Effect of Walnuts on Sperm Parameters and Male Fertility

The investigators are testing the hypothesis that two ounces of whole-shelled walnuts/day added to the diet of men seeking care for infertility will beneficially affect sperm parameters and fertility. The investigators will compare the walnut intervention to the commonly suggested recommendation of adding an OTC multivitamin supplement to the diet.

Study Overview

• Status: Completed
• Conditions: Fertility; Oligozoospermia; Asthenozoospermia; Teratozoospermia
• Intervention / Treatment: Dietary supplement: Walnuts; Dietary supplement: OTC multivitamin

Detailed Description

Purpose: The investigators are testing the hypothesis that two ounces of whole-shelled walnuts/day added to the diet of men with oligo- astheno- or teratospermia will beneficially affect sperm parameters. The investigators found in a previous study (Robbins et al. 2012, Biology of Reproduction 87(4):101, 1-8.) that walnuts added to a Western diet improved sperm parameters in healthy, young men of unknown fertility and the most improvement occurred in participants with poor sperm parameters at baseline. The investigators now test the walnut dietary intervention in a fertility clinic population known to have poor sperm parameters. The investigators will compare the walnut intervention to the usual care suggestion of adding an OTC multivitamin supplement to the diet. Neither walnuts nor the OTC multivitamin have been tested for efficacy in this fertility clinic population previously.

Methods: A randomized, parallel two-group, dietary intervention trial with single-blind masking of outcome assessors will be conducted with up to 140 men who present for fertility work-up with semen parameters below the 25th centile for count, and 10th centile for motility and/or morphology according to the WHO 5th Edition, Laboratory Manual for the Processing and Examining of Human Semen, 2010. Repeated measures at baseline and 12 weeks include: semen analyses (primary outcome), blood fatty acid/ nutrient profiles (secondary outcomes); IPAQ physical activity questionnaire and IIEF index of erectile function (potential modifiers or confounders). Dietary intake will be assessed throughout using 24-hour ASA dietary recall x 5 and fertility assessed by questionnaire at one year post enrollment.

• Study Type: Interventional
• Enrollment (Actual): 80
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Los Angeles, California, United States, 90095
      • University of California Los Angeles
    • Los Angeles, California, United States, 90048
      • Male Reproductive Medicine and Microsurgery Clinic, Cedars-Sinai Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Male

Description

Inclusion Criteria:

• Age 21 years or older
• Sperm concentration < or = to 41 million per ml
• Sperm motility < or = to 40%
• Normal sperm morphology forms < or = to 5.5%
• Patients of Howard H. Kim, MD seen at the Male Reproductive Medicine and Microsurgery Clinic, Cedars-Sinai Medical Center, Los Angeles, California
• Have eaten walnuts throughout life without adverse reaction

Exclusion Criteria:

• Allergy to walnuts or tree nuts
• Food allergy
• Known genetic cause of infertility
• Known anatomical cause of infertility
• History of seizure disorder

Study Plan

How is the study designed?

Design Details

• Primary Purpose: TREATMENT
• Allocation: RANDOMIZED
• Interventional Model: PARALLEL
• Masking: SINGLE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Walnuts; 2 ounces whole-shelled walnuts per day for 12 weeks	Dietary supplement: Walnuts
ACTIVE_COMPARATOR: OTC (over-the-counter) multivitamin; OTC multivitamin tablet 2 per day for 12 weeks	Dietary supplement: OTC multivitamin

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sperm count	Change from baseline to three months in sperm count	12 weeks
Sperm motility	Change from baseline to 12 weeks in sperm motility	12 weeks
Sperm morphology	Change from baseline to 12 weeks in sperm morphology	12 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fertility	Fertilization of ova through natural conception or assisted reproductive technology	12 months
Blood fatty acid and nutrient profile	Change from baseline to 12 weeks in blood fatty acid profile and nutrients	12 weeks
Sperm aneuploidy	Change from baseline to 12 weeks in sperm aneuploidy	12 weeks
Sperm DNA strand breakage	Change from baseline to 12 weeks in sperm DNA integrity	12 weeks

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Physical Activity	IPAQ (International Physical Activity Questionnaire) assessment of change from baseline to 12 weeks	12 weeks
Sexual function	IIEF (International Index of Erectile Function) assessment of change from baseline to 12 weeks	12 weeks
Dietary intake	ASA-24 (Automated Self-administered) 24-hour dietary recalls x 5 over 12 weeks	12 weeks

Collaborators and Investigators

• Sponsor: University of California, Los Angeles
• Collaborators: Cedars-Sinai Medical Center
• Investigators: Principal Investigator: Howard H Kim, MD, Cedars-Sinai Medical Center, Los Angeles, CA

Publications and helpful links

General Publications

• Robbins WA, Xun L, FitzGerald LZ, Esguerra S, Henning SM, Carpenter CL. Walnuts improve semen quality in men consuming a Western-style diet: randomized control dietary intervention trial. Biol Reprod. 2012 Oct 25;87(4):101. doi: 10.1095/biolreprod.112.101634. Print 2012 Oct.

Study record dates

Study Major Dates

• Study Start: May 1, 2014
• Primary Completion (ACTUAL): March 1, 2020
• Study Completion (ACTUAL): March 1, 2020

Study Registration Dates

• First Submitted: September 20, 2013
• First Submitted That Met QC Criteria: September 26, 2013
• First Posted (ESTIMATE): October 1, 2013

Study Record Updates

• Last Update Posted (ACTUAL): December 1, 2020
• Last Update Submitted That Met QC Criteria: November 30, 2020
• Last Verified: November 1, 2020

More Information

Terms related to this study

• Keywords: Randomized controlled trial; Nutrition; Sperm; Male Infertility; Spermatozoa; Walnuts; Male Reproduction
• Additional Relevant MeSH Terms: Infertility, Male; Infertility; Oligospermia; Asthenozoospermia; Teratozoospermia
• Other Study ID Numbers: 20130929