Interventions
Backer vCLEAN1-L20 Ultrasonic, Backer
Participants in intervention group were asked to consume a 350 mg propolis tablet (containing 250 mg of Iranian green propolis extract and 100 mg of safe and ineffective combination of microcrystalline cellulose) twice a day (a total of 500 mg Iranian green propolis extract/day) and the control group were asked to intake a same placebo tablet (containing 350 mg of microcrystalline cellulose) twice a day, one tablet before lunch and one tablet before dinner, for 12 weeks. Propolis sample was obtained from honey bee (Apis mellifera) colonies located in Rasht, a region in the north of Iran, in the summer season. First, propolis was ground and extracted with 70% ethanol at a ratio of 1:8. Then, the solution was sonicated by ultrasonic bath (Backer vCLEAN1-L20 Ultrasonic, Backer Co., Tehran, Iran) at 20 kHz and 35 degrees centigrade for 45 min. According to Bankova recommendation for chemical standardization of poplar propolis, total polyphenols content and total flavonoids content in poplar propolis tablets were measured using the spectrophotometric assay (JENWAY 7305, Bibby Scientific Ltd. Stone) based on the Folin–Ciocalteu reducing capacity and aluminum complex formation methods, respectivelyAt the beginning of the study, participants of both groups obtained healthy lifestyle recommendations. Regular use of supplements was reminded to patients through short message service and telephone call weekly and every two weeks, respectively. Also, their compliance to the study was evaluated by counting unused supplements at each visit. A 3-day food record (two weekdays and one weekend day) as the “gold standard” used for dietary intake assessment of each subject. The participants trained by a nutritionist who was unaware to the treatment allocation on how to complete 3-day food records at the beginning, the middle (weeks six), and the end of the intervention. Nutritionist IV software (First Databank Inc., Hearst Corp., San Bruno, CA, USA), which is adapted for Iranian foods was used to calculate the value of nutrition and calorie intake. A 3-day physical activity record (two weekdays and one weekend day) was used to assess physical activity of participants based on metabolic equivalent (MET)-h/day values.