As with all things beauty, you put good in, you get good out. Want strong nails, glowing skin, and thick, shiny hair? Put down the chocolate chip cookie, and load your plate with a rainbow of veggies. Unfortunately, certain nutritional shortcomings are impossible to avoid, thanks to busy schedules and hectic lives. But since healthy hair starts from the inside out (deep conditioning can only do so much), the beauty industry has developed supplements that will pump your body with all of the vitamins, minerals, and fatty acids needed to give you a gorgeous mane.