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One package of walnuts a day and you're a fertility god?
Last reviewed: 01.07.2025
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Eating 75 grams of walnuts a day increases sperm vitality, motility and morphology in healthy men aged 21 to 35, according to a study published in the journal Biology of Reproduction Papers-in-Press.
Around 70 million couples worldwide suffer from infertility, and in 30-50 percent of these cases it is the man who is unable to conceive. Some studies have shown that sperm quality has declined in men in industrialized countries, possibly due to pollution, unhealthy habits, and/or Western fast food.
Dr. Wendy Robbins and her colleagues at the University of California, Los Angeles, decided to study the issue of increasing polyunsaturated fatty acids (PUFAs). They play a crucial role in the process of sperm maturation and significantly affect membrane functions, which increases the quality of sperm in men who adhere to a Western diet.
The best sources of dietary PUFA in this eating style are fish, fish oil, flaxseed and walnuts, the last of which is a rich source of Linolenic acid, a natural plant source of omega-3.
With the support of the California Walnut Commission, Dr. Robbins' team recruited 117 healthy men aged 21 to 35 who ate a Western fast-food diet and divided them into two groups. The first group included 58 men who would not eat walnuts and the second group included 59 men who would eat 75 grams of walnuts a day. Previous studies have shown that 75 grams of walnuts is enough to change blood lipid levels without making the young men gain weight.
Before the experiment began and again after 12 weeks, the men's semen quality was analyzed according to routine male fertility parameters, including testing for sperm concentration, viability, motility, morphology, and chromosomal abnormalities.
After 12 weeks, the researchers found no significant changes in body mass index, weight, or activity levels in either group. However, the men who ate walnuts had significantly higher levels of omega-6 and omega-3 fatty acids, and improved sperm, vitality, motility, and morphology. They also had fewer chromosomal abnormalities in their sperm. The other group showed no changes.
While this study suggests that eating 75 grams of nuts a day may have a positive effect on a young man's sperm quality, it remains unknown whether such a diet will help young men with fertility problems and improve their reproductive ability.