Materials and Methods
This was a double-blind randomized controlled clinical trial. Fifty overweight diabetic females were recruited from the outpatient Endocrine Clinic of Sina Hospital in Tabriz City from December 2010 to March 2011 with written consent. Study inclusion criteria were patients who had been diagnosed with type 2 diabetes within the previous 1 year, aged 30-65 years, BMI 25-30, taken glucose-lowering medications for type 2 diabetes but without insulin injection. Exclusion criteria included consuming trace element and antioxidants supplements in the previous 6 months, pregnancy and lactation, having acute renal disease, endocrine dysfunction and allergy.
The study protocol was approved by the Ethics Committee of Tabriz University of Medical Sciences and was registered in the Iranian Registry of Clinical Trials website (IRCT201011131197N5).
A computer-generated random sequence was kept in a remote secure location and administered by an independent third party who was not involved with the clinical conduct of study until all study data were collected and verified. Patients and those involved in enrolling participants, administering interventions and assessing outcomes were blind to group assignments. The patients randomly were assigned into the supplemented group (n=25), receiving royal jelly soft gel (each soft gel include 1000 mg lyophilized royal jelly providing 1 gram fresh royal jelly) once a day after breakfast or a control group (n=25) receiving one placebo soft gel for 8 weeks. The participants were asked to keep their usual dietary intake, physical activity and medication during the study period unchanged. Patients were monitored weakly for any side-effects of royal jelly supplementation. A total of 5 patients did not complete the study for reasons that included: 3 patients due to poor compliance with study protocols, 1 patient due to gastrointestinal disturbances, and 1 patient due to personal reasons.