The association between animal‑based and plant‑based protein intake with sleep quality, mood, anxiety, depression and stress among elderly: a cross-sectional study

Higher total protein intake was associated with some improvements in sleep and mood, but findings were inconsistent across outcomes. Animal protein appeared beneficial for mood and depression, whereas both plant and animal protein were linked to poorer sleep quality. These mixed results highlight the complexity of diet-mental health relationships and the need for cautious interpretation.