Healthy eating?
Take a considered view of the debate about how what we eat affects our health:
Introduction
Additives
Allergies
Ethics
GM Foods
You can discuss the science of food in our science and technology forum.
Cheaper by the dozen
Tales of the patty
GM Food and Risk of Cancer
Testing for ability to cause tumours is a matter of assessing risks. It is possible to first guess whether there is any chance a chemical might be carcinogenic by looking at its chemical structure. But the risk doesn’t stop there. It is also important to get additional data about the substances the protein may be broken down to in the body (metabolites) which might also be potential carcinogens. Where there is thought to be a possibility of cancer, testing is usually done over a couple of years, feeding the highest possible doses to laboratory rodents.
Did you know ... ?
When used as an organic pest control, US authorities did not require Bt protein to go through carcinogenicity tests
What happens when we eat GM food?
Supposing we eat a chip made from a Bt potato. Below is what basic science would predict. Remember, this GM potato differs from a conventional potato by only one gene, which encodes a protein for insect-resistance.
Mouth: the chip is chewed to break it up mechanically. Enzymic digestion of the carbohydrate begins. Assuming Bt potatoes differ from conventional ones only by a protein, the digestion process here must be identical to that in a conventional potato.
Stomach: acid breaks food down chemically. Enzymic digestion of protein begins. If the human body has enzymes capable of targeting Bt protein, it starts to break down. If not, the protein will pass through to the small intestine, eventually to be eliminated in faeces.
Pancreas: secretes enzymes for the digestion of nucleic acids (DNA and RNA) into the digestive tract. Downstream of here the Bt gene itself, and its associated RNA’s, will start breaking down.
Small intestine: Fat is digested here, and digestion continues for carbohydrates, proteins and nucleic acids. If the body has enzymes capable of targeting Bt protein, it will break right down. If not, the protein will pass through to large intestine elimination in faeces.
Large intestine: material reaching here is of little use to the body - water is absorbed and it is compacted into faeces. Whatever’s left of the Bt proteins and nucleic acids pass through here and out of the body in faeces.
So ... is this what actually happens in the real world? Well, that depends on who you ask...
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