What are the osmolarity and caloric density of Tolerex (elemental formula) versus PediaSure (polymeric formula) versus Peptamen Junior (peptide-based formula)?

Osmolality and Caloric Density of Tolerex, PediaSure, and Peptamen Junior

Tolerex has the lowest osmolality at approximately 215 mOsm/kg H₂O with 1 kcal/mL caloric density, PediaSure has moderate osmolality around 390-405 mOsm/kg H₂O with 1 kcal/mL, and Peptamen Junior has an osmolality of approximately 315-370 mOsm/kg H₂O with 1 kcal/mL.

Comparison of Formulas by Type

Elemental Formula (Tolerex)

• Elemental formulas like Tolerex contain free amino acids, making them highly digestible for patients with severe malabsorption 1
• Tolerex has a relatively low osmolality of approximately 215 mOsm/kg H₂O, which makes it less likely to cause osmotic diarrhea 1
• Standard caloric density is 1 kcal/mL (30 kcal/oz) 1
• Elemental formulas are typically used after failure of other diets, severe malabsorption, or transition from parenteral nutrition 2

Polymeric Formula (PediaSure)

• PediaSure is a nutritionally complete standard formula containing intact proteins 1
• Has a higher osmolality of approximately 390-405 mOsm/kg H₂O, approaching the upper recommended limit of 450 mOsm/L for infant formulas 1
• Standard caloric density is 1 kcal/mL (30 kcal/oz) 1
• Contains whole proteins, long-chain triglycerides, and carbohydrates primarily as polysaccharides 1

Peptide-Based Formula (Peptamen Junior)

• Peptamen Junior contains peptides and medium-chain triglycerides to facilitate absorption in conditions like malabsorption or short bowel syndrome 1
• Has a moderate osmolality of approximately 315-370 mOsm/kg H₂O 1
• Standard caloric density is 1 kcal/mL (30 kcal/oz) 2
• Well-tolerated in children with complex diseases featuring malabsorption and/or after failure of polymeric diet 2

Clinical Considerations

Osmolality Concerns

• The American Academy of Pediatrics recommends that infant formulas have an osmolality of less than 450 mOsm/L to reduce risk of osmotic diarrhea 1
• High osmolality formulas (>400 mOsm/kg) may increase the risk of necrotizing enterocolitis in vulnerable infants 3
• Increasing osmolality up to 700 mOsm/kg leads to a dose-dependent decrease in intestinal barrier function 1
• Medications and carbohydrate modules added to formulas can significantly increase osmolality 1

Caloric Density Modifications

• Standard infant formulas typically provide 20 kcal/oz, while these specialized formulas provide 30 kcal/oz 4
• For infants with higher energy requirements, caloric density can be increased to 24-30+ kcal/oz 4
• When concentrating formulas, the effect on osmolality is linear, allowing for prediction of osmolality at different concentrations 3
• Over-concentrated formulas may exceed 400 mOsm/kg, potentially causing feed intolerance 3

Formula Selection Algorithm

1. For patients with severe malabsorption or GI dysfunction:

   • Start with Tolerex due to lowest osmolality and free amino acid composition 1

2. For patients with moderate malabsorption or pancreatic insufficiency:

   • Consider Peptamen Junior with its peptide-based protein and medium-chain triglycerides 1, 2

3. For patients with normal digestive function requiring nutritional support:

   • PediaSure is appropriate with its intact protein and standard nutrient profile 1

Pitfalls to Avoid

• Avoid rapid advancement of formula concentration, especially with higher osmolality products like PediaSure 4
• Do not exceed 4 g/kg/day of protein in young infants due to risk of acidosis related to immature kidneys 1
• Be cautious when adding modules (carbohydrates, proteins) to formulas as this can significantly increase osmolality beyond safe levels 3
• Monitor for signs of feed intolerance such as abdominal discomfort and diarrhea when initiating any of these formulas 5