• Vitamin A – This vitamin is an antioxidant that helps produce healthy sebum in the scalp. Food sources: spinach, broccoli, cabbage, carrots, apricots and peaches.  
• Vitamin C – It is an antioxidant that helps maintain skin & hair health. Food sources: Citrus fruits, strawberries, kiwi, cantaloupe, pineapple, tomatoes, green peppers, potatoes and dark green vegetables.
• Vitamin E – This vitamin is an antioxidant that enhances scalp circulation. Food sources: Cold-pressed vegetable oils, wheat germ oil, raw seeds and nuts, dried beans, and leafy green vegetables.
• Biotin – This vitamin produces keratin that prevents hair loss and hair graying. Food sources: Almonds, peanut butter, banana, papaya, carrots, avocado, tomato sauce, and sweet potato.
• Inositol – This vitamin keeps hair follicles healthy at the cellular level. Food sources: Whole grains, brewer’s yeast, citrus fruits (oranges), nuts, and cantaloupe.
• Niacin (Vitamin B3) – This vitamin allows scalp blood circulation. Food sources: Peanut butter and lentils
• Pantothenic Acid (Vitamin B5) – This prevents graying and hair loss. Food sources: Celery, cucumber, bell pepper, corn, mushrooms, avocado, and cauliflower.
• Vitamin B6 – It prevents hair loss and helps create melanin that gives hair its color. Food sources: Spinach, broccoli, Brussels sprouts, kale, squash, banana, eggplant, onion, grapes, and ginger root.
• Vitamin B12 – It prevents hair loss. Food sources: Dulse.

(Source: http://www.worldofhair.com/geo/vitamins.htm)