Sugar-free zinc gluconate glycine lozenges (Cold-Eeze) do not adversely affect glucose control in patients with type 1 or type 2 diabetes mellitus.

Several controlled clinical trials have shown that zinc gluconate glycine lozenges can reduce symptom severity and duration of symptoms in patients with the common cold. Over-the-counter zinc lozenges are used commonly by the general population, including people with diabetes. The purpose of this study was to assess the effects of sugar-free Cold-Eeze (The Quigley Corp., Doylestown, PA), a commonly used zinc preparation, on glucose control in patients maintained on stable antidiabetic therapy. Forty-eight patients with either type 1 (n = 3) or type 2 (n = 45) diabetes were randomized in a 3:1 ratio to receive either zinc lozenges (four to six lozenges/day for 10 days) or matching placebo. The primary endpoint was change in serum fructosamine concentration. Secondary endpoints included daily home glucose and fasting blood glucose monitoring (baseline, days 10 and 21). The mean age for all patients was 54 years (range, 25 to 76), with slightly more women (60%). The treatment groups did not differ with respect to age, sex, body mass index, duration of diabetes, baseline hemoglobin A1C level, or fasting plasma glucose level. The patients treated with placebo (n = 13) and zinc (n = 34) had similar fructosamine levels (mean +/- SD) at baseline (318 +/- 90 versus 297 +/- 86 micromol/l, respectively). After 10 days of dosing, both groups showed modest reductions in serum fructosamine (-7 +/- 42 and -9 +/- 90 micromol/l). These changes were not statistically significant. In conclusion, these findings suggest that sugar-free zinc lozenges can be administered safely to patients with diabetes without deleterious effects on glycemic control.