The tree that produces the arbutus berry, the strawberry tree, scientific name Arbutus unedo L., belongs to the family of Ericaceae. It exists in almost all of Southern Europe in arid and siliceous lands, in woods and forests and is very common in Portugal.

Known for its use in the production of liqueurs and brandy, the arbutus berry is a fruit that can be consumed in nature or incorporated in the preparation of other foods. Arbutus berry has been attributed some properties beneficial to health given its low caloric value and its high content of vitamin C and flavonoids, which is why it is considered a good source of antioxidants.

Arbutus has a high carbohydrate content (70-80% dry weight) with a relevant fiber fraction (10-30%), constituting an interesting source of vegetable protein (1-9%) and lipids (2-3%). Given this interesting nutritional composition, the hypothesis is that a daily consumption of this fruit can have an impact in health outcomes such as microbiota modulation and an improvement of metabolic parameters.

The main objective of this clinical trial is to evaluate the effect of including a daily consumption of arbutus berry on the composition and diversity of the intestinal microbiota. It is also intended to evaluate metabolic parameters to determine the impact of this intervention.

Participants will consume 50g or 200g of arbutus berry daily for 4 weeks. This study aims to provide scientific evidence regarding the impact of arbutus berry consumption on intestinal microbiota and general health improvements.

Inclusion Criteria:

• Caucasian.
• Age between 18 and 50 years.
• Filling informed consent.
• Body mass index (BMI) between 18,5 kg/m2 and 25 kg/m2.

Exclusion Criteria:

• Arbutus berry sensibility.
• Arbutus berry daily consumption in the month before the study begin.
• Having taken antibiotics within the 6 months prior to beginning the study.
• Use of pro/prebiotics or fiber as a dietary supplement or any food/molecule that modifies intestinal transit time 6 weeks before recruitment.
• Use of laxative 6 weeks before recruitment.
• Specific nutritional therapy (e.g. high protein).
• Excessive alcohol consumption.
• Smoking.
• Diagnosis of gastrointestinal pathology, hormonal or thyroid pathology, autoimmune diseases, chronic use of corticosteroids, psychiatric disease or Diabetes Mellitus.
• Use of proton pump inhibitors, antidiabetic drugs, insulin, or statins.
• Pregnant or breastfeeding.
• Participation in another clinical trial within the last 3 months.