GMO Myths and Truths

3.3 Myth: Those who claim that GM foods are unsafe are being
selective with the data, since many other studies show safety
Truth: Studies that claim safety for GM crops are more likely to
be industry-linked and therefore biased
“In a study involving 94 articles selected
through objective criteria, it was found
that the existence of either financial or
professional conflict of interest was associated
[with] study outcomes that cast genetically
modified products in a favourable light.”
– Diels J, et al. Association of financial or
professional conflict of interest to research
outcomes on health risks or nutritional
assessment studies of genetically modified
products. Food Policy. 2011; 36: 197–203
When it comes to hazardous products, the bias
of industry-sponsored or industry-linked studies
is well documented. Every time industry-linked
studies are compared with studies on the same
product from the independent (non-industrylinked)
scientific literature, the same verdict is
reached: industry studies are biased towards
conclusions of safety for the product.
The best known example is tobacco industry
studies, which successfully delayed regulation for
decades by manufacturing doubt and controversy
about the negative health effects of smoking
and passive smoking. 53 More recently, studies
sponsored by the pharmaceutical and mobile
phone industry have been shown to be more likely
to portray their products in a favourable light than
non-industry-funded studies. 54,55,56
The case of GM crops is no different. Reviews
of the scientific literature on the health risks of
GM foods demonstrate that the studies that show
safety are more likely to be industry-linked and are
therefore inherently biased:
● A review of 94 published studies on health
risks and nutritional value of GM crops found
that they were much more likely to reach
favourable 53 conclusions when the authors
were affiliated with the GM industry than
when the authors had no industry affiliation.
In the studies where there was such a conflict
of interest, 100% (41 out of 41) reached a
favourable conclusion on GMO safety. 57
● A literature review of GM food safety studies
found that most studies concluding that GM
foods are as nutritious and safe as non-GM
counterparts were performed by the developer
companies or associates. 58
In spite of the fact that industry-linked studies
have been shown to be biased, approvals for GM
crops are based solely on such industry studies.
Another tactic used by GM proponents is to
point to lists of studies which they say show that
GM foods are safe, but which actually show nothing
of the sort. An example is on the GMO Pundit blog
site, which claims that the over 400 cited studies
“document the general safety and nutritional
wholesomeness of GM foods and feeds.” 59
But closer examination reveals:
● Most of the studies cited are not safety studies
on GM foods. In other words, they are not
animal feeding studies that look for health
effects in animals fed GM foods. Some are
compositional studies that compare the levels of
certain major nutrients, such as fat or protein, in
a GM crop with levels in a non-GM crop. Others
are feed conversion studies that measure how
efficiently a livestock animal converts GM feed
into a food product, such as meat or milk.
● Many of the studies, on examination of the
actual data, show problems with GM foods. These
include unintended differences in a GM food
compared with the non-GM counterpart and
harmful effects in animal feeding trials. In fact,
some of these studies are cited in this report as
evidence that GM foods are not safe. Readers are
encouraged to examine the original studies, where
available, and form their own conclusions.
In contrast with these lists on GM proponents’
websites, the two peer-reviewed literature reviews
cited above identified and evaluated the studies
that specifically examine the food safety and
nutritional value of GM foods. Their conclusions
were clear: industry-linked studies are more likely
to conclude safety, whereas independent studies
are more likely to find problems. 57,58
GMO Myths and Truths 46