Need another reason to dodge Frankenfoods? Genetically modified foods are significantly more likely to trigger an allergic response, says Teresa Mitchell-Paterson.
The overarching concern about genetically modified (GM) crops is that the imported genes produce a protein that has never previously been part of the human food supply – and we don’t know what the long-term impacts may be. One possible effect may be to trigger an immune (allergic) response, which is exactly what occurred during the mid-90s – as evidenced in blood tests – when a gene from the Brazil nut was added to the soybean. This was one GM crop that never made it to market!
Scientists developing GM varieties are obliged to compare the amino acid sequences of a new protein with a database of proteins proven to cause allergies. If the GM protein’s sequences are identical to sequences in the allergen database, WHO and UN FAO criteria recommend the GM crop should not be commercialised, or that further testing should be undertaken.
The problem with soy
One of the world’s major GM crops is soy, genetically modified to withstand herbicide application. The US is the world’s largest soy producer, with 93 percent being GM. Unfortunately, sections of the protein these soybeans produce match known allergens, but as the WHO-FAO amino-acid comparison criteria were not in place when the crop was introduced, no additional testing took place.
In 1999, shortly after imported GM soy was introduced to the UK, soy allergies in that country jumped 50 percent over the previous year. The GM protein responsible for soy’s herbicide resistance doesn’t have a history for safe use in humans and hasn’t been extensively tested. However, studies on mice fed GM soy reveal reduced levels of pancreatic enzymes. If this translates to humans, reduced pancreatic enzymes means a lessened capacity to break down sugar.
This is totally anecdotal, but in clinic I have repeatedly noticed that people who consume large amounts of soy tend to put on weight – and I wonder whether the sugar is turning to fat cells because it’s not being properly metabolised. Suppressed digestive enzymes also mean food remains in the gut for longer – and these mice were experiencing strong intolerance reactions in the gut.
Some years ago, corn was engineered to include a gene from Bacillus thuringiensis (Bt), a soil bacterium that naturally produces a toxin that acts as a pesticide. Despite being approved only for stock feed – because experts believed its protein could trigger allergies in humans – one particular brand entered the food chain. Food processors received thousands of complaints about reactions, and over 300 items were subject to recall. Advisors to the US EPA called for clinical assessment of exposed individuals to confirm the allergenicity of Bt products – but this has not occurred.
Bacillus thuringiensis itself has a history of safe use, being an approved pesticide for organic producers. However, it is linked to allergic reactions in residents after nearby crops were sprayed, with authorities acknowledging that people with compromised immune systems or existing allergies are particularly susceptible. In 1998, an FDA researcher found that a Bt toxin present in two GM corn varieties shared a sequence of nine to 12 amino acids with the egg yolk allergen vitellogenin, leading to a recommendation for further evaluation. Again, this has never been done. Indian medical investigators found in 2005 that hundreds of agricultural and ginning workers developed allergic reactions at all points of exposure to Bt cotton: some needed antihistamines just to be able to work. The question that arises is, how long does the Bt remain in the cotton?
Testing for safety
There appears to be a correlation between food allergies and exposure of those predisposed (not everyone) to allergens they produce when they become sensitised to GM foods, meaning once a predisposed person is sensitised, adverse responses actually escalate. Reactions typically include hives, itchy skin, and gastric upsets. The UN FAO and WHO are interested in testing GM food safety, but while some have been tested, currently there’s no consistent way of scientifically evaluating GM crops. Critically, while there has been plenty of animal testing, what happens in human cells is unknown. There are no tests to prove a GM crop is safe before release, largely because people generally don’t develop a food allergy until they’ve eaten it several times.
Soy and corn are now endemic. Soy beans, oil, milk and protein go into bread, snack foods and meat pies; soy lecithin (additive 322) is added to spreads, cakes and confectionery; and soybean meal is a stockfeed component. Corn can be present as corn oil and high fructose corn syrup, or masquerade as glucose, fructose, maltodextrin and modified starches (additives 1410, 1412). It also goes into stockfeed. Again, the US is a major producer of corn, with 88 percent of production now GM.
Australia’s labelling laws mean we may not always be told when ingredients are GM. Exemptions include: flavours in a concentration of less than 0.1 percent; when there is no more than one percent per ingredient of an approved GM food unintentionally present as an ingredient or processing aid; and meat and dairy products from animals given GM feed. Until things change, here’s what you can do:
* Read labels and avoid ingredients that may be GM, labelled or not.
* Choose non-GM or GMO-free foods, or ideally 100 percent certified organic.
* Buy from local growers and check their products are GM-free.
* If you eat meat, ensure it’s 100 percent grass- or pasture-fed.
* Grow your own vegetables and fruit where possible.
* If you do suffer allergies, keep a food diary to identify culprits – including GM additives.