Signs of a nutritional deficiency can vary widely depending on the specific nutrient lacking in the diet. Common indicators include fatigue, weakness, and reduced immunity. For example, a lack of iron may lead to anemia, resulting in fatigue and weakness, while inadequate vitamin C could manifest as easy bruising and slow wound healing. Other signs may include hair loss, skin problems, and mental health issues like irritability or depression. Monitoring one’s diet and recognizing these signs can lead to timely interventions and better health outcomes.