GMO potatoes: the risks to health
Dr Caius Rommens developed GMO potatoes, but subsequently renounced his work. He explains why we should be wary of the products he created
Dr Caius Rommens developed GMO potatoes for the Idaho-based agbiotech company Simplot. The chief genetic modification he introduced was to silence the potatoes' melanin (PPO) gene. This gene, when operative, causes potatoes to discolour when bruised. The GMO potatoes do not discolour when bruised. They have therefore been marketed as bruise-resistant and are being sold without GMO labels in the US and Canada under innocuous-sounding names like Innate, Hibernate, and White Russet.
After finding that “most GMO varieties were stunted, chlorotic, mutated, or sterile, and many of them died quickly, like prematurely-born babies”, Dr Rommens renounced his genetic engineering career and wrote a book about his experiences, Pandora’s Potatoes: The Worst GMOs, which is available from Amazon.
In an interview with GMWatch, Dr Rommens discussed the risks to health posed by the GMO potatoes he created.
GMW: In your article for Independent Science News, you mention that "The GMO potatoes are likely to accumulate at least two toxins that are absent in normal potatoes”. Can you tell us which toxins these are and what health problems they may cause or exacerbate?
About a year ago, I studied a research article written by some of my ex-colleagues. It provided evidence that silencing of a potato’s melanin (PPO) gene causes a massive increase in the levels of alpha-aminoadipate, also known as aminoadipic acid. It was a very casual observation, but normal potatoes already contain about 90 mg alpha-aminoadipate per kg (according to fooDB), which means that GM potatoes may have more alpha-aminoadipate than the GM corn variety LY038.
The story of LY038 corn can tell us much about the food safety risks of the GMO potatoes I developed. LY038 corn was engineered to contain high levels of the amino acid lysine and was intended as a nutritionally boosted feed for livestock. LY038 has high concentrations of alpha-aminoadipate, a known neurotoxin. Alpha-aminoadipate can be converted into advanced glycoxidation endproducts (AGEs) during cooking and processing. AGEs are strongly implicated in causing a variety of diet-related diseases, including diabetes, Alzheimer’s, and cancer.
LY038 corn was withdrawn from the European market by the developer company after regulators raised safety questions.
I also learned that damaged potato tissues accumulate the abnormal amino acid tyramine. These damaged tissues usually turn black so they can be identified and trimmed off by processors. However, in the case of GM potatoes, the bruises don’t discolour and thus are not removed during processing. This means that consumers may eat bruised tissues and be exposed to tyramine. The tyramine is metabolized in most people, but people who take MAOI antidepressants are unable to metabolize tyramine. The tyramine will accumulate in the blood and potentially cause hypertensive health issues.
Yet another ex-colleague had demonstrated that PPO-silencing causes an increase in the levels of chaconine-malonyl. Little is known about this compound, but it is a derivative of glycoalkaloid toxins. These can cause numerous health issues, including nausea, vomiting and neurological effects.
The most complex issue is that PPO-silencing also results in the concealment of various tuber infections. So consumers may eat potatoes that look perfectly healthy but actually contain fungal or bacterial pathogens. These pathogens often produce toxins and allergens.
Examples of fungal toxins that may accumulate in any concealed infections are Fumonisin, AAL-toxin, tentoxin, Rhizoctonia toxin, and Verticillium toxin. Additionally, there may be an accumulation of allergens such as Alt a 1.
GMW: Has any testing been done to ascertain whether the levels of these toxins are really higher in the GMO potatoes? It seems that at the very least, metabolomics and proteomics analysis should be carried out on the GMO potatoes to spot any biochemical changes that have occurred as a result of the GMO process.
My assessment of GMO potatoes is based on literature studies. I do not have the funds to carry out expensive tests to determine the range in levels of alpha-aminoadipate, tyramine, chaconine-malonyl, and so on. All I can do is to alert the public of potential issues and to urge companies to test their GM crops adequately.
By ‘adequately’, I mean that the potatoes used for testing should have been grown in the field rather than in greenhouses, and they should have been exposed to various stresses, such as infection, drought, heat, cold, and overwatering. I predict that the levels of tyramine, for instance, will be extremely variable. Small and unbruised GM potatoes will probably contain undetectable levels, but certain stressed and damaged GM potatoes may contain levels that are very high.
GMW: Why do you think that regulators in the US, Canada and Japan, which have approved these potatoes, are ignoring these aspects? Do they use any particular evidence to argue that they are not a problem, or do they simply not address them?
The standard tests needed to ensure regulatory approval are not set up to identify unintended effects. They are meant to confirm the safety of a GM crop, not to question their safety. None of the issues I address in my book were considered by the regulatory agencies.
GMW: Potatoes are vegetatively propagated, meaning that any unintended effects from the GMO process cannot be bred out by cross-breeding with non-GMO plants prior to marketing (though we do not imply that this procedure is necessarily effective). Does this mean that we consumers need to worry more about the food safety of GMO potatoes than about GM plants such as maize or soy, where the GMO version is backcrossed with non-GMO plants to at least attempt to breed out the unintended effects?
