A single serving of oyster mushrooms (Pleurotus ostreatus) helped older adults maintain a steadier mood and reduce inflammation throughout the day. While the control meal led to lower positive mood and higher mental fatigue, meals containing oyster mushrooms prevented that slump. Blood tests also showed lower inflammatory markers after eating oyster mushrooms, suggesting a gentle anti-inflammatory effect. Cognitive results were mixed, but overall the mushroom-rich meals helped people feel better and stay more mentally balanced over the test day.