This study was aimed at determining the effects of dietary zinc, antioxidants vitamins C, E and beta-carotene, and folate on changes in sperm quality. Sperm samples were obtained from the 89 healthy non-smoking male participants in this study. They also filled in a questionnaire regarding their intake of dietary zinc, folate, vitamin C, vitamin E and beta-carotene, or supplements of the same. It was observed that those having higher intake of folate had a lower frequency of sperm abnormalities. However, there was no significant influence on sperm quality by zinc or antioxidant levels.
Abnormal sperm are involved in approximately 5 percent of pregnancies and could be responsible for more than one-third of all spontaneous abortions. Although the mechanisms are poorly understood, increase in abnormalities could occur with increasing paternal age, smoking, pesticides, alcohol and the lack of micronutrients. Folate, zinc, and antioxidants are required for the maintenance of normal sperm production and development. A folate deficiency could also lead to fragmentation of DNA and cause instability of chromosomes. Previous research proved there was a reduced spontaneous movement of sperm in people with a deficiency of these micronutrients. To assess the nature of DNA in the sperm from those with a micronutrient deficiency, this study was done on healthy, non-smoking men.
* The study population included 97 healthy males who were part of the Age and Genetic Damage in Sperm (AGES) study.
* Every participant was asked to complete a 100-item questionnaire, designed specifically to assess their micronutrient intake. Each also had to provide a semen sample.
* The sperm from the semen sample of each were analyzed and the results were statistically correlated with the participants’ micronutrient intake.
* The men were 91 percent Caucasian, 53 percent had post-graduate education,
and 57 percent took regular vitamin supplements.
* Those with a high folate intake had approximately 18 to 30 percent less frequency of sperm abnormalities.
* Those with a higher zinc intake had 39 percent lower frequency of a particular sperm abnormality than the low intake group. The high zinc intake group had 50 percent less frequency of the same sperm abnormality than the moderate intake group.
* The levels of vitamin C, E and other antioxidants had no correlation with the occurrence of sperm abnormalities.
The questionnaire used in this study to assess levels of micronutrients may not have been accurate with regard to blood concentrations. A causal relationship between folate intake and sperm abnormality was not possible to get in this study. Since many participants used supplemental vitamins, it was difficult to analyze micronutrient intake exclusively from diet. The authors suggest a larger study for a better analysis.
There was a significant association between folate intake and the sperm quality. The total folate intake was related to a reduction in sperm abnormalities. With this study being one of the first to examine the link between micronutrient levels and sperm abnormalities, larger studies are essential in the future. Even in those consuming 700 mg of folate on a daily basis, there was a lower incidence of sperm abnormalities. With the current recommended daily allowance of folate just 400 mg, there could be a higher incidence. This may indicate the need for an alteration in the current recommended allowance of folate. Increasing the folate requirement in those considering fatherhood could reduce the risk of genetic abnormalities in their offspring.
For More Information:
The Association of Folate, Zinc, and Antioxidant Intake with Sperm Aneuploidy in Healthy Non-Smoking Men
Human Reproduction, March 2008
By S. S. Young; B. Eskenazi; University of California, Berkeley
*FYI Living Lab Reports Are Summaries of the Original Research.