A 62-year-old man recently showed up to a hospital in Glasgow, complaining of weakness and tingling in his legs. The sensations had become so severe during the prior six months that he had to resort to a wheelchair to get around and had great trouble leaving the house. Although he'd had some trouble with narrowed arteries, and was a lifelong smoker, the cause of these strange and alarming symptoms wasn't immediately obvious.
Further investigation revealed the man had slight degeneration of six vertebrae in his neck, and that he'd lost more than a dozen pounds. Testing revealed slightly elevated levels of zinc and low levels of copper. His doctors, led by Liam Carroll, at Queen Elizabeth University Hospital, ascertained that every week for years the man had been using two to four tubes of dental fixative—which contain high levels of zinc—to keep his ill-fitting dentures in his mouth.
The physicians concluded that the man was suffering from copper deficiency myelopathy, a malfunction of the spinal cord caused by a lack of the mineral, as explained in a paper in BMJ Case Reports, of which Carroll is the lead author. Ingesting too much zinc, the doctors explain, interferes with the absorption of copper, a trace element that is necessary for the production and function of several proteins vital to the brain and bone marrow.
The treatment for this condition is copper supplements and ceasing excess zinc. The doctors advised the man to get new dentures, and he quit using the zinc-containing fixative. The man, who had been a mechanic, also began a course of treatment with physical therapists, although he remains largely a wheelchair user.
If not quickly recognized and treated, copper deficiency, or hypocuremia, can cause irreversible neurological problems, as in this case. The man had felt tingling for about six months prior to showing up at the hospital, and although the treatment reversed the decline, and the tingling disappeared, the degeneration of the spine may be permanent.
Copper deficiency is rare, but becoming more common, according to a 2014 review in the Annals of the New York Academy of Sciences. Copper (and other minerals) are absorbed in the upper intestinal tract, and bariatric surgery for weight loss has been implicated in copper deficiencies because it shrinks the areas that can absorb these substances. As these procedures are becoming more common, the risk for copper deficiency grows. Cases of zinc-induced copper deficiency are unusual, the review notes, but are also on the rise. So if you find yourself with some ill-fitting dentures, go easy on the dental fixative.
