Correlation of high beef consumption during pregnancy and low sperm
count is sons with greater fertility problems.
May be due to anabolic steroids used in USA to fatten cattle $$$$$$$$$$
Small effect, but significant.
USDA may need to reexamine allowed limits on injected hormones in meats.
Schettler noted that there was room for a lot of inaccuracies in the
mother's recall of her diet [two decades earlier], "but what that tends
to do is bias the study toward not finding anything.
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Mom's beef puts son's sperm count at stake
By Thomas H. Maugh II, LA Times Staff Writer
March 28, 2007
'Tip of the iceberg'
Men whose mothers ate a lot of beef during their pregnancy have a sperm
count about 25% below normal and three times the normal risk of
fertility problems, researchers reported Tuesday.
The problem may be due to anabolic steroids used in the United States to
fatten the cattle, Dr. Shanna H. Swan of the University of Rochester
Medical Center reported in the journal Human Reproduction. It could also
be due to pesticides and other environmental contaminants, she added.
If the sperm deficit is related to the hormones in beef, Swan's findings
may be "just the tip of the iceberg," wrote biologist Frederick vom Saal
of the University of Missouri-Columbia in an editorial accompanying the
paper.
In daughters of the beef-eaters, those same hormones could alter the
incidence of polycystic ovarian syndrome, the age of puberty and the
postnatal growth rate, he said.
"It's a small effect, but it is a significant effect," said Dr. Ted
Schettler, an environmental health specialist at the Institute for
Global Communications in San Francisco. "It's not surprising. The more
you look at dietary factors, the more you turn up interesting
information about how diet during pregnancy affects lots of aspects of
human health."
Six growth-promoting hormones are routinely used in cattle production in
the United States and Canada: the natural steroids estradiol,
testosterone and progesterone, and the synthetic hormones zeranol,
trenbolone acetate and melengestrol acetate. At slaughter, not all of
these hormones have been metabolized.
Diethyl stilbestrol was also used in this country from 1954 to 1979,
when it was banned after tests showed that minks fed chicken waste
containing DES became infertile.
The Food and Drug Administration limits how much hormone residue is
permissible in beef. Those limits may need to be reexamined if Swan's
findings can be confirmed, Vom Saal said.
The use of these hormones in beef was banned in Europe in 1988, and the
United States has disputed the EU's attempts to ban imports of U.S. beef
containing hormones.
Studies in rodents have shown that even a trace of estrogen in the
uterus from food can affect an offspring's sperm count, but no one has
previously tried to study the question in humans.
Swan and her colleagues studied 387 partners of pregnant women in five
U.S. cities, including Los Angeles. Each man provided a sperm sample and
his mother filled out a questionnaire about her food consumption during
pregnancy.
Swan concedes that women may have difficulty recalling their diets more
than two decades earlier, but pregnancy may be an exception. "When you
are pregnant, you are very aware of what you eat," she said.
The mothers were asked how often they ate beef and other meats. On
average, they ate beef about 4– times per week, and other meats much
less frequently.
They found that, in general, the more beef a woman ate, the lower her
son's sperm count. For women who ate beef at least seven times a week,
the son's sperm averaged 24.3% below normal. And even though those sons
produced a pregnancy, they were three times as likely to have consulted
a fertility doctor.
The researchers found no link to the mother's smoking, employment
outside the home or the number of children she had. There was not enough
data on other meats to reveal a potential association.
Schettler noted that there was room for a lot of inaccuracies in the
mother's recall of her diet, "but what that tends to do is bias the
study toward not finding anything. So the fact that she found [a
relationship] was kind of a surprise to me."
The finding applies only to North American women, Swan said, because
beef-producing practices vary widely elsewhere.
Swan emphasized that the study needs to be confirmed, adding that it is
too soon to recommend that pregnant women not eat beef. But if a
pregnant woman wants to be cautious, she said, she could switch to
organic beef or other high-protein food.