can be temporary or permanent. If it is temporary you most likely get a tube via one of your nostrils that goes down to your stomach or to the first part of your intestines. A permanent tube would be going straight into your stomach from the outside. 

Liquid nutrition formula and water is given via this tube to fully support your nutritional needs as well as hydration needs. Medication that is either liquid or crushable can also be given via the tube. 


Your dietitian will help select the right type of nutrition formula that will fit your needs and calculate how much of the formula as well as water that you should have each day. The dietitian will also give you instructions on how to use the tube if you are going home with it. There are several different ways that you can deliver the feedings practically. The reason why this type of feeding is always the first choice is that if you are not using your gastrointestinal system for a while the function will start to decline. You want to keep using it as much as possible. However, this is not always possible.


When you are unable to use the stomach and intestines there is another way to get nutrition called parenteral nutrition. This is nutrition delivered intravenously, meaning direct into your bloodstream via a vein. This is a dietitian's last resort. In order to receive full nutrition support this way it requires you to have a tube placed into your subclavian vein (it goes under your right collar bone into your superior vena cava) which carries blood from your head, neck, upper chest, and arms to the heart. Because of the direct access into a central vein like this it is considered a high risk treatment mainly due to infection risk. This type of nutrition is also very expensive. 


Once you have your central line in place the dietitian will analyze your medical situation and carefully assess your blood values. This type of nutrition can be highly customized if necessary as it is completely broken down. The dietitian has to consider how much volume to give directly into someone’s blood stream and specify how much of the macronutrients, vitamins, and minerals to give. We are no longer talking about carbohydrates and protein here, we are talking about the broken down versions meaning we specify dextrose, amino acids and what type of fat to provide. We are also specifying how much electrolytes such as potassium, sodium, phosphorus and such things to give and we can adjust the acetate and chloride balance and more.


Apart from being a high risk due to possibility of infection, the dietitian ordering this must have specialized training and should be discussing with the physician and pharmacist regarding the order. For example, if you are not careful, giving too much potassium to someone can cause heart arrhythmia and messing up the acid / base proportions could be lethal. You may not think that a dietitian could kill a patient but with wrongly ordered parenteral nutrition it is possible. There should always be more than one person looking at and approving a parenteral nutrition order. 


There is a lot more to say about nutrition support, this is just a peak into this world. If you are a dietitian reading this and you want to specialize in nutrition support I highly recommend the advanced CNSC certification. This is open both to US dietitians and international dietitians. I took this exam in 2017 and then worked in a hospital where the dietitians had order writing privileges. You can find more information about the certification here:

If you are looking to find the best information regarding nutrition support ASPEN (American Society for Parenteral and Enteral Nutrition) is your place to go:


This does not cover everything we do in nutrition support but it gives you a good overview.

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