Researchers in New Zealand and Australia have a hunch that antioxidants-long touted to decrease the risk of cancer and heart disease-may also help fertility-challenged couples to conceive.

Cochrane Library lead researcher Marian Showell, who works in obstetrics and gynecology at the University of Aukland in New Zealand, recently reported the results of a small study of 2,876 couples and the effects of oral antioxidants on "subfertile" males. All of the couples in the study were undergoing in vitro fertilization (IVF), sperm injections, or other assisted reproductive methods.

Male subfertility affects one in 20 men. Men with the condition produce sperm at lower amounts than normal.

In men with male subfertility, the fertilizing capacity of the sperm is reduced due to raised concentrations of reactive oxygen species (ROS) in semen. The presence of ROS in semen may damage the cell membrane. ROS is also said to alter the sperm's DNA.

Showell said that the quality of sperm DNA is the major factor affecting normal membrane growth in both natural and assisted conception. The New Zealand study attempted to test whether antioxidants including natural and synthetic chemicals, as well as certain vitamins and minerals, reduce the damage caused by ROS.

"Oral antioxidants such as Vitamin E, L-carnitine, zinc, and magnesium act as scavengers to overcome reactive oxygen species," said Showell, explaining how antioxidants assist the sperm cells.

However, critics contend that the data is weak. Edmond Confino, MD, a reproductive endocrinologist and gynecologist at Northwestern Memorial Hospital in Chicago said in a press release that compared subjects receiving different modes of conception treatment--some were receiving IVF, some were undergoing other types of assistance--introduces possible complicating factors that weren't addressed in the small study.

By all accounts, reproduction is a complicated process. Further research is needed to gather information about which antioxidant--vitamin E, L-carnitine, zinc and magnesium, or some other combination-is best and under what conditions. For example, the results of the study don't tell us at which point during conception antioxidant intervention is most beneficial.

There's also very little information about adverse side effects associated with oral antioxidants. "There was some gastro and intestinal upset associated with the antioxidants, but the side effects were poorly reported," admits Showell in the podcast.

Until further research is completed, however, Showell and her colleagues feel hopeful that antioxidants hold promise for couples experiencing the heartbreak of infertility.


The Cochrane Library

Northwestern University, Medill School of Journalism

The British Medical Journal