Keratin is actually an insoluble structural protein found in skin, hair and nails and therefore what can be defined as a keratin-rich food would be food made from the skin of an animal such as pork rinds. However, humans do not really need keratin supplementation as it is already being naturally produced by skin cells. Other than edible animal skins, there is no other food source that can be described as rich in keratin. A healthy and balanced diet rich in protein and vitamins A and C will ensure that the body can form adequate amounts of keratin for healthy skin, hair and nails.
Keratin is a type of protein which serves as a building block of some living tissues like skin, hairs and nails. So eating foods which are rich in certain proteins can increase keratin levels which improve growth, health and appearance of hairs and nails. Mainly iron rich protein (meat, green vegetables-beans, nuts and whole grain, dairy products-milk, cheese, yogurt); B-Vitamins (cereals, banana, lentils); Zinc rich food (peanut butter, oysters, pork); Vitamin C rich food (citrus fruits-oranges, grapefruit, broccoli, kale) and folate are good source of Keratin.