Effect of Fruit Smoothie Supplementation on Psychological Distress Among People Receiving Opioid Agonist Therapy

Participants randomised to the intervention arm will receive a 250 ml fruit smoothie as diet supplement for 20 weeks in addition to the regular OAT clinic follow-up. The fruit smoothies will be marketed products including combinations of the following fruits: apple, pineapple, mango, bananas, orange, blueberries, passion fruit, coconut, lime, and blackcurrant. The participants will receive a mixture of different smoothie types with the option of removing alternatives based on preferences. Fruit smoothie products will come in plastic bottles and will be delivered directly to the participants on a weekly basis. Each participant will receive a total of seven smoothie bottles per week with an oral agreement with each participant to consume one of these per day. Delivery of fruit smoothie will generally be given in parallel with delivery of OAT medication.