GM Crops and Food: Good for Your Health?

THE GM DEBATE
A series of background briefings to help you get informed and involved as the Government gears up to make its decision about the future of GM in the UK

GM Crops and Food:
Good for Your Health?

I

n order to produce a genetically modified (GM) crop, genes are transferred from bacteria, viruses and plants to change the crop in certain ways – to make it resistant to insects or disease, or tolerant to weedkiller, for example. But is GM food safe to eat? The decision on whether we grow GM crops in the UK will influence the extent to which non-GM food is available, so considering GM food safety is an important part of the debate.

There are several ways that GM food could be harmful:

·      The genetic modification itself may make the plant toxic when eaten.

·      The new GM characteristic may cause allergies.

·      If antibiotic resistance genes are used, they may increase problems with drug resistant diseases.

·      The GM process may have unintended effects on the plant, which may affect food safety.

Are our testing systems and safety monitoring systems good enough to allow GM crops to be grown here? Some argue that GM foods are tested more thoroughly than any other foods, while others believe that we have not tested them enough so would not know if there are problems. Although GM foods have been eaten in some countries for six years, there has been no monitoring so hard evidence about their safety is in short supply.

Toxicity – When a crop is changed to make it resistant to insects or tolerant of weedkillers, it has to make new compounds to carry out these functions. If people have not eaten such compounds before, they will need to be safety tested. Some toxicity testing is carried out using laboratory animals, which may detect very rapid effects but may not identify longer-term, more subtle health effects.

Allergies – The new compounds produced in the GM food may cause an allergic reaction. Food allergies are on the increase as we eat more varied diets with new ingredients. It will be possible to test if the GM genes come from peanuts, for example, which are known to cause allergies in some people, but with new sources it will be much harder. When a new food is introduced, it takes 5-6 years before allergies are recognised.

Antibiotic resistance - Antibiotic resistance genes are used as ‘markers’ in GM crops to indicate whether the genetic modification has been successful. The GM process is inefficient and only a small number of cells incorporate the foreign genes. Therefore, an antibiotic resistance gene is included and, if the genetic modification is successful, the plant cell will grow in the presence of the antibiotic - if not, it will die. If these genes are transferred to disease-causing organisms, they may compromise antibiotic treatment. The antibiotic marker genes have no function in the plant and could be removed, but this costs more. The British Medical Association has called for a ban on the use of antibiotic resistance marker genes.

Unintended effects – GM is not a precise technique. There is no control over where genes are inserted among the plant’s own genes. Many copies or fragments of genes can be included and the gene may even be inserted backwards. There is plenty of potential for unexpected outcomes if normal genes are disrupted or the foreign gene does not function properly. These may affect the chemical composition of the crop and the safety of the food derived from it. Until recently, GM food safety testing ignored the potential for unintended effects, and techniques to screen GM foods for ‘surprise’ effects are still in the development stage.

Despite the risks associated with GM foods, there could also be benefits which might outweigh them. They could, for instance, bring healthier foods or help people in developing countries who are malnourished. How likely are these potential benefits?

GM food with health benefits?

GM crops with increased levels of vitamins and chemicals that may help protect against heart disease and cancer are being developed. These kinds of foods will be

expensive and marketed as ‘functional foods’. However, scientists say the best diet for a healthy life is one which includes plenty of fresh fruit and vegetables. Some research shows that, whilst a certain intake of vitamins is essential, they can be harmful at higher levels. GM ‘fortified’ foods may therefore be harmful and not beneficial to health.

Solving malnutrition in developing countries?

Many thousands of children go blind or die each year in developing countries because of a lack of vitamin A. The World Health Organisation’s plan to eradicate vitamin A deficiency by 2000 failed because the political will to supply the necessary supplements or mixed diet did not exist. The biotechnology industry has produced GM rice with extra pro-vitamin A, which is converted into vitamin A in the body. They argue that this ‘golden rice’ will help prevent deaths due to lack of vitamin A. The GM rice has not yet been proven to work and some people feel it is being used to blackmail people to accept GM foods when it would be quite easy to solve the problem in other ways.

 

Debating matters

·      Should all GM foods be labelled? – If GM foods were labelled, this could help people decide whether they wanted to take the risks of eating them. Currently, only ingredients which contain more than 1% foreign DNA or protein are labelled. Derivatives which have no foreign DNA or protein, such as the oil from GM soybeans, are not labelled. The UK Government is opposing European plans for more comprehensive labelling of GM foods, saying costs would be too high and people could cheat. Should we grow and import GM foods without full GM food labelling?

·      Monitoring for health effects? - There has been no monitoring for health effects of eating GM foods in North America. Should there be a requirement for health monitoring if we go ahead with GM crops in Britain?

·      Systems to trace GM foods? – Tracing where food is produced and distributed can help to identify and track health problems. After BSE and Foot and Mouth Disease, systems have been put in place to monitor the movements of farm animals in Britain. Europe has proposed similar plans for GM foods but the UK Government says they will not work. Should tracking GM foods be a requirement or will the costs be too great?

·      Providing better diets for poor people? – The second generation of GM crops may have extra vitamins and minerals. Is this the best way to deal with malnutrition in developing countries and tackle obesity in the developed world?