In many cases (eg, weight loss, osteoarthritis, feline diabetes, feline hyperthyroidism, senior pets with decreased protein metabolism), a protein level above AAFCO recommendations may be desirable.6,7 In contrast, there are medical conditions for which protein levels closer to NRC RA or MR would be helpful (eg, late-stage liver or renal disease).8 Clinicians should understand that for any medical condition, increasing or decreasing protein intake should be relative to the patients current protein intake not relative to NRC or AAFCO values. This underscores the significance of a dietary history.
Of importance, neither NRC nor AAFCO recommend specific nutrient levels for medical or health-related conditions. Recommended amounts of specific nutrients of concern (eg, fat, potassium) for medical conditions are typically set by nutritionists and allied specialists and are based on known specific disease processes. Thus, the recommended dietary concentrations for particular medical conditions will vary among pet food manufacturers and individual specialists.
For example, low-protein therapeutic diets (eg, those marketed for kidney conditions, liver conditions, or uroliths) designed for long-term feeding typically are at or above the NRC crude protein RA9 and use highly digestible (>80%) ingredients with good amino acid profiles (eg, egg, liver, whey). This is done intentionally to ensure that essential amino acid needs are met while offering a lower total nitrogen (ie, crude protein) load to reduce impact on various body organs.