Benefits of Walnuts for Male Reproductive Health
Condition: Infertility; Nutrition Disorders
MeSH terms: Infertility; Nutrition Disorders
Study type: Interventional
Phase: Phase 2

Summary: 
      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.
    

Detailed description: 
      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:

        1. 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

        2. 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

        3. Compare intervention and control groups at three months on blood and semen measures

        4. Compare blood and semen measures within man between baseline and three months.
    

Intervention name(s): Whole walnuts
Intervention type(s): Other
Intervention description(s): 75 gm whole walnuts per day will be consumed with usual Western style diet
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Prevention
Keywords: Andrology; Fertility; Reproduction; Diet; Nutritional Sciences; Fatty Acids; Antioxidants; Body weight changes