Fingernails that are very soft or flake apart easily could indicate a lack of the protein keratin, which is typically caused by a sudden nutritional change that deprives the body of essential vitamins and nutrients. Ridges on nails may indicate malnourishment or a lack of iron, says Everyday Health.
Fingernail disorders are defined as problems with the texture, shape, thickness or color of the nails. Just as an examination of the skin can tell a lot about an individual's general health, so can a close examination of fingernails, says MedlinePlus.
Certain abnormalities are clear indicators of a nutritional deficiency. Thin fingernails that curve inward and have raised ridges are referred to as koilonychia, which is a warning sign of anemia, states MedlinePlus.
These types of fingernail disorders are generally resolved easily. Koilonychia can be cleared up by eating an iron-rich diet, and problems and blemishes caused by a keratin insufficiency are treated by following a diet rich in protein. Daily supplements of biotin, a B vitamin, should also help, according to Everyday Health.