The American Meat Institute Foundation said cured meats
are a safe and healthy part of a balanced diet, responding to a recent
Harvard School of Public Health Study that concluded cured meats increase the
risk of leukemia in children and young adults.
The study, published in the BioMed
Central Cancer journal, found an association between eating smoked or
cured meat and fish more than once per week and an increased risk of acute
leukemia due to exposure to nitrites and nitrosamines. Moreover, it found
that people who consumed vegetables and soybean curd regularly with cured
meats demonstrated a reduced risk for leukemia.
Conducted in Taiwan,
the population-based case-control study investigated the dietary habits of
515 people who ranged in age from 2 to 20 years and were recruited between
1997 and 2005. Dietary data were obtained from a questionnaire.
AMI warned that, "nutrition decisions should be based on the total body
of evidence — not on single studies that stand in contrast to U.S. Dietary
Guidelines and to other studies in published literature."
AMIF President James H. Hodges noted that epidemiological studies do not
establish cause and effect; rather, they allow researchers to identify
associations that might warrant further study. He took issue with the
researchers lumping cured meats with smoked fish, noting that fish consumed
by the subjects in the study — Chinese salted fish — is classified by the
International Agency for Research on Cancer as a class I carcinogen.
"Taking this approach and combining cured meats and salted fish as a
single category is like studying someone who ate arsenic and broccoli and
blaming a resulting illness equally on the two," Hodges said in a
statement, noting a University of California-Berkely
study in June 2004, published in the American Journal of Epidemiology,
concluded "consumption of hot dogs/lunch meats was not associated with
the risk of childhood leukemia."
Hodges also raises the issue of epidemiological studies estimating the
strength of associations by using "odds ratios." An odds ratio of
1.0 means a particular variable was neutral in its effect. An odds ratio
below 1.0 suggests a variable may protect against a disease outcome. An odds
ratio above 1.0 suggests a factor might need to be studied more closely.
The Harvard study's main claim had an odds ratio of 1.74. "A general
rule of thumb within the field of epidemiology holds that an odds ratio below
2.0 is not viewed as a strong relationship and may actually have occurred by
chance," AMIF said. "Epidemiological studies though to have truly
uncovered significant associations and cause for concern — like studies
looking at tobacco and lung cancer — found odds ratios in the 10-25
Another possible flaw was the study's "case-control" approach.
People were asked to recall what they had eaten, how much they had exercised
and other lifestyle choices years later. AMIF said this "approach is
plagued by 'recall bias' in which people recall past events
To view the study in its entirety, click here.