reactions in the body then break down food into molecules that enter the blood-
stream and are distributed to different parts of the body where they are used to
sustain life.
Some nutrients are used for cell growth and cellular functions. Other
nutrients become involved in enzyme activities and carbohydrate-fat-protein
synthesis. Nutrients are used to contract muscles and help wounds to heal.
They also play a critical role in the integrity of the GI tract and in the immune
system.
Think of nutrients as fuel for your car. Fuel is used as you drive your car. The
same is true about your body. Your body uses nutrients to go about daily activi-
ties. And just like your car, your body can continue to operate without a full
complement of nutrients—that is, without a full tank of gas. A healthy, well-
nourished person has a nutritional level to last 14 days before they begin to show
signs of malnutrition. That is, your full tank of gas will last 14 days.
However, there comes a point when your performance sputters—the level of
nutrients fall below the level needed to sustain your daily activity. You simply run
out of fuel and become fatigued, irritable, and exhibit an abnormal appearance.
This is referred to as a nutritional deficit.A nutritional deficit can occur from
a number of situations. The most obvious is not eating a balanced, nutritional
diet. However, there are less apparent reasons that cause a nutritional deficit.
These are surgery, trauma, malignancy, and other illnesses that break down
(catabolize) the body.
The effect of a nutritional deficit can be dramatic. The body needs nutrients
to recover from trauma and disease. A nutritional deficit prolongs healing and
severe cases can prevent total recovery. Critically ill patients have sufficient
nutrients to sustain them for a few days to a week before they begin to show
signs of nutritional deficit.
Healthcare professionals provide nutritional support therapy for patients who
are at risk for nutritional deficit. Nutritional support therapy replaces nutrients
that the patient has lost and thereby provide the patient with the fuel needed for
a full recovery.
A nutritional deficit is called a negative nitrogen balance, which means that
the patient lacks sufficient nitrogen to fight infectious disease. Healthcare pro-
fessionals treat patients who are at risk for negative nitrogen balance by provid-
ing the patient with nutrients before the imbalance occurs. The patient is then
able to fight infectious diseases.
A common misnomer is that dextrose 5% in water (D5W), normal saline, and
lactated Ringer’s solution provide nutrients to the patient. However, these intra-
venous fluids are not forms of nutrients. These are electrolytes and fluids.(^184) CHAPTER 11 Nutritional Support Therapies