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Nutritional supplements are defined as medical foods that are used to complement an individual's dietary needs. These products can be consumed orally or through enteral feeding devices. Enteral nutrition can be defined as the administration of liquid nutrition into the gastrointestinal tract via some type of feeding tube device? for example, through an orogastric or nasogastric tube.1 Enteral products (nutritional supplements) often contain complete nutritional replacement for patients who require tube feedings to meet specific nutritional needs due to various medical conditions, such as cancer or stroke. These products also provide adequate nutrition for individuals with impaired digestion.
Nutritional supplements also are extensively used by patients who require adjunctive nutritional sources to meet their dietary needs. Most recently, nutritional supplements are being marketed as meal-replacement products to individuals attempting to lose weight, those with active lifestyles, or those seeking high-protein supplements. For many individuals, the use of nutritional supplements is convenient, and these supplements are a better alternative to eating unhealthy foods or simply skipping a meal.
Currently, more than 100 commercial preparations are available for enteral feedings.1 There is a growing trend toward designing nutritional supplements in the form of puddings, nutritional bars, and beverages formulated to meet targeted nutritional needs, such as basic nutrition or certain medical conditions (Tables 1 and 2).
Nutritional Supplement Product Categories
The American Pharmaceutical Association's Handbook of Nonprescription Drugs states that enteral nutritional products may be classified in the following categories1:
?Polymeric formulas?the most frequently used nutritional supplements. They are designed for patients with normal digestive processes and contain macronutrients in the form of intact proteins, fatty acids or oils, and carbohydrates. Most individuals who require nutritional support tolerate and thrive with polymeric formulas.
?Oligomeric formulas?sometimes known as predigested (requiring minimal digestion) or elemental supplements. These formulas have proteins in the form of free amino acids or peptides. The carbohydrates are in the form of partially hydrolyzed starch, and the fat usually is a mixture of mediumchain and long-chain triglycerides. These formulas are lactose-free and do not contain fiber. Patients with digestive tract disorders such as Crohn's disease would be ideal candidates for these types of nutritional configurations.
?Modular formulas?formulated to supplement a single macronutrient content of an enteral food or formula. They can be utilized with other foods to increase the caloric and protein content consumed by an individual.
?Specialty formulas?various nutritional supplements designed to meet the specific needs of patients with specific disease states, such as diabetes and pulmonary, renal, and immune disorders. In general, these specialty formulas should be utilized only when an individual is under direct medical supervision. Diabetic formulas are designed for patients with glucose intolerance. Pulmonary formulas are formulated for patients with carbon dioxide retention and pulmonary conditions. Renal formulas are designed to decrease the risk of fluid overload by being calorie-dense; they have reduced concentrations of magnesium, potassium, and phosphorus. The most recent additions to the market are immune-enhancing formulas, which are still being evaluated.
The Role of the Pharmacist
Pharmacists should counsel patients thoroughly on the proper guidelines for using oral nutritional supplements. They should remind patients to promptly refrigerate opened products and to discard the unused portions after 24 hours to prevent microbial growth. Those using tube feedings should be instructed on proper aseptic technique with regard to tube-feeding supplies. Enteral feeding tubes should not hang for more than 12 hours at room temperature. The unused portion after this time frame should be discarded.
Pharmacists are vital to preventing drug-food interactions by thoroughly screening the patients'medication profile. One key interaction is associated with anticoagulant therapy, because some of the products may contain high levels of vitamin K. As the utilization and variety of these products increase, pharmacists are vital to ensuring that their patients select the appropriate product and use it correctly and that patients are monitored routinely by their physicians.
Ms. Terrie is a clinical pharmacy writer based in Slidell, La.