In a recent article in the journal Biology of Reproduction, healthy young men exhibited a small but statistically significant improvement in sperm health after adding walnuts to their diet.
About the study
The article “Walnuts Improve Semen Quality in Men Consuming a Western-Style Diet: Randomized Control Dietary Intervention Trial “ was the result of research from UCLA. The study was partially paid for by the California Walnut Commission. This 12-week study of men ages 21 to 35 years involved 117 participants who were randomly assigned to one of two groups.
In the first group, 58 men were asked to avoid eating tree nuts. In the second group, 59 men were asked to eat 75 g (approximately 2.5 ounces) of whole-shelled English walnuts daily. In both groups, there were no significant changes in exercise levels, body weight or body mass during the study.
At the end of the 12 weeks, the men that ate the walnuts showed improvements in sperm motility, vitality and morphology. Additionally, their sperm showed fewer chromosomal abnormalities. The men in the walnut group also showed increased serum levels of omega-6 and omega-3 fatty acids from baseline. However, there were no changes in serum folate or sex hormone levels.
The authors conclude that walnuts improved sperm development and function. Walnuts were also associated with increases in omega-3 ALA and omega-6 fatty acids. While walnuts appear to improve sperm function and development, it is not currently known if walnuts will help improve male fertility and improve birth outcomes. Further research is required.
Walnuts offer rich sources of alpha linolenic acid (ALA), a natural plant source of omega-3. Walnuts are a calorie-dense, protein-rich food source high in fiber and containing omega-6 fatty acids, anti-oxidants and micronutrients.
Past research has shown that high intake of omega-3 fats in men is linked to more normal sperm size and shape while high intake of saturated fats has been linked to lower sperm concentration. Another study showed improvements in sperm counts in men taking fish oil supplements high in omega-3 fats.
What we can learn from this?
A typical “Western” diet often lacks optimal PUFA (polyunsaturated fatty acids). The best-known dietary sources of PUFAs include the following:
- Cold-water oily fish
- Fish oil supplements
- Flax seed
- Tree nuts (almonds, cashews, pecans, walnuts, and others)
My take on this issue
This interesting research indicates that eating 75 grams of walnuts per day can positively affect a young man’s sperm quality. Still, it is unknown whether walnuts offer benefits to male fertility. As walnuts are part of a healthy diet, it seems reasonable to recommend walnuts to men who are attempting pregnancy, especially if they are not supplementing with anti-oxidants and PUFA’s.
Dr. Carmelo Sgarlata is a leading Reproductive Endocrinology and Infertility specialist at the Reproductive Science Center of the San Francisco Bay Area. With over 25 years of experience and well over 1,000 babies born through his guidance, Dr. Sgarlata has become well known in the community where he lives and practices. His areas of special interest include Operative Laparoscopy and Hysteroscopy, Ovulation disorders including diminished ovarian reserve and recurrent pregnancy loss.