wo ist vitamin d drin — what symptoms are typical?

The question combines two aspects: vitamin D sources and deficiency symptoms. The provided context does not contain direct information on dietary sources of vitamin D or typical deficiency symptoms. It only briefly touches on vitamin D needs and supplementation in children, without specifying sources or symptoms. Generally, vitamin D is primarily synthesized through sunlight exposure; dietary sources include fatty fish (salmon, mackerel), cod liver oil, egg yolks, and fortified foods (e.g., margarine). Deficiency may present as fatigue, bone pain, muscle weakness, mood changes, and increased infection risk. Since the context lacks these specifics, the evidence is rated as unclear. For personalized advice, blood testing and medical consultation are recommended.