I agree with that statement. The genomes of the potatoes suffered numerous mutations during transformation and regeneration, and these mutations cannot be removed through breeding. The mutations will mostly compromise the agronomic performance of the GM crops, but it is possible they will also affect crop quality in unexpected ways.
GMW: You have criticised the current regulatory system for GMO crops, which relies on data generated by the company wishing to commercialise the crop. Which regulatory reforms for GMO crops would you like to see?
Yes, there cannot be any conflict of interest. Scientists are incredibly biased and narrow-minded. GM crops are their ‘babies’, and so it is almost impossible for them to be objective. We need independent scientists to study the safety of GM crops, and these scientists need to be trained in sensing where the unintended issues may be. We need ‘GM hackers’ (in the positive sense of the word). It is very difficult and will take much time.
GMW: Critics may claim that your book is just the unscientific ravings of a disgruntled ex-employee. They may add that if you had scientific doubts about the GMO potatoes, you should have published a peer-reviewed paper on the issues. How would you respond to these points?
It doesn’t matter if some individuals try to depict me as a deranged scientist. What matters is the message, not the messenger.
It was not my preference to publish this book without the involvement of my ex-employer. J.R. Simplot Company is a good company overall and I love the owner. It’s only the biotech group that needs feedback. About a year ago, I offered to work with this group on the issues I had identified by then, but there was no interest. And I understand this aversion to constructive feedback because I had the same aversion when I was still a genetic engineer. I did explain, though, that I would have to go public with my concerns. And I certainly hope that my book will be helpful to Simplot. Ideally, Simplot would set up a small committee of independent and open-minded scientists who would frequently review the work and plans of the biotech group.
There are many reasons why I wrote a book rather than published a peer-reviewed paper. One of these reasons is that it would cost me about half a million dollars to do all the studies required. I am part of the public now, and the public doesn’t have such funds. I wrote a book to reveal the hidden issues, and I hope that Simplot will agree to follow up. Another reason is that the peer review process doesn’t work. When I was still a genetic engineer, I spent a very large part of my time trying to confirm the work of colleagues – all of which was peer-reviewed – claiming to have discovered genes for higher yields, drought tolerance, cold tolerance, salt tolerance, higher levels of antioxidants, disease resistance, and so on. Of the many hundreds of presumed ‘key’ genes, only three or four genes were confirmed, mostly for late blight control.
The problem is that most scientists don’t take the time to carefully study their genes in the field. It is my honest opinion that 99% of the articles on GM crops are irreproducible and/or misleading and should be retracted.
GMW: Critics may dismiss your book and message on the basis that you retracted one of your papers. An article on RetractionWatch comments on the retraction. The article implies that you could have been guilty of misconduct and that you “made stuff up". The retraction notice explains that you asked the journal editor to retract the paper because genetic sequences that were stated in the paper to be native to potatoes turned out not to be – they were synthetic. While this doesn’t appear to equate to “making stuff up”, it does appear to be a mistake. Can you respond to RetractionWatch’s allegations and comment on any mistakes that led to your request to retract the paper?
We made a mistake in determining the sequence and origin of a tiny DNA fragment. The fragment was needed to transfer genes from bacteria to plant cells, but it was not transferred itself. The mistake happened very early on, a few months after we had opened the lab in 2001, when we tried to do too many things at the same time. We didn’t realize the mistake and published our first article in 2004. The mistake didn’t affect any of the approximately one hundred patents and other publications. I discovered the mistake in 2012 and took responsibility as director of research and development. We had an independent auditor for months checking hundreds of notebooks, but no other mistakes were identified.
Scientists make mistakes, and retractions are frowned upon, but I would be more concerned about scientists who never retract anything. I believe it is better to admit mistakes and move on than to cover them up.
GMW: Both scientist and lay critics of the GM food venture are regularly accused of being anti-science. How do you respond to that accusation?
When I think about scientists, I think about people who love to study—truly study—the natural world. But most people who call themselves ‘scientists’ are, in fact, numerologists who spend their days in offices, staring at computer screens. They are focused on generating and analyzing numbers. The numerologists say that a GM crop is safe because it has the same amount of amino acids and sugars as a normal crop. My concern about these numerologists is that they don’t love to study the natural world. They don’t have the interest to look at a GM crop and ask themselves the question: what is different about it? Even I had a hard time asking the real questions, and I think that my book is just the tip of an iceberg. Better, more open-minded scientists will hopefully step forward and discover issues I never even dreamt of.
GMW: You are now involved in non-GMO plant breeding. Critics of GM foods and crops are often told by plant genetic engineers that non-GMO plant breeding is slow and inefficient compared with GM. What is your response?
Breeding is much more fun than genetic engineering, and we can only succeed in making this world a happier place if we enjoy what we are doing. Nothing positive can be accomplished from a negative and biased work attitude. I am very hopeful about new methods meant to increase crop diversity, such as the methods that are being developed by Solynta. I am also excited about open-source initiatives, such as Bio-Impuls, to breed for better and more diverse varieties.