The MED-DOPE (MEDiterranean diet-driven Detoxification of OPioid addicted patiEnts) study is a randomized controlled trial that aims to investigate the role of a nutritional intervention based on the principles of Mediterranean diet on craving, which is the primary outcome, and blood redox status of opioid-addicted patients under medication-assisted treatment with buprenorphine and methadone. In detail, the patients of the intervention group will consume three meals per day (i.e., breakfast, lunch and dinner) based on the principles of Mediterranean diet for 90 days. The patients of the control group will follow their normal nutritional habits. Craving as the primary outcome, quality of sleep and biochemical parameters such as blood redox status will be evaluated. It is hypothesized that the applied nutritional intervention will reduce craving, probably through the improvement of blood redox status, of the patients of the intervention group compared to the patients of the control group.

Background: Methadone and buprenorphine are considered as the "gold standard" medication-assisted treatment (MAT) for patients with opioid use disorders (OUDs). Patients who suffer from OUDs usually experience serious health consequences in the psychosocial and the biochemical level. Specifically, they are at 10-fold higher mortality risk than those of the general population. Moreover, there are inconsistencies related to the efficacy of MAT (i.e., methadone and buprenorphine) on retention to treatment and opioid craving, that is a major psychosocial parameter to be improved towards successful rehabilitation. Craving is a central psychosocial component for addiction characterized by a strong urge to use an illicit substance that induces addiction. It appears that although MAT partially normalizes this parameter, patients with OUDs continue to experience craving for opioids leading to drug-seeking behavior and relapse. Furthermore, opioids such as heroine induce oxidative stress, a common toxic biochemical outcome. However, this is the case also for methadone and buprenorphine, although in a lower extent compared to heroine. Therefore, opioid-addiction induced oxidative stress seems to be rather neglected and needs further attention. Oxidative stress is a result of excessive reactive oxygen species generation, which may cause protein and lipid oxidation and oxidative modification of DNA. To that end, the use of plant-derived compounds as auxiliary therapeutic approaches, in combination with methadone and buprenorphine could be a promising approach towards enhancement of the effectiveness of MAT. The biological plausibility for the adoption of such a nutritional practice relies on the fact that plant components namely polyphenols exert potent antioxidant properties against oxidative stress. It has been clearly shown that pomegranate juice is such a physical product. A nutritional approach on the basis of Mediterranean diet could also be considered as an alternative approach towards rehabilitation from addiction to opioids. Indeed, Mediterranean diet has been associated with better health outcomes. Its beneficial effects on human health have largely been attributed to the antioxidant properties of its components, mainly polyphenols.

Objectives: The MED-DOPE (MEDiterranean diet-driven Detoxification of OPioid addicted patiEnts) study aims to investigate the role of a nutritional intervention based on the principles of Mediterranean diet on craving and blood redox status of patients with OUDs under buprenorphine and methadone. This diet scheme is rich in antioxidant compounds that, along with medication (i.e., methadone and buprenorphine), could putatively act beneficially on several health parameters of the patients with OUDs.

Methods: Three meals (i.e., breakfast, lunch and dinner) will be administered daily for 90 days to patients with OUDs under methadone and buprenorphine. In two time points namely Days 1 and 90 the patients will form the heroine craving questionnaire to assess craving, which is the primary outcome of MED-DOPE study. Blood samples will also be collected from the participants in order to measure redox biomarkers (i.e., glutathione concentration, total antioxidant capacity, concentraiton of protein carbonyls, glutathione reductase activity and glutathione peroxidase activity).

Anticipated Outcome: It is hypothesized that the applied nutritional intervention will reduce craving probably through the improvement of blood redox status.

Conclusion: MED-DOPE is a hypothesis-driven and evidence-based project that proposes a nutrition-based solution for craving amelioration in patients with OUDs under MAT, potentially assisting towards their successful rehabilitation and societal reintegration.

Inclusion Criteria:

• Over 20 years of age
• Long-term heroine or other opioid drug use
• Suffering from physical and mental dependence due to chronic opioid use

Exclusion Criteria:

• Serious medical problems, such as infection by human immunodeficiency virus or hepatitis B virus
• Current use of anti-inflammatory medication
• Relapse to other addictive substances (i.e., opioids, methamphetamine, benzodiazepines, cannabis, tetrahydrocannabinol, amphetamine) - To rule out the use of such substances, all participants will undergo weekly urine tests during the three-month period of the trial

Data obtained through this investigation will be provided, upon request respecting GDPR, to qualified researchers and clinicians with related academic interest.