Malnutrition is frequently associated with complications and adverse physiological health outcomes. Metabolically stressed patients have higher energy and protein needs than non-stressed patients. Both parenteral and enteral route has been shown to be beneficial to the patients. Enteral nutrition has been favored because it is cheaper, more physiological and is reported to be associated with fewer complications. Besides, supply nutrients intraluminally is important to strengthen the mucosal barrier and so might prevent bacterial translocation which is believed to be a major factor in the development of nosocomial sepsis, multiple organ dysfunction syndrome, and death. Patients who are clinically and mechanically able to tolerate enteral feedings should be fed enterally, especially immunonutritional product.

Although the world trend for nutritional support is leading toward more enteral than parenteral nutrition, parenteral nutrition remains as the only hope for patients with serious illness but not able to obtain enough nutrients from enteral nutrition.

Parameters used to monitor nutritional support include CBC, albumin and prealbumin, liver function, BUN/creatinine chemistries (glucose etc), cholesterol, triglycerides, Ca, Mg, P, iron indices, zinc and other trace elements, coagulation profile,vitamin levels, catheter site, food diary, fluid intake, urine and stomal/stool output, bone densitometry, weight, strength, stamina, endurance, and quality of life. Basically, those patients who had parenteral or enteral nutrition should have body weight measurement, nitrogen balance, visceral protein parameters and creatinine-height index to evaluate the effectiveness of such support.
Pharmacoeconomic evaluation (PE) has become popular in recent years to evaluate whether one treatment is cost-saving besides its claimed benefit. It is well established in the pharmaceutical industry. However, there are problems in applying PE in nutritional product because it is difficult to get survival benefit from nutritional support, to decide a patient is truly benefited from the nutrition, to decide which nutrient is beneficial, and also difficult in calculating the QALM or QALY. However, some study did show that immunonutrition influence treatment cost in GI surgery and critical illness.