NEW YORK (Reuters Health) - Young men whose mothers took folic acid supplements while pregnant did not grow up to produce healthier sperm, a small Danish study has found.
The research, published in the journal Fertility and Sterility, was the first to compare the quality of sperm from sons of mothers-to-be who took folic acid with sperm from men whose mothers did not take the B vitamin.
Because B vitamins are important to many processes in the body, and folic acid (vitamin B9) is critical to fetal development, the Danish team wanted to see if a mother's intake would affect her son's later reproductive health.
Because the study was small, however, other researchers say they view the results with caution.
Dr. Elizabeth Ginsburg, an obstetrician-gynecologist at Brigham and Women's Hospital in Boston who was not involved in the study, called the evidence "skimpy."
"I wouldn't be comfortable telling somebody that folic acid would have no effect on their subsequent sons' sperm function," she said.
The study's authors were unavailable for comment.
Their results were based on sperm samples collected in 2004 from the sons of Danish women enrolled in a study on reproductive health between 1984 and 1987 while they were pregnant.
Among a total of 347 young men, the number, mobility, and shape of sperm cells -- factors that help clinicians assess a man's fertility -- did not significantly vary, regardless of whether or not a man's mother had taken folic acid while pregnant.
For example, men whose mothers took folic acid during pregnancy had an average sperm count of 114 million per sample; among men whose mothers didn't take the B vitamin, that number was 110 million.
Both figures are well above the 40 million sperm count considered the minimum for normal fertility by the World Health Organization.
Previous studies have explored the effects of folic acid on sperm quality when taken by men during adulthood, but the results have proven ambiguous.
"There are no conclusive studies that show folic acid changes the quality of semen either way," said Dr. Irene Su, an assistant professor of reproductive endocrinology and fertility at the University of California, San Diego.
Although folic acid might not have an effect, there are other ways men can boost the quality of their sperm.
"There is growing evidence to suggest antioxidants are beneficial for men's fertility," said Dr. James Smith, director of the Male Reproductive Health Center at the University of California, San Francisco.
Eating antioxidant-rich foods, such as kale and blueberries, or taking an antioxidant supplement are simple ways to boost intake.
In addition, men should avoid activities that expose the groin to excessive heat, since this can make them less fertile, noted Ginsburg. When it comes to this area of the body, she said, "anything that increases the temperature can decrease fertility, including bicycling and spending time in a hot tub."
Regardless of folic acid's role in male fertility, it plays a key role in normal fetal development and will remain an important part of doctors' recommendations to women who are pregnant or may become pregnant, said Su.
The U.S. Centers for Disease Control and Prevention recommend that women of childbearing age get at least 400 micrograms of folic acid daily.
Because folic acid is so important for the development of the fetus, said Su, "it won't change what we (as doctors) do: recommend every pregnant woman take folic acid supplements every day."
SOURCE: bit.ly/klJctS Fertility and Sterility, online June 10, 2011.