3.Your nails and hair are of the same substance – Both hair & nails are made up of a substance called keratin however in a different form. Hence the food that is good for your hair is also good for your nails. A varied diet rich in vitamins, antioxidant fruits and veggies, protein, and minerals is key for healthy nails and hair. Keratin is a protein, and healthy oils and fats are also needed to keep the skin, hair, and nails moisturized and strong.