Excessive meat and dairy may harm sperm quality
NEW YORK (Reuters Health) - Men who eat lots of processed meat and full-fat dairy may have poorer quality sperm than those who eat more fruit, vegetables and low-fat diary, a small study suggests.
The study included 61 Spanish men visiting a fertility clinic. Half of the men had poor semen quality and generally had a higher intake of processed meat and high-fat dairy than did the 31men with normal sperm counts. The men with higher-quality sperm tended to consume more fruits, vegetables and skim milk.
The findings, reported in the journal Fertility and Sterility, do not prove that these foods contribute to or protect against sperm abnormalities.
But they do suggest that in addition to its numerous other health benefits, a well-balanced diet is important to fertility, lead researcher Dr. Jaime Mendiola, of Instituto Bernabeu in Alicante, Spain, told Reuters Health.
For example, Mendiola explained, the antioxidants found in fruits and vegetables may help protect sperm from damage. In a separate study, he and his colleagues found that men with normal sperm quality had a higher intake of certain antioxidants, like vitamin C and lycopene, than did men with sperm abnormalities.
Another factor may be that meat and high-fat foods may expose men to higher levels of substances known as xenobiotics -- including steroids and various chemicals in the environment that have estrogen-like effects, such as certain pesticides and PCBs. Xenobiotics tend to accumulate in high-fat foods, which in turn accumulate in men with high-fat diets.
Environmental contaminants can get into livestock through food and the water supply, Mendiola said. In addition, livestock in the U.S. are often given antibiotics and hormones for growth promotion.
Mendiola noted that the use of hormones has been banned in Europe since 1988, but the men in the current study were born in the 1970s and would have been exposed to hormones in meat and milk before the prohibition.
SOURCE: Fertility and Sterility, March 2009.