Wading into the debate about GMO safety requires the reader to either slog through hundreds of studies, refutations, and meta-analyses, or throw one’s hands in the air and default to one’s original belief about the subject. Studies abound, but in many cases there is a conflict of interest; a 2011 examination of 94 studies found that while there was no correlation between industry funding and a favorable study outcome, there was a very significant correlation between a favorable outcome and one or more of the study authors having a conflict of interest (p < .001, for the statisticians out there).
Additionally, nearly half of the studies did not disclose their source of funding. This professional conflict of interest has been documented by other researchers as being strongly related to positive outcomes of biomedical and nutritional studies. On the other hand, only a total of 12 of the studies did have a negative outcome. These negative outcomes have included a list of dramatic health problems in the test animals: stomach lesions, tumors, reproductive issues, and others.
But in many cases there is scientific debate over the studies. Were there enough test subjects? Was there a statistical difference between the health effects on the control group and the animals fed the GMO crop? Some scientists express concerns that the genes in GMOs, some of which are from organisms that a human would never eat (such as the Bt bacteria), may cause an increase in food allergies. Other authors note that livestock have been fed a GMO diet of corn and soy for almost 20 years and there has been no corresponding surge in health problems among livestock. Some genetic modification is doubtless completely innocuous; more precise modifications for flavor or other characteristics do exist, although they are far outnumbered by modifications for pesticide or disease resistance.
Lack of Long-Term Studies
The Public Health Association of Australia and the British Medical Association express concerns that the safety of GMOs has not been satisfactorily demonstrated by long-term studies, with PHAA adding that many animal feeding studies have lasted for only a few weeks, and some have only evaluated animal production characteristics such as weight or milk production. Pro-GMO authors often paint detractors as anti-progress nuts whose paranoia and acceptance of “bad science” reaches a religious fervor. While this is true of some, the anti-science label is used too widely.
This, unlike the debate over vaccines or global warming, is one where the dangers of taking a cautious approach are nil: it’s a case of “better safe than sorry” with no downside for the “safe” choice. No one will be worse off than they were before the advent of GMOs if they simply abstain. Of course, without a labeling law, abstaining isn’t easy.