Zinc is a trace mineral that is necessary for proper functioning of the body. This mineral also aids the body’s immune system by helping fight infection and assisting with wound healing. It is possible to get enough zinc from commonly eaten foods, including oysters, beef, beans and peanuts. Taking supplemental zinc helps prevent the virus that causes the common cold, called rhinovirus, from multiplying and may shorten the duration of a cold, according to the Mayo Clinic. Taking too much zinc can cause harmful side effects.

Zinc Dosages

The recommended daily allowance for zinc in males over the age of 14 is 11 milligrams per day. Women who are not pregnant or lactating need 8 milligrams per day. Pregnant and lactating women need 11 to 12 milligrams daily. Adults should keep supplemental zinc intake below 40 milligrams daily, unless directed by a physician to take more, according to MedlinePlus.

Overdose Symptoms

Many abdominal pains and problems may occur if a person takes too much zinc. Symptoms may include diarrhea, nausea, vomiting and stomach pain. Some people may experience irritation in the mouth and throat. Flu-like symptoms such as fever, chills and coughing may also occur. Jaundice, or a yellowing of the eyes and skin, may occur if the zinc damages the liver.

Zinc Poisoning

In addition to supplements, cold medications and food, items such as paint, dye and diaper ointments can contain zinc. Ingesting these items can cause zinc poisoning. Taking excessive amounts of zinc supplements can also lead to poisoning symptoms. Symptoms of zinc overdose are usually early warning signs of zinc poisoning. Additional symptoms that may occur with zinc poisoning include low blood pressure, no urine production, shortness of breath, convulsions and shock.

Nasal Spray Side Effects

Some nasal spray cold medications contain zinc. These over-the-counter medications have specific concerns that can occur with normal use and with zinc levels in normal limits. People using zinc nasal sprays and nasal gel may lose the sense of smell after administering the medication. For some, this loss can continue well after discontinuing the medication and may become permanent.

Considerations