A nurse is educating a patient on increasing protein intake after surgery. The patient is vegetarian but eats animal products, just not the animal itself. Which of the following foods would provide the best source of protein for healing after surgery?

Choice A reason: The 10-20% range is too low for protein intake in adults. Protein should contribute 20-35% of calories to meet amino acid needs for muscle maintenance, enzyme production, and immune function, as lower intakes may lead to deficiencies in active individuals.

Choice B reason: The 45-65% range corresponds to carbohydrate recommendations, not protein. Proteins at this level would exceed metabolic needs, potentially straining kidneys due to excess nitrogen excretion, and are not aligned with standard dietary guidelines for adults.

Choice C reason: The Dietary Reference Intake recommends proteins provide 20-35% of daily calories for adults, balancing amino acid needs for tissue repair, enzyme synthesis, and immune function. This range supports metabolic demands without overloading the kidneys with excess nitrogen waste.

Choice D reason: The 35-45% range overestimates protein needs for most adults. Excess protein intake beyond 35% may lead to increased nitrogen excretion, potentially stressing kidneys, and is not typically required unless under extreme conditions like intense athletic training.

Reasoning:

Choice A reason: Childbirth is a physiological process, not a direct function of protein. Proteins support related processes like tissue repair (e.g., during postpartum recovery), but childbirth itself is driven by hormonal and muscular mechanisms, not a primary protein function, making this an incorrect choice.

Choice B reason: Proteins are critical for the body’s defense system, forming antibodies and immune cells like lymphocytes. These proteins, such as immunoglobulins, neutralize pathogens, supporting immune function. Approximately 10-15% of dietary protein supports immune responses, making this a key function in infection resistance and recovery.

Choice C reason: Proteins, like albumin, maintain water balance by regulating oncotic pressure in blood plasma, preventing fluid leakage into tissues (edema). Low protein intake can disrupt this balance, leading to swelling, as proteins are crucially needed to retain fluid within blood vessels, making this a correct function.

Choice D reason: Proteins are essential for tissue building, providing amino acids for muscle, skin, and organ synthesis. About 1.0-1.5 grams/kg body weight daily supports collagen formation, cell repair, and growth, particularly during recovery or development, making this a fundamental protein function in the body.

Choice E reason: Proteins facilitate metabolism as enzymes and hormones, catalyzing biochemical reactions and regulating processes like glucose uptake (e.g., insulin). Approximately 20% of dietary protein supports enzymatic functions, ensuring energy production and nutrient metabolism, making this a critical role of proteins in the body.