Last updated March 6, 2017 at 3:16 pm
Science Update is a monthly written series from Dr Paul Willis tackling some of the controversial topics in the public and aims to provide the current research behind these subjects.
Genetically Modified Organisms (or GMOs) have been incorporated into agriculture around the world and they have been available for almost 3 decades but there is still a popular debate concerning this technology and whether or not it is safe to eat GMOs. So what is the science behind the issue of GMO safety? This Science Update focusses specifically on the issue of GMO safety in the human food chain while questions of GMO safety in the environment will be the subject of a future Science Update.
The evidence for GMO Safety
The science is squarely behind the safety of consuming GMOs. There is good, scientific evidence presented in peer-reviewed sources that attests to the safety of GMOs as part of the human food chain and that GMOs in agriculture may actually provide environmental benefits. An extensive review by the National Academies of Sciences, Engineering, and Medicine earlier this year of many issues arising around GMO technologies failed to find any valid studies that upheld proposed dangers to human health from eating GMO crops.
A poll conducted by the Pew Research Centre in association with the American Association for the Advancement of Science (AAAS) early in 2015 found 89% of scientists thought that GMOs were safe for human consumption.
While appeals to authority must be carefully assessed, when 119 Nobel Laureates and 6151 scientists signed a letter criticising the environmental group Greenpeace for misrepresenting the science of GMOs and the safety concerns surrounding them, this could be taken as an influential endorsement of GMO safety. This story was reported by The Washington Post.
The evidence against GMO Safety
The scientific case against GMO safety is thin with many examples being withdrawn or discredited.
Environmental groups such as Greenpeace offer several arguments against GMO technology, mostly on environmental grounds but with some claims against GMO safety for consumption. Among these claims are references to an Austrian study that found mice fed GMO maize have fewer offspring. However that study has subsequently been withdrawn because of methodological problems.
Other frequently cited papers reporting problems with GMO safety include this one claiming a protein found in some GMOs is also found in maternal and foetal blood. That study has also been discredited as methodologically flawed. Furthermore, a list of 10 studies frequently cited by anti-GMO activists have all been discredited.
Science v Popular Opinion
There is a big gap between the acceptance by science for GMO safety and the public opinion that GMOs are unsafe to eat.
The same poll of scientists that found 89% of scientists thought that GMOs were safe for human consumption also found that 57% of Americans think that GMO foods are unsafe and 67% of them do not trust scientists.
So why is there a difference between the scientific evidence for the safety of GMOs and the popular perception that they are unsafe? There could be many factors including a public intuition concerning the dangers of tampering with DNA, a sense of disgust at ingesting something novel or a fear of contamination of our food source. In the case of environmental groups, opposition to GMO technology appears to be part of a wider attack on agribusinesses such as Monsanto and Syngenia.
The essence of good science is the willingness to change your mind in the face of new evidence. A good example of this ethos in practice occurred last year when Bill Nye, the popular US science communicator known as The Science Guy, publicly switched his stance on GMO safety. Previously he had written extensive articles arguing that GMOs were unsafe for human consumption and that there were potentially damaging environmental effects from the spread of GMOs into modern agriculture. But, after extensive discussions with geneticists working in Monsanto, he changed his opinion to recognising that GMOs offer no increased risks to consumers than the consumption of their non-GMO equivalents.
Is this a trend we’re seeing among a wider audience? A public debate held in the US in 2014 saw a significant switch in the audience from uncertain about GMO safety to accepting that GMOs are safe. Back home, Australian attitudes do seem to be shifting as well.
There is a large body of research that demonstrates GMOs are safe to eat by humans. Conversely, there is no credible research demonstrating harmful effects for humans eating GMOs. It’s clear there’s a big difference between the scientific position on GMO safety and public opinion on this issue. With strong arguments that the popular opposition to GMO foods is not a matter of science, perhaps the approach to educating the public needs to change. For now, with greater awareness and understanding of the science, this gap is narrowing.