Researchers from the University of Illinois studied mice that were created to lack a gene that helps them produce the fatty acid DHA. These mice were found to have fewer sperm and more abnormalities in what little sperm they did have, but such effects were reversed in mice fed DHA.
"In our experiment, we used 'knockout' mice that lacked the gene responsible for an enzyme important in making docosahexaenoic acid (DHA). In the absence of DHA, male mice are basically infertile, producing few if any misshaped sperm that can't get where they need to go," the lead researcher said.
"We looked at sperm count, shape, and motility and tested the breeding success rate, and the mice lacking DHA simply were not able to breed."
In the DHA-deficient knockout mice, sperm counts were extremely low. The sperm that were produced were round instead of elongated and they were unable to move well.
This is the first time that the importance of DHA to male fertility has been shown this directly, although some studies have suggested that male fertility patients with low sperm counts and less motile sperm tend to have low levels of this fatty acid.
A study from Iran earlier this year reported a link between omega-3 fatty acids and sperm quality and fertility. They found that infertile men had lower levels of omega-3 fatty acids in their sperm than fertile men. The study included 150 men and was published in the journal Clinical nutrition (February 2010, Vol. 29, pp. 100-105).
"To our knowledge, this is the first study evaluating the association of omega-3 and omega-6 fatty acids on semen quality, and seminal plasma anti-oxidant capacity in infertile and fertile men," they added.
The findings are biologically plausible, noted the Iranian researchers, with DHA, for example, known to be present in the membranes of sperm.
Omega-3 fats For Better Health
These findings add fertility to the long list of potential benefits of omega-3 fatty acids, including improved heart health, strengthening the immune system and protecting against cancer. The brain is also highly dependent on DHA - low DHA levels have been linked to depression, schizophrenia, memory loss, and a higher risk of developing Alzheimer's.
Fish oil, cod liver oil and krill oil are all excellent sources of omega-3 fatty acids. Oily fish like salmon, mackerel, sardines and herring also provide good sources of this nutrient, as well as seeds like flax, pumpkin, chia, hemp and the unprocessed, unrefined oils of these seeds.
Research Paper Details:
M. Roqueta-Rivera, C.K. Stroud, W.M. Haschek, et al. Docosahexaenoic acid supplementation fully restores fertility and spermatogenesis in male delta-6 desaturase-null mice. Journal of Lipid Research Vol 51, Pages 360-367.