What is the protein intake recommendation for critically ill older adults?

• A. 0.8 g/kg/day
• B. 1.7-2.2 g/kg/day
• C. 2.5-3.0 g/kg/day
• D. 3.0-4.0 g/kg/day

Answer: (B)

In critical illness, the body is highly catabolic and protein breakdown increases to supply amino acids for immune function, tissue repair, and wound healing. In older adults, there is also anabolic resistance, meaning the muscles don’t respond as effectively to protein, so more protein is needed to maintain lean mass and support recovery. Because of these factors, protein needs are raised above the usual amount for healthy adults, but staying within a range that avoids excessive nitrogen burden is important.

The recommended intake of about 1.7–2.2 g of protein per kilogram of body weight per day reflects this balance: it provides enough amino acids to support immune function and healing while staying within a level that is generally safe and practical for critically ill older adults. It’s also aligned with guidelines that recognize the higher needs in critical illness and older age, without venturing into inappropriately high amounts that could stress the kidneys, especially if renal function is impaired.

Choosing a lower intake, such as the general 0.8 g/kg/day, would likely be insufficient to meet the heightened demands of critical illness and aging. Exceedingly high intakes in the 2.5–4.0 g/kg/day range are not typically supported by evidence and could increase the nitrogen load without proven additional benefit, with potential risk in those with compromised kidney function.