Infertility affects up to 15 percent of couples. In up to a third of these couples, male infertility plays a role. Male infertility is due to low sperm production, abnormal sperm function or blockages that prevent the delivery of sperm. Illnesses, injuries, chronic health problems, lifestyle choices and other factors can play a role in causing male infertility. Medical causes of infertility are numerous. They include: Hormone imbalances, Antibodies that attack sperm, Celiac disease, Infection, Certain medications, Heavy metal exposure, Industrial chemicals, Radiation or X-rays, Overheating the testicles. Genetic causes include: Chromosome defects like Klinefelter's syndrome, Cystic fibrosis and Kallmann's syndrome. Recently studies have associated some variants of the MTHFR gene with male infertility1.
The MTHFR gene provides instructions for making an enzyme called methylenetetrahydrofolate reductase - a key enzyme in the folate metabolism pathway which regulates DNA methylation, synthesis, and repair. The MTHFR enzyme catalyzes the conversion folate found naturally in foods, to its active form. Impairment of this process leads to build up of Homocysteine which is a potentially toxic amino acid and cardiovascular risk factor.
A study1 found positive correlation between folate concentrations and sperm density, percentage of sperm with progressive motility, as well as percentage of sperm with normal morphology.