Eat plenty of proteins as a low-protein diet can make the hair brittle and dull. Include complex carbs that prevent hair loss. Hair follicles need iron-rich blood supply so keep up your iron reserves. Add omega-3 fats as they keep your scalp and hair hydrated. Vit C is essential for collagen and Vit A for sebum, that are needed for a healthy scalp. Consume biotin, zinc and selenium rich foods.