By Tamara McLean
The discovery surprised Sydney researchers investigating the incidence of DNA fragmentation of sperm, a significant factor in male infertility.
Sunlight is the major source of vitamin D, which helps regulate levels of calcium and phosphorous to generate healthy bones.
Fertility specialist Dr Anne Clark screened the blood of almost 800 men with fertility problems, finding almost a third had lower than normal levels of vitamin D.
"In a significant number of these men, there were also elevated levels of homocysteine, an amino acid in the blood associated with cell toxicity, and deficiency in folate, which is essential for healthy new cells," said Dr Clark, medical director of the treatment centre Fertility First.
"Men in the study group who agreed to make lifestyle changes and take dietary supplements had surprisingly good fertility outcomes." Dr Clark said the study's results were unexpected.
"Vitamin D and folate deficiency are known to be associated with infertility in women, but the outcomes of the screening among men in our study group came as a complete surprise."
Dr Clark said concerns about skin cancer could be a contributing factor to vitamin D deficiency among men, along with work and lifestyle choices, avoiding too much direct sunlight exposure.
"If that is the case, one wonders if the outcomes in the study group also raise the possibility of significant vitamin D deficiency in the broader public, and its effect on fertility levels," she said.
Of the 794 men tested, 58 per cent were shown to have high levels of DNA fragmentation, according to results to be presented at a national fertility conference in Brisbane tomorrow.
About 100 of the men agreed to quit smoking, minimise or stop their intake of caffeine and alcohol, reduce weight and take a three-month course of vitamins and antioxidants before commencing fertility treatment.
Most significantly improved their sperm quality and 40 per cent went on to achieve a clinical pregnancy, with 11 occurring naturally.
"The results clearly show that lifestyle changes and dietary supplements can be beneficial for the conception of a healthy on-going pregnancy," Dr Clark said.