New Study Relying on People's Recall of Detailed Dietary Habits Serves Only to Distract From Importance of a Balanced DietMonday, March 23, 2009
Washington, DC – A new study in today’s Archives of Internal Medicine tries to predict the future risk of death by relying on notoriously unreliable self reporting about what was eaten in the preceding five years. This imprecise approach is like relying on consumers’ personal characterization of their driving habits in prior years in determining their likelihood of having an accident in the future.
“Meat products are part of a healthy, balanced diet and studies show they actually provide a sense of satisfaction and fullness that can help with weight control. Proper body weight contributes to good health overall,” said AMI Executive Vice President James H. Hodges. “Meat is an excellent source of zinc, iron, B12 and other essential vitamins and minerals. The U.S. Dietary Guidelines say to eat a balanced diet that includes lean meat. In this way, you derive a wide array of nutrients from many different sources. It’s the best return on a nutritional investment you can get.”
Hodges added, “Single studies cannot be used to draw major conclusions, yet that’s just what these authors seem to be doing by releasing this study with a major national press release.”
In this new study, researchers asked people to recall what they ate over the previous 12 months and to record it into a 35-page, detailed questionnaire. Notably, the front page of the questionnaire says “Answer each question as best you can. Estimate if you are not sure. A guess is better than leaving a blank.” After 10 years and after receiving questionnaires only at the outset, the five year mark and the 10 year mark, the researchers tried to correlate dietary factors with deaths.
“No doubt many participants guessed extensively in an effort to recall five years of habits and answer 35 pages of questions. Health conclusions and public policy recommendations should not be based on mere guesses,” Hodges said.
Further, many papers – including several recently published – reached far different conclusions about the role of meat in the diet which the authors did not acknowledge in their discussion of their own interpretations of the study data:
- A paper published in the March 11
American Journal of Clinical Nutrition
found that vegetarians had higher risk of colon
cancer than meat eaters.
- A Harvard study involving
725,000 people that examined red and processed
meat and colon cancer ─ the largest of
its kind on this topic ─ concluded that
there was no risk between the two (Cho,
Smith-Warner, et. al., American Association for
Cancer Research 2004
proceedings). Additionally, another
report from the same research group, failed to
find a protective effect of fruit and
vegetables against colorectal cancer in this
same population group. They
concluded, "Fruit and vegetable intakes
were not strongly associated with colon cancer
risk overall but may be associated with a lower
risk of distal colon cancer." (J Natl Cancer
- A new study which appears in this month’s peer-reviewed Journal of Nutrition carried out by the University of Illinois and Pennsylvania State University tested the effect of diet and found that a moderate-protein diet can have a significant positive effect on body composition as well as on cardio-vascular disease risk factors such as cholesterol. Subjects on the moderate-protein diet reported that they weren’t as interested in snacks or desserts, and they didn’t have food cravings.
The authors’ reference to a widely critiqued 2007 World Cancer Research Fund (WCRF) report and the suggestion that the latest study is consistent with it raises additional concerns.
The meat industry is not alone in its view of this report’s inherent problems. In 2008, Peter Boyle, Ph.D., Phillippe Autier, M.D., and Paolo Boffetta, M.D., Ph.D., of the United Nations’ International Agency for Cancer Research (IARC) wrote a highly critical editorial in the Annals of Oncology. In it, they said, "The substantial review of the evidence in the WCRF report demonstrates that there is no discernible association between many forms of cancer and specific dietary practices…the cupboard is remarkably bare... In view of the fragile grounds on which the conclusions of WCRF report on diet and cancer are based on, the information to the media should have been more cautious."
Also, in December 2008, IARC published a
major world cancer report (http://www.iarc.fr/),
noting that they had high “expectations that
epidemiological studies would discover the
dietary habits associated with increased or
decreased risk of cancer.” Those
expectations were not realized, IARC wrote in
the report: “Results from large
prospective cohort studies and randomized
trials provided evidence that apart from some
specific cancers (e.g., stomach cancer), diet
accounted for at best a minority of cancers.
In particular, intakes of fat, fruit and
vegetables and of meat were either not
associated or only slightly associated with
colorectal, breast and prostate cancer
Clearly there is a great deal of inconsistency in this type of research.
“Consumers should set this latest study of the week aside or they may experience another case of nutrition whiplash,” Hodges said.
For additional information visit http://www.meatsafety.org/. To view additional studies about the role of meat in the diet, visit http://www.meatsafety.org/ht/d/sp/i/41421/pid/41421. And for a short, educational video on processed meat, visit www.youtube.com/meatnewsnetwork.
share on facebook share on twitter