Hair health can depend on several factors. A lot of the times it has to do with genes and hormones. However, there are some foods you can eat that may help. Some important nutrients include antioxidants, protein and healthy fats like omega-3s, vitamin E, biotin.
Try adding walnuts, berries, cooked sweet potato, tomato, pumpkin seeds, sunflower seeds, avocado, lemons, lentils or other beans, Brazil nut for selenium, antioxidant-rich berries, cabbage, cucumber, red pepper, and celery. Check out this blog for more beautifying foods:
Also...Our Natural Healing Foods book contains a section on Beauty that provides some great recipes!