Which amino acids must be included in a parenteral solution?

In the context of parenteral nutrition, especially for individuals who cannot obtain nutrients through the gastrointestinal tract, it is essential to include essential amino acids in the solution. Among the amino acids listed in option B, tryptophan, phenylalanine, threonine, and isoleucine are classified as essential amino acids. Essential amino acids cannot be synthesized by the body and must be obtained from the diet or supplementation.

Including these specific amino acids in a parenteral solution is crucial for maintaining protein synthesis, supporting overall health, and preventing deficiencies during periods when oral intake is not possible. Tryptophan plays a role in neurotransmitter synthesis, phenylalanine is important for the synthesis of other amino acids and proteins, threonine is vital for immune function and protein synthesis, and isoleucine is necessary for muscle metabolism and energy production.

The other options do not adequately include all essential amino acids. For example, while some amino acids listed in those options may be beneficial, they do not fulfill the requirement of including a comprehensive set of essential amino acids necessary for parenteral nutrition.