Consumers were frightened this week by
media reports about a new study claiming
to link mothers' consumption of beef with
reduced sperm counts in their sons ( "Sperm
Count Low if Mom Ate Beef, Study Finds" ).
But the study amounts to nothing more than
a transparent effort to resurrect an already
debunked 1990s-era health scare with appalling
science and sensational headlines.
From "Mom's beef puts son's sperm
count at stake" (Los Angeles Times)
to "Meaty momma's boys lose" (Edmonton
Sun, Canada) to "Sunday roasts could
have hit male fertility" (Daily Mail,
UK), gullible media around the world once
again fell for science-by-press-release
committed by longtime environmental activist-researchers.
The supposed findings of the study were
that "men whose mothers had eaten
more than seven beef meals a week had a
sperm concentration that was over 24 percent
lower than in men whose mothers ate less
beef "and that three times more sons
of high-beef consumers had a sperm concentration
that would be classified as sub-fertile,
according to World Health Organization
standards, in comparison to men whose mothers
ate less beef."
But for anyone who makes the effort to
look past the press releases touting these
findings and to examine the study that
supposedly backs them up, these findings
fall apart as easily as slow-cooked pot
roast.
First, the researchers approached the question
of what caused the reduced sperm counts
exactly backwards. Rather than investigating
all possible causes and eliminating those
for which there are no supporting evidence,
the researchers, according to their own
admission, set out to link maternal beef
consumption with fertility problems while
ignoring other possible causes.
There are myriad causes of infertility.
Focusing on a novel one that might make
for good headlines -- while overlooking
established, but less newsworthy, causes
-- simply does not constitute bona fide
scientific investigation.
Then, of course, none of the men studied
seemed to have fertility problems in the
first place. In fact, the men had all fathered
children. But they were nonetheless targeted
by the researchers because "[their]
rate of consulting a doctor in the past
for possible infertility was significantly
higher."
Simply consulting a fertility specialist,
however, does not necessarily indicate
that a man has fertility problems.
The researchers' hypothesis is not that
beef itself causes infertility, but rather
that the hormone-like medicines and chemicals
to which cattle may be exposed are at fault.
But even if it were true, for the sake
of argument, that hormone-like chemicals
were linked with male infertility, the
researchers would still be obligated to
rule out other potential exposures to these
chemicals, such as through other foods
or occupational exposures in both the mothers
and sons, before blaming beef consumption
by mothers.
But the study gets worse.
Although the researchers tout a study size
of 387 subjects, only 51 of the sons had
mothers who allegedly ate beef more than
seven times per week when they were pregnant.
So the researchers drew an awfully sweeping
conclusion from a minuscule study population.
Moreover, the data on mothers' beef consumption
during 1949 to 1983 were collected by surveying
the mothers during 1999 to 2005, as long
as 50 years after they were pregnant.
Such self-reported dietary data were not
verified by the researchers and are subject
to phenomena known in scientific circles
as "recall bias" (memory-impaired
responses) or "response bias" (intentionally
incorrect responses to, say, avoid embarrassing
answers). No one really knows what or how
much these women actually ate.
It's also not necessarily true that more
frequent beef consumption is greater beef
consumption. Someone who consumes four
8-ounce portions of meat per week consumes
14 percent more beef than someone who consumes
a 4-ounce portion every day -- yet, in
this study, the everyday-meat eater is
assumed to be the greater consumer of beef.
Although the researchers say in their
media release, "We don't have enough information
yet to make any recommendations, and this
is not what this study was designed to
do," they then proceed to make dietary
recommendations including eating only organic
beef and generally reducing beef consumption.
This study is about causing alarm, not
about sound scientific research.
So just who are these researchers and
what's their real beef?
The University of Rochester's Shanna
Swan and Danish researcher Niels Skakkebaek
are well-known to followers of the now-defunct
1990s controversy over hormone-like chemicals
in the environment, so-called "endocrine
disrupters" or "environmental
estrogens."
Swan, Skakkebaek and others have been
trying to scare people that man-made
chemicals in the environment and food
are reducing fertility, particularly
sperm counts. Swan has published 15 related
studies since 1997 and Skakkebaek has
more than 80 related citations in the
scientific literature dating back to
1992.
Despite tremendous media attention, the
science of Swan and Skakkebaek has never
been particularly persuasive. A National
Academy of Sciences committee concluded
in 1999 that, "Given the evidence
to date, increases in the incidence of
male reproductive disorders in humans --
cannot be linked to exposures to [hormonally-active
agents] found in the environment."
And since there do not appear to be any
sort of worldwide fertility problems
that cannot be explained by other causes,
it's no wonder that the endocrine disrupter
scare never gained traction.
In addition to the news media's predilection
for scary health stories, who, after
all, could pass up a story about hamburgers
as intergenerational contraceptives?
It unfortunately suffers from an abysmal
institutional memory, particularly when
it comes to science.
So Swan and Skakkebaek can always count
on gullible reporters parroting their "findings" as
if they were novel, credible and important,
rather than what they really are: stale,
unbelievable and meaningless.
Steven Milloy publishes JunkScience.com
and CSRWatch.com. He is a junk science
expert, an advocate of free enterprise
and an adjunct scholar at the Competitive
Enterprise Institute. He can be reached
at stevenmilloy@yahoo.com. |
