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Research from the University of California, Los Angeles (UCLA) has determined that eating 75 grams of walnuts a day for three months increases men's sperm count and fertility
The researchers recruited 117 young men in healthy condition who consumed a typical western diet for this single-blinded, randomized trial. They gave 59 of the men 75 grams of walnuts per day for twelve weeks. The other 58 men avoided tree nuts altogether.
The men's sperm and blood were tested before and after the twelve week trial. Those who ate walnuts had a significant improvement in their sperm vitality, their sperm motility and their sperm morphology. Sperm aneuploidy - problems with chromosome quality - was also significantly reduced among the walnut group.
Epidemiological research has estimated that some 70 million couples around the world suffer from infertility issues. From 30% to 50% of infertility issues are due to fertility among men. Between three and five million men seek fertility treatments every year.
The research was led by UCLA Professor Wendie Robbins, Ph.D., R.N. "The positive finding of walnuts on sperm may be a result of their unique nutrient profile," Dr. Robbins stated after the study.
Dr. Catherine Carpenter, an associate professor of medicine at UCLA added that "these findings are not surprising when you look at the nutritious content of walnuts, however the results are amazing considering the impact they might have on men of all ages, including older men, and men with impaired fertility."
The research findings correlated fertility improvement with the walnuts' alpha-linolenic acid content, along with other nutrients.
Dr. Robbins suggested that the male's diet is rarely considered in modern fertility issues. "Diet is not just maternal territory anymore," she added.
Walnuts contain a host of nutrients. A cup of chopped walnuts will contain 18 ounces of protein, or about 15% by weight. Walnuts also contain a host of B vitamins, led by folate at 115 mcg, B6 at 600 mcg and thiamin at 400 mcg. A cup of walnuts also contains 115 milligrams of calcium, 185 milligrams of magnesium and 516 milligrams of potassium. Walnuts are also rich in manganese - with 200% of US Daily Value. Walnuts are also rich in selenium and phytosterols.
But it is walnuts' omega-3 content that blows the doors off of most foods, at 10,623 milligrams of omega-3s per cup. Much of this comes in the form of alpha-linolenic acid (ALA). Healthy livers convert ALA to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) as needed, at a rate of between 7% and 36%.
Studies of men and women conducted at the UK's University of Southampton found an average conversion rate of 36% from ALA to EPA, DHA and other N-3s in women and 16% in men. The liver converts ALA using the delta-6-desaturase and elongase enzymes.
It is not surprising that walnuts have been shown to reduce LDL-cholesterol, improve artery health, reduce blood pressure and reduce inflammation in multiple studies.
1. Robbins WA, Xun L, Fitzgerald LZ, Esguerra S, Henning SM, Carpenter CL. Walnuts Improve Semen Quality in Men Consuming a Western-Style Diet: Randomized Control Dietary Intervention Trial. Biol Reprod. 2012 Aug 15.
2. Burdge GC, Jones AE, Wootton SA. Eicosapentaenoic and docosapentaenoic acids are the principal products of alpha-linolenic acid metabolism in young men. B J Nutr. 2002 Oct;88(4):355-63.
3. Burdge GC, Wootton SA. Conversion of alpha-linolenic acid to eicosapentaenoic, docosapentaenoic and docosahexaenoic acids in young women. B J Nutr. 2002 Oct;88(4):411-20.
4. Vinson JA, Cai Y. Nuts, especially walnuts, have both antioxidant quantity and efficacy and exhibit significant potential health benefits. Food Funct. 2012 Feb;3(2):134-40.
5. West SG, Krick AL, Klein LC, Zhao G, Wojtowicz TF, McGuiness M, Bagshaw DM, Wagner P, Ceballos RM, Holub BJ, Kris-Etherton PM. Effects of diets high in walnuts and flax oil on hemodynamic responses to stress and vascular endothelial function. J Am Coll Nutr. 2010 Dec;29(6):595-603.
6. Damasceno NR, Pérez-Heras A, Serra M, Cofán M, Sala-Vila A, Salas-Salvadó J, Ros E. Crossover study of diets enriched with virgin olive oil, walnuts or almonds. Effects on lipids and other cardiovascular risk markers. Nutr Metab Cardiovasc Dis. 2011 Jun;21 Suppl 1:S14-20. Epub 2011 Mar 21.
7. Um CY, He K. Long-term walnut supplementation without dietary advice induces favorable serum lipid changes in free-living individuals. Eur J Clin Nutr. 2011 Mar;65(3):421; author reply 422.
8. Din JN, Aftab SM, Jubb AW, Carnegy FH, Lyall K, Sarma J, Newby DE, Flapan AD. Effect of moderate walnut consumption on lipid profile, arterial stiffness and platelet activation in humans. Eur J Clin Nutr. 2011 Feb;65(2):234-9.
9. Walnuts and arteries. Harv Heart Lett. 2010 May;20(9):6.