Study design
The participants were randomly assigned to consume a balanced diet containing 30 g/day brown milled flaxseed (flaxseed group: n=30) or 30 g/day raw milled rice (control group: n=30) for 12 weeks. Random allocation was performed using blocked randomization method. The study participants, investigators, and outcome assessors were blinded to the type of interventions into which the individuals were allocated. The shape, color, and texture of milled rice were similar to the flaxseed product. For this purpose, we added edible colors to milled rice at the laboratory of pharmacy in Shiraz University of Medical Sciences. Calorie requirement of each subject was estimated using the estimated energy requirement (EER) equation (32). All diets consisted of 55% carbohydrates, 18% proteins, and 27% fats. Also, we provided a portion-size descriptive booklet of common foods for each participant. All the brown flaxseed products were purchased from registered herb provider Maleki Commercial Co. (Iran) and stored in a cool, dark, and dry place. They were milled within a week before delivery to the patients. Participants were asked to mix the powder with their dessert or daily meals (e.g., yogurt, salads, and soup) preferably for lunch. Moreover, participants were advised to maintain their usual physical activity during the intervention.
To assess the participants’ adherence to the intervention, we asked them to bring back any unused flaxseed/placebo at each follow-up visit, so the investigators can estimate their adherence to supplementation during the study period. Participants were excluded if they consumed less than 90% of flaxseed/placebo. Follow-up assessments were done every 4 weeks (on 4th, 8th, and 12th weeks) in which participants were provided with enough supplement for the next four weeks. All measurements including anthropometric indices, blood levels of lipid profiles, leptin, adiponectin as well as dietary intakes and physical activities were performed at the baseline and at the end of the study (week 12).