Folate May Help Keep Sperm in Shape
Wednesday, February 28, 2001
Young men who want to keep themselves satisfactorily stocked with sperm should make sure they're getting enough folic acid in their diets, UC Berkeley researchers have reported.
In a collaborative study with the USDA's Western Human Nutrition Research Center, a team of UC Berkeley scientists has found that eating plenty of fruits and vegetables not only keeps a man healthy, but may also help keep his sperm in top-notch shape.
In their study, a team of scientists, led by UC Berkeley assistant research scientist Lynn Wallock, analyzed the seminal fluids from 48 male volunteers.
Semen samples were taken from two groups of men-a set of 24 smokers and another group of 24 non-smokers.
Wallock, who conducted the study with the WHNRC's Robert Jacob, examined the semen specimen for two folic acid forms and found that men with lower levels of the vitamin in their seminal fluids tended to have a lower sperm count and lower sperm density as well.
"We looked for statistical associations," Wallock said. "We looked between a continuum of folic acid levels and semen quality measures."
The findings suggest that folic acid is necessary to ensure the quality for viability of a man's sperm.
Furthermore, the scientists suggest that the genetic quality of man's sperm may likely play a significant role in the health of his future children.
The scientists hypothesize that insufficient amounts of folic acid could compromise a man's ability to synthesize and repair its sperm DNA-an event that could explain the observed reduction in sperm levels.
Such an event, they suggest, could lead to a higher frequency of breaks in the chromosome, which may contribute to an increased risk of childhood cancer in a man's offspring.
"(Folic acid) could prove to be important for maintaining the integrity of the DNA in the sperm," said Wallock, who works in the laboratory of UC Berkeley Molecular and Cell Biology professor Bruce Ames, located at the Children's Hospital Oakland Research Institute.
Folic acid, also known as folate, is a B vitamin present in a variety of foods, including orange juice and green, leafy vegetables. The vitamin is also present in many fortified grain products.
Deficiency of folic acid has been linked to such ailments as anemia and poor growth.
In addition, the vitamin's effects have been studied extensively in women, especially those who plan to become and who are pregnant.
The Centers for Disease Control estimates that two-thirds of women in the United States do not consume adequate amounts of folic acid.
In women, insufficient intake of folate has been found to correlate with a higher risk of having children with birth defects such as spina bifida-a neural tube disorder that occurs when the lower end of the neural tube fails to close and which leads to the improper development of the spinal cord and back bones.
Previous research has shown that it is important for a woman to have enough folic acid in her body both before and during pregnancy.
While most study has focused on the role of folate in women, this latest finding reports the importance of the folic acid in reproducing men, whose sperm contributes half of the DNA to a couple's offspring.
"It's something that people have not explored," Wallock said. "We were looking at seminal fluid, and that's a poorly examined research area."
Folic acid may be vital to proper sperm development because it is required for the production of DNA.
The vitamin comes in two forms-a methyl form and a non-methyl form, which was found to be correlated with lower sperm count and density.
During DNA synthesis, the non-methyl form of folate is essential to convert the nucleic base, uracil, into thymine-one of four nucleic bases that make up DNA.
In their work at the Children's Hospital Oakland Research Institute, Ames and Wallock proposed in 1997 that an absence of folic acid leads to decreased thymine synthesis in the body's cells.
Inadequate amounts of thymine, they hypothesized, may lead to the subsequent incorporation of the wrong nucleic base, uracil, into DNA.
The more frequent need for a cell's DNA repair machinery to correct this mitake, could, in turn, contribute to greater risk of chromosome breaks, they said.
As a result, folic acid, Wallock said, may be important for ensuring the integrity of the DNA contained in sperm because of its role in synthesis and repair of sperm DNA.
Poor DNA repair mechanisms increase the risk of genetic damage and, subsequently, raise the risk of cancer in the offspring, scientists said.
Adequate amounts of the vitamin are very critical for women, particularly during the period before conception and during early fetal development.
Because sperm is manufactured constantly in males, folic acid is important during all stages of life.
"Men are making sperm all the time and their dietary habits could be important in maintaining the quality of the sperm," Wallock said.
To ensure adequate levels of folic acid consumption, scientists recommend that men and women eat well-balanced meals, full of green vegetables and fortified grains.
"Because I'm a nutritionist, I always recommend people improve their diets before a supplement," Wallock said. "(Folate) is commonly found in leafy greens, orange juice, legumes and fortified grain products. My first recommendation would be to eat five to nine servings of fruits and vegetables a day."
Supplements can also be taken for extra precaution to protect sperm quality and lower the risk of infertility, said Wallock, who is a nutritionist.
"A modest vitamin and mineral supplement is not a bad thing, but trying to improve the diet with food should always be a first choice," she said. "A vitamin containing the RDA of 400 micrograms per day wouldn't hurt."
Overconsumption of folate, however, will not cause men to produce excessively high amounts of sperm.
Although there are no directly dangerous consequences of folate overdose, making sure not to consume too much of the vitamin should be a precaution as well, Wallock said.
"You can overdo it," she said. "(Men) shouldn't go overboard on taking lots of folic acid. If people take too much, it could mask a vitamin B-12 deficiency."
Too much folate in the diet can cause a masking of the anemia associated with inadequate vitamin B-12 intake.
For the future, the scientists hope to conduct further research into the specific genetic damage that may occur due to a deficiency in folate.
"All we did in this study was count the sperm and make measurements," Wallock said. "We would like to look at the integrity of the DNA inside the sperm. Our future studies will be aimed at looking at the quality of the DNA and seeing if low folic acid negatively affects the quality of DNA."
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