GM industry comment: GM crops have a clear record of safety.  There have been hundreds of animal feeding studies that show that GM crops are safe to eat.

Reply: Most of the papers referred-to like this are usually animal production studies, where diets that were used or outcomes that were measured are not applicable to humans, and hence could not be used to assess effects on human health.  These examples have been found in these sorts of studies:

  • The effects of eating GM silage when humans do not eat silage.  Silage is a type of rotted plant material.
  • Diets were altered using ingredients that are not permissible in human diets eg sand and ground cardboard.
  • Animal production outcomes were measured such as death rates, milk production, feed conversion to various types of carcass weight and even “sticky droppings”.  These are not measures of human health.
  • Animals with completely different physiologies to humans were used as experimental animals.  For example, chickens were often used when they are clearly not comparable to humans – they have feathers, fly, lay eggs, do not suckle their young, have nucleated red blood cells, caeca, air sacks instead of lungs, kidneys that do not produce urine, two “stomachs”, and swallow grit and pebbles to help grind their food – all of which would be considered highly unusual in a human.  Studies on fish are even less comparable.  Cows are also not comparable because, while they are at least mammals compared to many other animal models used in these studies, amongst other things, they have several stomachs, chew their cud, and can digest cellulose so that they can thrive on a diet of grass, which would kill a human.   Pigs are physiologically closer to humans and can be used in feeding studies designed to test human end points but in practice are rarely used due to their size.  That is, they cost more to house and feed than rats.

Other studies cited are often measurements done in vitro or on soil or plants.  Examples of the latter include comparisons of the composition of a GM crop to a non-GM crop and measurements of the amount of transgenic protein expressed in a GM plant.

Furthermore, some of the papers used to support this sort of statement actually show adverse health effects on the animals that have eaten GM crops.

GM industry comment: Americans have eaten billions of meals with GM ingredients over at least a decade and there has never been a documented case of anyone getting ill from eating GM crops.

Reply: Since GM crops were introduced into the US food supply, millions of Americans have gone to hospital and millions of Americans have died.  There has been no investigation into whether any of those hospitalisations or deaths were due, in full or in part, to eating GM crops.  So there is simply no evidence to determine if GM crops have caused any adverse effects in people, or not.