This exploratory study was designed to assess the effectiveness of a lignan-rich extract of flaxseed hulls (LinumLife EXTRA(®)) in alleviating symptoms in subjects with benign prostatic hyperplasia (BPH) compared with placebo. Two dosages of extract were compared against placebo in a double-blinded, randomized, parallel, multicenter study. Newly diagnosed cases of BPH in patients aged 45-75 years with an American Urological Association Symptom Index (AUASI) score of ≥13 were included. Study treatment consisted of 500 or 1000 mg of extract containing 100 mg (low-dose active [LDA] group, n=26) or 200 mg (high-dose active [HDA] group, n=26) of secoisolariciresinol diglucoside (SDG), respectively. The placebo (P) group (n=28) received matching maltodextrin capsules. Sixty subjects (LDA [n=19], HDA [n=20], and P [n=21]) completed the study as per the protocol requirements. Change in the AUASI score within a period of 8 weeks, from baseline to end of treatment, was assessed. Significant improvement of obstructive symptoms and management of irritable BPH symptoms was achieved in all groups after treatment. Due to a strong placebo effect, there was no statistical difference between the groups that were treated with flaxseed hull extract as compared with the placebo group. Treatment with flaxseed hull extract did not lead to adverse effects compared with placebo. Supplementation with flaxseed hull extract was found to be safe and well-tolerated and may have improved the quality of life of individuals with BPH. The significant placebo effect as well as the number of subjects per treatment group and the relative short duration of the study may explain the lack of statistical significance between groups.
Keywords: AUASI; clinical trial; secoisolariciresinol diglucoside (SDG); supplement.