WEST PALM BEACH, Fla., April 2 (UPI) -- In the largest study of its kind, doctors said Monday that use of the supplement zinc sulfate failed to restore normal taste to patients who had radiation for head and neck cancer.
"The results of this study were disappointing in that we hoped that zinc sulfate would help patients maintain their taste based on prior pilot data," said Michele Halyard, a radiation oncologist at the Mayo Clinic Scottsdale in Arizona.
"Frequently, patients who undergo radiation for head and neck cancers that impact the oral cavity suffer some alteration of taste," Thomas Eichler, medical director of the Thomas Johns Cancer Center, Richmond, Va., told United Press International.
"We were very hopeful this study would prove successful," he said, "because the taste alteration doesn't mean that food doesn't taste good, it often means food tastes bad. It is unfortunate this study proved negative because we have very little to treat these patients."
He suggested that loss of taste sensation or having food that tastes bad can slow a patient's recovery from the multiple effects of radiation, chemotherapy and surgery. Eichler said losing taste sensation can lead to a significant change in eating habits, causing some patients to avoid certain unappealing foods, sometimes leading to additional weight loss at a time when good nutrition is critical.
Halyard said that previous academic studies in cancer and non-cancer settings had suggested that the use of zinc sulfate could help patients regain their sense of taste more quickly after radiation therapy. But the phase three, multi-institutional, double-blind, placebo-controlled study found that giving patients a zinc sulfate vitamin supplement had little to no effect on the sense of taste for the patients in the study, she said.
In the clinical trial, reported in the current issue of the International Journal for Radiation Oncology*Biology*Physics, the journal of the American Society for Therapeutic Radiology and Oncology, Halyard and associates enrolled 173 patients who had undergone treatment for head and neck cancer with traditional radiation therapy. Four patients received no treatment, so researchers were left to evaluated 84 patients who received zinc, and 85 who were given placebo.
Patients were divided into two groups, one group treated with zinc, the other with sham medication called placebo. Both groups experienced similar degrees of taste alteration, but doctors reported that there was no significant difference in taste recovery between the groups.
About 6 percent of the zinc-treated group achieved complete taste recovery, compared to 18 percent in the placebo group. "This study is the largest ever reported to date to evaluate zinc sulfate in the treatment or prevention of taste alteration for patients receiving radiation therapy for head and neck cancer," Halyard said.
Although the trial failed to show zinc is helpful, "we can further explore other promising treatments to help patients maintain their quality of life during and after treatment. The search goes on," she told UPI.
Eichler, who was not part of the study, said that when radiation with or without chemotherapy is used to treat patients, the taste buds are frequently affected. For these patients, usual food flavors taste bland or different, with a few patients losing the sensation of taste altogether.
He said it is possible that zinc sulfate might help some individuals.
Halyard said that, at the dose used in the study -- 45 milligrams of zinc sulfate three times a day -- there did not appear to be any difference in adverse side effects from the placebo.
