Fish oil has cardiovascular benefits, reducing inflammation and lowering cholesterol levels. But if you're trying to get pregnant, you may have more interest in fish oil's effects on something more crucial to reproductive function -- sperm. While several animal and human studies have been conducted on the effects of fish oil on sperm, none have shown an increase in sperm count as a benefit.
Researchers from Vanderbilt University assessed the effects of 50 mg of 50 ml menhaden oil daily for one month on human semen. Their results, reported in the April 1990 issue of "Prostaglandins," found no change in sperm count or motility after treatment with the fish oil.
A human study conducted by researchers from the University of Guelph and reported in the February 2000 issue of "Lipids" tested the effect of docosahexaenoic acid, or DHA, one of the fatty acids in fish oil, on sperm motility. Researchers found no improvement in sperm motility after supplementation with 400 or 800 mg of DHA or placebo for three months in men with low sperm motility. The study did not examine the effect on sperm count.
Animal studies have shown some benefit in increasing sperm motility, but not sperm count. An article in the February 2001 issue of "Reproduction" by British researchers reported that 30 g of tuna oil daily increased progressive sperm motility and decreased the number of abnormal sperm in pigs. A Canadian study published in the July 2010 issue of "Journal of Animal Science" found no increase in sperm production in boars treated with menhaden oil. Boars treated with a combination of fish oil and biotin actually had a decrease in the number of normal sperm.
Few studies have been conducted yet on the benefits of fish oil for sperm count or other sperm factors that play a part in fertility, such as motility, or forward progression. Fish oil contains antioxidants that decrease damage to cellular DNA, but this benefit has not yet been shown to help sperm. If you have fertility issues related to sperm count, talk to your doctor about possible treatments before supplementing with fish oil.