The benefits of folate for women in preventing birth defects are well known, but new research suggests the nutrient also boosts sperm health, says a study in the journal Human Reproduction.
Men with relatively low levels of folate had increased risks for sperm containing either too few or too many chromosomes, according to researchers. These types of deficiencies can cause birth defects and miscarriages, the experts note.
Folate is one of the B vitamins and is found in leafy green vegetables, fruit, beans, chickpeas, and lentils. By law, breads and grains sold in the US are also specially fortified with added folate to help ward off birth defects.
"We looked at sperm to find different kinds of genetic abnormalities," says lead researcher Brenda Eskenazi, Ph.D., at the University of California, Berkeley's School of Public Health. "The abnormalities we looked at here were having too few or too many chromosomes. Normally, human sperm have 23 pairs of chromosomes."
Dr. Eskenazi continues, "In sperm you normally have one of each, but sometimes there are two and sometimes there are none of a particular chromosome."
If a normal egg was fertilized with one of these abnormal sperm, it could result in a birth defect, such as Down's syndrome, says Dr. Eskenazi.
"This can also result in an increase in miscarriage," she says.
The researchers looked at three specific chromosomes: X, Y, and 21. "We saw an association between [male] folate intake and how many abnormal sperm there were, in terms of the chromosome number for these three different chromosomes," says Dr. Eskenazi.
In the study, Dr. Eskenazi's group analyzed sperm from 89 healthy men. In addition, the researchers asked the men about their daily consumption of zinc, folate, vitamin C, vitamin E, and beta-carotene.
The researchers found that men who had the highest intake of folate had the lowest incidence of sperm abnormalities.
In fact, men who had the highest intake of folate - 722 to 1,150 micrograms a day - had a 20 percent to 30 percent lower frequency of several types of sperm abnormalities, compared with men who consumed less folate.
Up until now, birth-defect researchers have typically focused on women's diet in the period around conception, explains Dr. Eskenazi. "Based on these data, maybe men, too, need to consider their diet when they are considering fathering a child," she says.
Although this study does not conclusively prove a link between folate and chromosomal abnormality, Dr. Eskenazi advises men who are thinking of becoming fathers to increase their folate intake, perhaps with a supplement or a multivitamin containing folate.
This is not the first study to find a link between diet and sperm health. A report published last year in Human Reproduction found that women who ate beef seven or more times per week tended to produce sons with lowered sperm counts, perhaps due to the effects of hormones or pesticides on developing testes.
One expert agrees that healthy eating is linked to having healthy babies - even for men.
"This is another common-sense article that says good nutrition is associated with a better reproductive outcome," says Dr. Jamie Grifo, director of reproductive endocrinology at New York University Medical Center.
Dr. Grifo notes that rates of abnormal sperm seen in the Berkeley study were four to six per 1,000, which means that men with poor nutrition still had more than 99 percent normal sperm.
"Even though this may be the case, don't smoke, drink modestly, eat healthy unprocessed food, and take your vitamins," Dr. Grifo advises prospective fathers.
Always consult your physician for more information.
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Infertility is defined by the American Society for Reproductive Medicine (ASRM) as a disease of the reproductive system that impairs the body's ability to perform the basic function of reproduction.
Although conceiving a child may seem to be simple and natural, the physiological process is quite complicated and depends on the proper function of many factors.
The average chance to conceive for a normally fertile couple having regular, unprotected intercourse is approximately 25 percent during each menstrual cycle.
In most couples, conception occurs within about 12 months. However, infertility affects about 12 percent of couples of childbearing age. Infertility is not just a woman's concern.
A problem with the male is the sole cause, or a contributing cause, of infertility in about 40 percent of infertile couples.
About one-third of infertile couples have more than one cause or factor related to their inability to conceive. About 20 percent of couples have no identifiable cause for their infertility after medical investigation.
The following is a list of risk factors related to male infertility:
The main causes of male infertility can be divided into the following categories:
Or, normal sperm may be produced in abnormally low numbers (oligospermia) or seemingly not at all (azoospermia).
immotile cilia syndromes
liver disease, renal disease, or treatment for seizure disorders
Always consult your physician for more information.