Four groups (group sizes not stated) of male rats were examined respectively for 26 days or for 52 days: 1) control group, 2) exposure group, 3) exposure group and administration of Ganoderma lucidum (20 mg/kg body weight, administered orally) and 4) exposure group and administration of melatonin (10 mg/kg body weight, injected intraperitoneally on a daily basis).
Ganoderma lucidum (also called "lingzhi mushroom" or "reishi mushroom") is a mushroom which is used as an alternative medicine.
In rats exposed for 52 days (group 2) (also for 26 days? contradictory statements), the level of zinc was significantly decreased compared to the control group (group 1). Rats exposed for 52 days and given melatonin (group 4) (also group 3 with Ganoderma lucidum? contradictory statements) showed significantly increased concentrations of zinc (and strontium? contradictory statements) in the teeth (similar to the control group) when compared to the exposure group without additives (group 2).
The authors conclude that extremely low frequency magnetic and electric fields could influence the content of trace elements in rat teeth and the administration of melatonin (and Ganoderma lucidum?) could prevent these alterations.