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.
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
SINGLE
Enrollment
120
75 gm whole walnuts per day will be consumed with usual Western style diet
University of California, Los Angeles
Los Angeles, California, United States
change from baseline in semen quality at 12 weeks
semen quality is measured as sperm count, motility, vitality, morphology, DNA integrity
Time frame: change from baseline at 12 weeks
change from baseline in serum fatty acids at 12 weeks
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change from baseline in serum selenium at 12 weeks
Time frame: change from baseline at 12 weeks
change from baseline in serum folate at 12 weeks
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change from baseline in serum zinc at 12 weeks
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change from baseline in body weight pounds at 12 weeks
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change from baseline in nutrient intake at 12 weeks
Time frame: change from baseline at 12 weeks
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