What vitamins andor foods are best to encourage strong and healthy hair growth?

A dear friend of mine has noticed her hair thinning. She is over thirty but younger than fourty. She has had her hair chemically treated however has now stopped - with the occasional supermarket rinse. She has noticed that although she has ';baby'; hair re-growth her hair is not as thick as it once was and is concerned she will loose it all! She is open to any suggestions for changing diet, vitamin suppliments,etc but doesn't know which to have - nor do i??) Have any suggestions to help her?What vitamins andor foods are best to encourage strong and healthy hair growth?
Add hemp seed oil to your diet help. Hemp seed oil contains one of the very important nutrient we need everyday. Hemp seed oil in itself contains the ideal 3:1 ratio of Omega-3 and Omega-6 essential fatty acids. This oil improves hair growth soften your skin, boosts the immune system, reduces blood clots and increases energy. Also, I would avoid the shampoo and conditioner that contain chemicals that cause many health problems. They may be make your hair look and feel good but not necessary good for your hair.What vitamins andor foods are best to encourage strong and healthy hair growth?
BIOTIN IS THE BEST. IT IS SHAMPOO AND CONDITIONER BUT YOU CAN ALSO BUY THE TABLETS AT A LOCAL HERBAL PLACE. WE HAVE LASSENS HERE IN CALIFORNIA.
prenatal vitamins could help. i'm not TTC, nor do i want kids, but i do take a prenatal vitamin as a daily, and it makes my hair and nails grow like crazy!