Your fingernails can be a greater indication of your overall health than you may think. Although they serve a cosmetic function for most, nails are a living part of your body and if you're not healthy, your nails won't be either. Changes in the fingernails can indicate everything from psoriasis to heart disease and several nail conditions can indicate malnutrition or certain nutrient deficiencies.
Check for small depressions across your fingernails. These are called Beau's lines, and they can be a symptom of malnutrition. They can also occur after an illness or an injury to your nail and can be a symptom of uncontrolled diabetes, according to the National Institutes of Health.
Iron deficiency anemia also manifests itself in the nails via a condition called koilonychia, or spoon nails. Koilonychia is an abnormal fingernail shape marked by thin nails with an inward curve and raised ridges, according to the NIH. If you experience koilonychia, increase your iron intake.
If your nails look mostly opaque but have a dark band at the tips, you may have a condition called Terry's nails. This nail condition can be a sign of malnutrition, but is also caused by aging, congestive heart failure, diabetes or liver disease, according to the NHS.UK website.