Since 1984, researchers have debated whether zinc helps people to fight off colds. In that time, five studies have found that it helps, while five others established no such benefit.
A report in the Aug. 15 Annals of Internal Medicine now tilts the balance in favor of zinc, finding that lozenges taken every few hours at the start of a cold slash its average duration nearly in half.
Researchers gave 25 people zinc acetate dihydrate lozenges within 24 hours of the onset of a cold; 23 others received an inert substitute. Both lozenges tasted of peppermint. Neither researchers nor participants were told who was receiving zinc until afterward. Participants took a lozenge every 2 to 3 hours for 4 or 5 days.