Study participants
The present study was a randomized, double-blind, placebo-controlled clinical trial in which 60 overweight or obese women aged 25 to 50 years, with a body mass index (BMI) 25-35 kg/m2 and regular menstrual cycles participated. Participants were excluded if they met one or more of the following criteria: 1) any chronic disease such as cardiovascular, renal, liver and infectious diseases as well as cancer, diabetes mellitus, and thyroid disorders, 2) with history of allergy to flaxseed, 3) being pregnant or lactating, 4) taking any medications that could affect lipid metabolism (Steroids, anti-hyperglycemic agents, statins), 5) taking supplements including multivitamins and minerals and also, herbal preparations, and 6) history of smoking or alcohol and drug abuse. The minimum sample size estimated for each group was 25 at a power (1–β) of 80% and α₌0.05 for a two-arm parallel study with two-tailed testing to detect a difference of 4 ng/mL in serum adiponectin concentration with a standard deviation of 5 ng/mL, obtained from a previous study (31). Assuming a 10% drop out, a total number of 60 participants was considered for this study. The study protocol, risks, and benefits were clarified
to the participants, and they signed a written informed consent at the time of enrollment. This study was approved by the Ethics Committee of Shiraz University of Medical Sciences, Shiraz, Iran (registration No. IR.SUMS.REC.1395.22) and was registered at Iranian Registry of Clinical Trials website (IRCT2016050327733N1).