Zinc deficiency does not cause nails to turn white, according to Dr. Andrew Weil. Liver disease can cause fingernails to turn completely white. White spots on fingernails, called leukonychia, typically develop as a result of a minor injury, such as banging or knocking the fingers, but can also occur due to an allergic reaction to nail polish or a mild infection.
Symptoms of zinc deficiency include patchy hair loss, an impaired sense of taste and smell, skin rashes, and loss of appetite, as reported by Merck Manuals. Children who do not consume enough zinc may experience slowed growth, and adult males deficient in zinc may developed reduced sperm counts. Zinc deficiency can also impair the body's immune system and cause wounds to heal more slowly. Infants born to women deficient in zinc are at increased risk for birth defects.
Adult men need 11 milligrams of zinc per day, and adult women need 8 milligrams of zinc per day, according to the National Institutes of Health. Pregnant and breast-feeding women require additional zinc. Oysters, red meat, poultry, seafood and fortified breakfast cereals are good sources of zinc. Whole grains, nuts, dairy products and bean also contain zinc.
Too much zinc can be harmful, states the National Institutes of Health. Signs of excessive zinc consumption include headaches, diarrhea, stomach cramps, nausea and vomiting.