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Completed

NCT Number: NCT01505140

Benefits of Walnuts for Male Reproductive Health

Walnuts as a whole food contain polyunsaturated fatty acids, anti-oxidants, and other nutrients essential to sperm development and function. This randomized controlled trial sought to determine if a Western style diet supplemented with walnuts would improve sperm quality as a predictor of male fertility.

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Key information

Conditions

Infertility Body Weight Body Weight Changes Genital Diseases Nutrition Disorders Nutritional and Metabolic Diseases Pathological Conditions, Signs and Symptoms Signs and Symptoms Urogenital Diseases

Age range

21 year–35 year

Sex eligibility

Male

Study type

Interventional

Phase

Phase 2

Primary location

University of California, Los Angeles

Los Angeles, California, 90095-6919, United States

About this study

A vast research base on human sperm shows the following to be critical for normal sperm development and function: Polyunsaturated fatty acids provide fluidity to sperm membranes allowing sperm to swim, fuse with ova, and support key cellular functions. Antioxidants protect sperm from reactive oxygen species generated during normal physiologic processes or white blood cells that infiltrate into seminal fluid and injure membranes and fragment sperm DNA. Selenium is critical in the form of anti-oxidant selenoproteins protecting developing sperm in the testes and later selenium in the epididymis participates in cell shape for motility. Folate, in a recent study, was associated with decreased aneuploidy (abnormal number of chromosomes)in sperm. Deficiency in any of these factors - lipids, antioxidants, selenium, or folate could manifest as poor semen quality and sub-fertility.

Walnuts provide a rich dietary source of each of the critical factors discussed above. Walnuts contain beneficial lipids, antioxidants, selenium, and folate. Walnuts, as a natural whole food source, may be preferential to commercial supplements and, as a plant source of nutrients, leave a positive green footprint on the planet.

Hypothesis The investigators hypothesize that diets enriched in walnuts will improve semen quality. Semen quality is a predictive marker for male infertility and sub-fertility, thus, the overall goal is to determine if dietary intake of walnuts will benefit male reproductive health.

A randomized, controlled intervention will be used to study the effects of walnut supplementation on semen quality measures in young men (ages 21 to 35) eating Western diets. Participants will be enrolled from the West Los Angeles area (n=120). Men will be randomly assigned to consume 3 oz of walnuts per day as part of their usual diet or to continue their habitual diet but avoid nuts. Each will follow the assigned diet for three months to cover one complete cycle of spermatogenesis.

The specific aims of the study are to:

  • Establish at baseline: habitual diet; serum omega-3 to omega-6 ratio, serum selenium and folate; semen quality (sperm count, motility, morphology) and sperm DNA integrity (COMET assay); sperm aneuploidy; and semen anti-oxidant levels
  • Randomly assign men to habitual diet plus 3 oz walnuts per day or usual diet without nuts for three months monitored by six telephone 24 hour dietary recalls
  • Compare intervention and control groups at three months on blood and semen measures
  • Compare blood and semen measures within man between baseline and three months.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Males

  • Age 21 to 35 years
  • Residence is in West Los Angeles for the next three months
  • Non-smoker
  • Free from chronic diseases requiring medications
  • Free from nut allergies or nut intolerance
  • Not taking anti-oxidant supplements

Exclusion criteria

  • Outside the age range of 21 to 35 years
  • Residence outside West Los Angeles area prohibiting two trips to the clinical research laboratory
  • Current smoker
  • Taking medications for chronic disease
  • Nut allergies or nut intolerance
  • Taking anti-oxidant supplements -

Treatment and study plan

Whole walnuts

Other

75 gm whole walnuts per day will be consumed with usual Western style diet

Primary outcomes

  1. change from baseline in semen quality at 12 weeks

    Time frame: change from baseline at 12 weeks

    semen quality is measured as sperm count, motility, vitality, morphology, DNA integrity

  2. change from baseline in serum fatty acids at 12 weeks

    Time frame: change from baseline at 12 weeks

  3. change from baseline in serum selenium at 12 weeks

    Time frame: change from baseline at 12 weeks

  4. change from baseline in serum folate at 12 weeks

    Time frame: change from baseline at 12 weeks

  5. change from baseline in serum zinc at 12 weeks

    Time frame: change from baseline at 12 weeks

Secondary outcomes

  1. change from baseline in body weight pounds at 12 weeks

    Time frame: change from baseline at 12 weeks

  2. change from baseline in nutrient intake at 12 weeks

    Time frame: change from baseline at 12 weeks

Sponsors and collaborators

Lead sponsor

University of California, Los Angeles

Other

Collaborators

  • California Walnut Commission

Registry information

Important dates

Study start
2009
Primary completion
2010
Study completion
2010
First posted
Jan 6, 2012
Registry last updated
Nov 28, 2016

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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