Condition category
Not Applicable
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Background and study aims
Human semen quality has declined in industrialized nations, with pollution, smoking, and trends toward a Western-style diet as possible causes. Although the importance of diet to human reproductive success is clear, existing dietary recommendations primarily focus on women’s reproductive health with less attention given to men. Because nuts have a considerable amount of several nutrients that are involved in male fertility, we believe that tree nut consumption added to a Western-style diet would improve semen quality and functionality. The aim of this study is to evaluate the effect of eating tree nuts on semen quality.

Who can participate?
Healthy men aged between 18 and 35

What does the study involve?
Participants are randomly allocated to one of two groups. One group continues to consume their usual diet supplemented with 60 g per day of a mixture of raw nuts. The other group continues to consume their usual diet, avoiding consumption of nuts. Blood and sperm samples are collected at the start of the study and after 14 weeks to assess sperm quality.

What are the possible benefits and risks of participating?
Participation in the study may help the participants to better understand their health. The information obtained may benefit other patients in the future and contribute to a better understanding of the effect of nut consumption on male fertility. There are no health risks involved in this study. The extraction of the blood sample can cause a burning sensation at the point where the needle is inserted and can cause a small bruise which disappears in a few days. More rarely it can cause transient dizziness.

Where is the study run from?
1. Universitat Autònoma de Barcelona (Spain)
2. Universitat Rovira i Virgili (Spain)

When is the study starting and how long is it expected to run for?
September 2015 to August 2017

Who is funding the study?
INC International Nut and Dried Fruit Council Foundation (Spain)

Who is the main contact?
Dr Mònica Bulló Bonet

Trial website

Contact information



Primary contact

Dr Mònica Bulló Bonet


Contact details

C/Sant Llorenç
+34 (0)977 75 93 13

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Effect of nut consumption on semen quality and functionality in a cohort of healthy males



Study hypothesis

Because nuts have a considerable amount of several nutrients that have been implicated in the modulation of several mechanism implicated in male fertility, we hypothesize that tree nut consumption added to a Western-style diet would beneficially affect semen quality and functionality.

Ethics approval

Comitè d'Ètica d'Investigació Clínica (Hospital Universitari Sant Joan de Reus), 29/10/2015, Ref. CEIC: 15-10-29/10aclaassN1

Study design

Randomized 14-week parallel two-group dietary intervention trial with single-blind masking of outcome assessors

Primary study design


Secondary study design

Randomised parallel trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use contact details to request a participant information sheet


Semen quality and functionality


Participants will be randomly assigned to one of two intervention groups for 14 weeks:
1. Continue to consume their usual diet supplemented with 60 g/day of a mixture of raw nuts.
2. Continue to consume their usual diet, avoiding consumption of nuts.

Intervention type



Drug names

Primary outcome measure

Improvement of sperm vitality and motility. Semen samples will be collected at baseline and the end of the intervention period. All men will be instructed to abstain for 3 days prior to providing the study specimen, with abstinence period verified by self-report on day of sample collection. Semen samples will be collected allowing analysis within 60 min of sample production. A single researcher, who was blinded as to intervention versus control group status, will perform the conventional semen analyses. For the rest of analysis aliquots of semen will be frozen at -196ºC until analysis.

Secondary outcome measures

Semen samples will be collected at baseline and the end of the intervention period:
1. Other conventional semen parameters
2. Plasma lipid profile, glucose and insulin concentrations
3. Serum folic acid and alpha-linolenic concentrations
4. Sperm DNA fragmentation
5. Sperm ROS evaluation
6. Sperm miRNA expression profiles
7. Sperm DNA methylation
8. Sperm chromosome stability

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Healthy males
2. 18-35 years old
3. Reported a western-style diet

Participant type

Healthy volunteer

Age group




Target number of participants

118 (69 in control group and 69 in intervention group)

Total final enrolment


Participant exclusion criteria

1. Frequent consumption of nuts or a known history of allergy
2. Use of plant sterol or fish oil supplements and multivitamins, vitamin E or other antioxidant supplements
3. History of reproductive disorders or vasectomy
4. Current smokers
5. Taking antioxidant supplements or medications for chronic illness
6. Use of illegal drugs

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Universitat Autònoma de Barcelona
Facultat Biociències, Edifici C, despatx C2/-120
Bellaterra (Cerdanyola del Vallès)

Trial participating centre

Universitat Rovira i Virgili
C/Sant Llorenç, 21

Sponsor information


INC International Nut and Dried Fruit Council Foundation (Spain)

Sponsor details

Carrer de la Fruita Seca 4
Polígon Tecnoparc
+34 (0)977 331 416

Sponsor type




Funder type


Funder name

INC International Nut and Dried Fruit Council Foundation (Spain)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Impact for the scientific community and healthcare professionals
The dissemination plan will include participation in the major scientific events in the knowledge area (nutrition and dietetics, and fertility) such as: International Congress on Nutrition (IUNS); European Congress on Nutrition (ECN); Congress of the Sociedad Española de Nutrición (SEN); European Society of Human Reproduction and Embriology (ESHRE) congress; Congress of the Asociación Española de Biología de la Reproducción (ASEBIR). Participation is also envisaged in specific congresses for primary care physicians such as the Spanish Society of Family Medicine and Community Congress (SemFYC). It is also expected to publish the results in the best journals of medicine, nutrition and dietetics, fertility, and genetics.

Impact of the research on consumers
The dissemination plan is designed for both health care and consumers, and it includes social media (participation in radio and television for the target audience in both national and international media), and Internet networks (website, Facebook, Twitter). An animated whiteboard video will be produced to target a non-scientific audience and help visualize the scientific background and results of the study.

Impact on the industry
The results will be communicated using media press releases, and the website platform and networks of the International Nut and Dried Fruits Foundation.

Intention to publish date


Participant level data

Available on request

Basic results (scientific)

See additional file (ISRCTN12857940_BasicResults_29Nov18.pdf)

Publication list

1. 2018 results in:
2. 2019 results in:
3. 2019 results in: (added 20/06/2019)

Publication citations

Additional files

Editorial Notes

20/06/2019: Publication reference and total final enrolment added. 06/03/2019: Publication reference added. 29/11/2018: The basic results of this trial have been uploaded as an additional file. 27/11/2018: Publication reference added.