The study – published in Fertility and Sterility – examined the diet and sperm quality of 80 healthy men between the age of 22 and 80 years, finding that men older than 44 who consumed a ‘healthy intake of micronutrients’ had less damage to the DNA of sperm than those who did not.
Led by Dr Andy Wyrobek from the Lawrence Berkeley National Laboratory, USA, the research team found that men over 44 years of age who consumed the most vitamin C had 20% less sperm DNA damage compared to men older than 44 who consumed the least.
They revealed that the same was true for vitamin E, zinc, and folate.
"It appears that consuming more micronutrients such as vitamin C, E, folate and zinc helps turn back the clock for older men,” said Wyrobek.
“We found that men ... who consumed at least the recommended dietary allowance of certain micronutrients had sperm with a similar amount of DNA damage as the sperm of younger men," he explained.
"This means that men who are at increased risk of sperm DNA damage because of advancing age can do something about it. They can make sure they get enough vitamins and micronutrients in their diets or through supplements.”
Previous research conducted in Wyrobek's lab found that the older a man is, the more he's likely to have increased sperm DNA fragmentation, chromosomal rearrangements, and DNA strand damage. With more men than ever choosing to have children after the age of 35, the research team believes their work comes at an important time.
The research team analysed the sperm quality of 80 healthy male volunteers between the ages of 22 and 80 – with an average age of 44.
The men were recruited several years ago as part of the California Age and Genetic Effects on Sperm Study. Each man who participated in the study filled out a 100-item questionnaire that estimated their average daily vitamin intake, both from food and supplements.
In addition, their sperm DNA quality was assessed via a lab analysis in which a voltage gradient pulls broken DNA strands from intact strands within the sperm nucleus.
Each volunteer's intake of a micronutrient was classified as low, moderate, or high based on how they compared to other participants. The scientists then analyzed the data several ways and came up with the same result each time: a diet high in antioxidants and micronutrients may decrease the risk of producing sperm with DNA damage, especially in older men.
"The different response of the old and young men presents new opportunities for health care, especially for older men planning families," said Wyrobek.
However, he warned that more research is needed – adding that although the scientists found a clear link between higher vitamin intake and improved sperm DNA quality in older men, they don't know whether this link extends to male fertility and the health of offspring.
"Our research points to a need for future studies to determine whether increased antioxidant intake in older fathers will improve fertility, reduce risks of genetically defective pregnancies, and result in healthier children," he said.
"The research also raises a broader question beyond sperm DNA: How might lifestyle factors, including higher intakes of antioxidants and micronutrients, protect somatic as well as germ cells against age-related genomic damage?"
Source: Fertility and Sterility
Published online ahead of print, doi: 10.1016/j.fertnstert.2012.07.1126
“Micronutrients intake is associated with improved sperm DNA quality in older men”
Authors: Thomas E. Schmid, Brenda Eskenazi, Francesco Marchetti, Suzanne Young, et al