I was asked on Friday 12th Feb to write a piece to balance the widespread public alarm about GM foods and GM crops. My views were partially summarized in the Sunday Times editorial on 14th Feb. On Monday 15th I became the story. Heres what I wrote.
What are people to make of the latest furore about genetically modified (GM) crops and GM food? This week renewed concern was expressed about an incident in 1989 in the US in which 37 people died as a consequence of consuming tryptophan supplements that derived from GM bacteria. The damage seems to have been due to a faulty manufacturing process, but GM was made the scapegoat. And then we have the case of Dr Pusztai. Despite having worked with GM plants for the last 16 years, I share the puzzlement of many about what to make of the latest news from the Rowett. Last August we heard that GM potatoes that had been engineered for enhanced insect resistance through expression of a lectin, were not only bad for insects, but also for rats, and by implication for humans. Two days later we heard that Dr Pusztai, the source of this work and a distinguished expert on lectins, had been dismissed because the work did not involve GM potatoes at all, but rather an addition of lectin to unmodified potato meal. Now we hear that a press conference of scientists (not the usual generic) backs Dr Pusztai and regards his concerns about GM foods as valid.
As a scientist myself I can only say "show me the data". Grandstanding does not resolve scientific questions. But I would not be in the least surprised to discover that modifying potatoes so that they produce an additional lectin renders them damaging to health, if served uncooked. Lectins are found in many plants- for example runner beans- and are known to be potentially toxic, but like other proteins, most lectins are inactivated by cooking. Was the genetically or lectin- modified potato cooked? We have not been told. Dr Pusztai's supporter's experiments have been reported to suggest that the GM potatoes are even more hazardous than would have been expected if they contained an added lectin. This seems intrinsically implausible (and difficult to measure; what was the control?). However, decades ago, plant breeding produced some potato varieties that had to be withdrawn because they contained high levels of dangerous alkaloids. Could this problem have affected the particular GM line used in Dr Pusztai's experiments? It's possible, but would not prove that all GM potato lines with this gene would have this problem. As usual with GM, the media have shed so much more heat than light that we are still in the dark.
The Rowett Institute needs to carefully examine whether Dr Pusztai was fairly treated, and if he was, should explain itself better. However, for public policy on GM technology, the results of Dr Pusztai's experiments are irrelevant to the question of whether a blanket moratorium on GM crops and food is needed. The GM lectin-containing potatoes may be weighed in the balance and found wanting. Or they may not. If they are unsafe to eat, they will not be approved for sale. Either way, the system works. In a similar story in the US, Pioneer Hybrid developed soybeans that had been engineered to express a brazil nut protein to improve nutritional quality. However, this protein is a potent allergen whether it is made in brazil nuts or in soybeans. During trials, and well before it entered the human food chain, the foolishness of delivering a serious allergen into the commodity markets was realized and the project was terminated. These examples do not imply that every GMproduct is dangerous and should be banned; each new proposal should be (and is being) examined on a case by case basis.
GM technology is powerful, and can be used wisely or unwisely. In this it resembles chemistry, another powerful and potentially dangerous technology, which can be used to make nerve gas and explosives, as well as aspirin and Teflon. For both chemistry and GM, society needs to take a keen interest in how these technologies are used and what they are used for. There needs to be confidence in the process by which potential hazards to human health and to the environment are assessed. Has the industry earned this confidence yet?
In the United States, 30% of soybeans and maize have been planted to GM varieties. Confidence in the regulatory authorities is much greater in the US (where food and agriculture and regulated by the FDA and the USDA respectively) than in the UK, where both are regulated by MAFF. Here the BSE crisis has undermined still further consumer confidence in MAFF, which was seen to have valued the interests of farmers above those of consumers. With the current climate of concern about GM crops it is crucial that an independent Food Standards Agency is up and running in the UK as soon as possible.
How have GM foods been regulated ? Much has been made of the fact that experimental evidence regarding their safety has been provided to the FDA by the companies that made them, which till now has primarily been Monsanto. Cubic feet of paper have been used to provide data to the agencies attesting to the safety of these GM products. Some suggest that because these data are provided by the companies, it cannot be trusted. If I could imagine plausible routes by which the GM maize and soy products on the commodity markets could be hazardous to my (and my children's) health, I might be more concerned. I cannot. They have been subjected to unprecedented scrutiny and have been found to be perfectly safe, both by US and UK regulatory authorities. Moreover, it is not in Monsanto's interests to take any risk of poisoning the litigious residents of the US (including this week, the Leader of the Opposition) and most of the rest of the world.
In fact, GM maize is probably safer to eat than non GM maize. A significant food hazard in grains is provided by the presence of poisonous and carcinogenic mycotoxins produced by certain fungal infections. The GM maize makes BT, another insecticidal protein (but not a lectin). This GM maize resists corn earworm and has lower levels of mycotoxin, because damage caused by the earworm on non GM maize provides many extra entry points for the fungus. Yields of BT GM maize are up to 15% higher than non BT maize, which reduces the cost of production. The BT GM maize needs less insecticide application and will carry less insecticide residues than non GM maize.
Many other examples of the benefits of GM are appearing. Scientists in the US have isolated a pepper gene for bacterial disease resistance. On insertion of this gene into tomato, which is badly affected by the same disease, the gene again confers resistance. Other US workers have engineered plants to make substantially higher levels of vitamin E, a potent antioxidant and probable anticarcinogen. GM modification for improved disease resistance and enhanced nutritional quality are just two of the many valuable traits that will in time render unassailable the proposition that this technology is broadly beneficial for consumers and for the environment and certainly not dangerous.
Why have GM crops provoked so much more concern than other new agricultural technology, such as deploying a new fungicide or insecticide? They have perhaps become a lightning rod for a broad public disquiet about the impact of of agriculture on the environment, food safety, animal welfare, the growing power of big agrichemical companies that have reinvented themselves as life science companies, and a sense that you need a degree in biochemistry to be able to make informed choices in the supermarket. While researchers may be dismayed that their best efforts are unfairly and inaccurately caricatured, the public has a right to insist that modified food is not only as safe as the food they have been eating, but offers genuine benefits. The public is not convinced of the benefits of herbicide resistance, and English Nature has expressed legitimate concern about the possible adverse consequences for wildlife if the technology is carelessly deployed in the UK. 80% of UK land is farmed; in the US this figure is only 35%, so our wildlife is more dependent on our farming practice. A delay to establish best practice before unrestricted commercial planting seems advisable. I welcome the Government's move to extend the remit of ACRE (which regulates planting of GM crops) to include environmental impact. Likewise, even though GM maize and soy is chemically indistinguishable from non GM, labelling is clearly demanded by the public. In the future it can be anticipated there will be a non GM section of the store, probably next to the organic section, and most produts will be "GM maybe".
This technology is in its infancy but is already delivering benefits. Insecticide use in the US has been dramatically reduced by deployment of BT cotton. The future benefits (for consumers and the environment) will be enormous and the best is yet to come. In the meantime, let's have more information and less rhetoric.
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