The makers of Super PoliGrip have apparently caved to consumer pressure, adding a zinc-related warning to packages of the popular denture cream. The move by GlaxoSmithKline (GSK) comes after dozens of lawsuits and a prominent medical article outlined the danger of zinc poisoning resulting from overuse of denture adhesives.

Zinc, a type of metal, is abundant in the earth's crust and is one of the most commonly found elements on the planet. Zinc is an essential human nutrient, and some amount is present in all foods. Indeed, a diet deficient in zinc can ultimately lead to nausea, an inhibited sense of taste, and decreased immune function.

That said, getting too much zinc is no picnic either. Excessive zinc intake over a long period of time can ultimately lead to anemia, pancreatic diseases, and decreased levels of HDL, also known as the "good cholesterol."

Boxes of Super PoliGrip now come with an insert informing consumers of the product's zinc content and warning generally that excessive zinc intake can lead to "serious health effects." The insert advises users who take zinc supplements to talk with their doctor. The insert warns that consumers should not use Super PoliGrip more than once a day, and that a regular-sized tube should last several weeks.

Both Super PoliGrip and Fixodent, another well-known adhesive, have been linked to cases of zinc poisoning. A disturbing 2008 article published in Neurology, a monthly medical journal, described four patients whose use of denture cream caused neuropathy, a nerve disorder affecting the central nervous system. The patients, who all used about two tubes of adhesive every week, suffered copper deficiency, which ultimately caused neurological problems. Neuropathy can cause distinct motor and sensory disturbances; the patients detailed in the article suffered from weakness in the limbs, poor balance, and urinary incontinence, among other things. At least one was confined to a wheelchair.

The U.S. Drug Watchdog, a consumer advocacy group, has taken the lead in warning consumers of the potentially fatal effects of denture-induced zinc poisoning. The group recently warned that inadequately labeled denture creams have the potential to create "the worst case of zinc poisoning in U.S. history." The Watchdog notes that the Food & Drug Administration (FDA) does not require companies to disclose the real danger of zinc poisoning posed by denture creams.

GSK, the manufacturer of Super PoliGrip, has already been hit with a number of lawsuits relating to denture-induced zinc poisoning. And they aren't alone; other denture cream manufacturers have also been served with complaints, most notably Procter & Gamble, which makes Fixodent. About thirty lawsuits against those two manufacturers alone have been consolidated and are being handled by Judge Cecilia Altonaga of the United States District Court for the Southern District of Florida.

Denture cream users should be on the lookout for signs of zinc poisoning. These symptoms include burning sensations, abnormal heartbeat, a metallic taste in the mouth, constipation or urine blockage, tingling in the extremities, poor balance, and slowed movements. Denture users who think they are experiencing zinc poisoning should immediately seek medical attention. The National Poison Control Center (800-222-1222) also has experts on hand who can provide instructions.