Here is the design of a clinical trial:

Official Title: Efficacy of Silymarin in Patients With Non-alcoholic Fatty Liver Disease - The SILIVER Trial: Randomized Clinical Trial

Included conditions:
- Non-Alcoholic Fatty Liver Disease

Study Armgroups:
- {'label': 'Silymarin', 'type': 'ACTIVE_COMPARATOR', 'description': 'Patients will receive 2 capsules containing a total of 700mg of silymarin, 8mg of vitamin E and 50mg of phosphatidylcholine, in addition to the excipient, which should be ingested daily for 12 weeks.', 'interventionNames': ['Dietary Supplement: Silymarin']}
- {'label': 'Placebo', 'type': 'PLACEBO_COMPARATOR', 'description': 'Patients will also receive similarly 2 capsules per day, but without the bioactive principle tested (silymarin). Therefore, the capsules in the control group will contain only 700 mg of maltodextrin, a neutral food component derived from starch, in addition to the excipient and the same amount of vitamin E and phosphatidylcholine to balance the two groups.', 'interventionNames': ['Dietary Supplement: Silymarin']}

Interventions:
- {'type': 'DIETARY_SUPPLEMENT', 'name': 'Silymarin', 'description': 'It is a randomized, double-blind, controlled clinical trial to be performed at outpatient level. The intervention will last 12 weeks and the invited participants will be patients attended at the outpatient clinic of the Edgard Santos Hospital, which will be randomized into two groups: control and intervention. Data on laboratory and clinical markers, imaging, nutritional and dietary assessment will be collected at the beginning and end of the trial for comparison purposes.', 'armGroupLabels': ['Placebo', 'Silymarin']}

Primary Outcomes:
- {'measure': 'Absence or change in NAFLD degree', 'description': 'Absence or change in NAFLD degree, assessed by the value of the difference in the attenuation coefficient between liver and spleen obtained by computed tomography of the upper abdomen performed at the beginning and at the end of the study.', 'timeFrame': 'They will be dosed at baseline and after 12 weeks of intervention.'}

Please estimate the sample size based on the assumption: 
A significance level of 0.05 and a power of 80% were adopted.
Sample Size {14}
        The sample size was determined through an accuracy analysis of the primary outcome. A significance level of 0.05 and a power of 80% were adopted, which resulted in a minimum sample size of approximately 132 participants.