The goal of this clinical trial is to learn whether drinking a daily serving of gazpacho can improve semen quality in men with reduced sperm quality. The study will also examine how this dietary intervention affects oxidative stress and whether it is well tolerated.

The main questions this study aims to answer are:

• Does daily consumption of gazpacho improve semen quality in men with altered semen parameters?
• Does this dietary intervention affect levels of oxidative stress in semen?
• Is daily gazpacho intake feasible and well tolerated as part of a Mediterranean diet?

Researchers will compare a Mediterranean diet plus daily gazpacho intake with a Mediterranean diet alone to determine whether adding gazpacho provides additional benefits for male reproductive health.

Participants will:

• Follow a standardized Mediterranean diet for 12 weeks
• Drink 330 mL of gazpacho every day or follow the diet without gazpacho
• Provide semen samples at the start of the study and after 12 weeks
• Complete a short diary to record adherence to the dietary intervention
• Be followed for up to 18 months to record reproductive outcomes

Detailed Description

This is a single-center, prospective, randomized, open-label, parallel-group study conducted at GINEFIV (IVIRMA Madrid). Eligible participants are men aged 18-45 years with an andrological profile that includes altered semen parameters such as oligozoospermia with or without associated asthenozoospermia and/or teratozoospermia (O±A±T). Participants will be randomized in a 1:1 ratio to a control group following a standardized Mediterranean diet or an intervention group following the same diet with the addition of 330 mL per day of commercially available gazpacho.

The intervention period lasts 12 weeks. Participants in the intervention group will consume gazpacho once daily with a main meal. Two production batches of the product will be analyzed to determine lycopene, vitamin C, and vitamin E content. Adherence to the intervention will be evaluated using a self-administered compliance diary and scheduled follow-up phone calls.

Semen samples will be collected at baseline and at the end of the intervention period. Semen analysis will be performed according to World Health Organization (WHO) 2021 guidelines. Seminal oxidative stress will be assessed using the OxiSperm II test and its Research Use Only (RUO) digital application, which will not be used for clinical decision-making.

The primary objective of the study is to evaluate changes in semen quality following the intervention. Secondary objectives include the assessment of seminal oxidative stress, adherence to the dietary intervention, safety and tolerability, and reproductive outcomes collected during post-intervention follow-up.

Participants will be followed for 18 months after completion of the intervention to record reproductive outcomes. The total study duration is estimated at 54 months, including recruitment, intervention, follow-up, and data analysis periods.

Inclusion Criteria:

• Men aged 18 to 45 years
• Andrological profile including altered semen parameters such as oligozoospermia, asthenozoospermia and/or teratozoospermia (O±A±T)
• No clinical indication for sperm DNA fragmentation testing or advanced sperm selection techniques
• Willingness and ability to comply with the study protocol, including adherence to a standardized Mediterranean diet
• Signed and dated written informed consent form

Exclusion Criteria:

• Use of antioxidant supplements during the three months prior to study start.
• Active smokers or men who have stopped smoking within the last three months.
• Diagnosis of azoospermia, leucocytospermia or necrozoospermia.
• Presence of severe systemic diseases or chronic conditions that could interfere with semen quality or adherence to the study.
• Known allergy or intolerance to any ingredient of the gazpacho used in the study.
• Any medical, psychological or social condition that, in the investigator's judgement, could compromise the subject's ability to participate fully or comply with the protocol requirements.
• Simultaneous participation in another clinical study.

Individual participant data will not be shared with external researchers. The study involves sensitive reproductive health data, and there is no predefined plan for public data sharing. Data may be processed by authorized technical partners for analytical purposes under confidentiality agreements, in compliance with applicable data protection regulations.

This is an open-label study. Due to the nature of the dietary intervention, masking of participants and care providers is not feasible. Laboratory personnel performing semen analysis and oxidative stress assessments are not involved in the allocation process and are blinded to group assignment.