The United States National Library of Medicine says nail abnormalities may indicate health issues elsewhere in the body. Healthy fingernails and to nails are strong, colorless, and smooth. According to Health Daily News, yellowing, crumbling, and white spots are all signs that nails may not be completely healthy. This signs could indicate many type of infection,including bacterial, viral, fungal or yeast. This may also indicate abnormal level of oxygen in the blood, kidney disease, liver disease, thyroid diseases, malnutrition, or a vitamin deficiency. It is advisable to visit a doctor and have a check up should the signs of abnormal fingernails or toe nails are noted so as to find out if there are health conditions that must be addressed.