The new proteins that genetic engineering introduces into foods can come from virtually any organism on earth, and most of these new proteins will never have previously been present in significant amounts in human foods. Because people have never before eaten these proteins, the effects that they might have on health will not be known. Thus, the only way to be sure that these foods are safe is to test them thoroughly.

What might be their possible harmful effects? These new proteins could, themselves, cause allergies or be toxic. Alternatively, they could alter the cellular metabolism of the food-producing organism in unintended and unanticipated ways, and in turn, these alterations in metabolism could cause allergens or toxins to be produced in the food.

Another possibility is that, as a result of these alterations in metabolism, the food-producing organism might fail to make some important vitamin or nutrient. Consequently, the genetically engineered food would lack important nutrients that are normally present in the corresponding, natural, non-genetically engineered food.

In summary, the new proteins produced in genetically engineered foods could: a. Themselves, act as allergens or toxins b. Alter the metabolism of the food producing organism, causing it to produce new allergens or toxins, or causing it to be reduced in nutritional value.

All of these possibilities and examples are discussed in greater detail in Section C.

The location at which these mutations occur will be random, because genetic engineers cannot, by and large, control the site at which a recombinant gene is inserted into the DNA of the organism. They can cut and splice genes in the test tube with considerable precision, but the process of inserting those recombinant genes into the host is very imprecise.

These mutagenic events can cause damage in the following ways. First, the recombinant gene may be accidentally inserted into the middle of one of the more-than-one-thousand genes found in most food-producing organisms. This will disrupt that gene, and the organism will no longer be able to produce the protein for which that gene is the blueprint.

That protein might be an enzyme that is important in cellular metabolism. Disrupting the gene for that enzyme could alter cellular metabolism, possibly causing the organism to produce a toxic compound that accumulates in the food produced by the organism. Disrupting metabolism could also prevent the organism from producing certain vitamins or nutrients, and therefore reduce the nutritional value of the food.

Another possibility is that mutations caused by genetic manipulations could alter the expression of the genes of the food-producing organism. This could happen in at least two ways. First, mutationally induced alterations in metabolism, described above, could change the expression of other genes. Second, a genetically engineered gene might be inserted into the DNA very close to an important gene of the food-producing organism, thereby altering the expression of that gene.

These changes in gene expression could cause the food producing organism to produce ten times more or ten times less of an important protein or enzyme. This could cause a variety of problems. First, a protein that is not toxic or allergenic, when present at normal levels, might become toxic or allergenic if present at ten times higher levels. Second, if an important enzyme is produced at a level ten times higher or ten times lower than normal, this could drastically alter cellular metabolism, leading to the production of a toxin or an allergen, or to the inability to produce an important nutrient. Third, if the gene encodes an important regulatory molecule, such as a peptide hormone, producing it at higher or lower levels could disrupt important physiological processes, again leading to changes in food quality or safety.

It must be pointed out that the DNA of most food-producing organisms is very complex. Some of this DNA is in the form of genes, but many parts of the DNA of these organisms do not contain genes. At present the functions of these other portions of the DNA are not understood by science. Genetic engineers usually assume that genetic manipulations will be harmless if are restricted to the DNA of unknown function and avoid genes. However, this argument is really no better than saying that what you do not know cannot hurt you.

The fact that we do not currently understand the function of these DNA sequences does not mean that they do not have important functions. Therefore disrupting these sequences could have unanticipated, long-term or subtle effects that might not be immediately obvious, but that could be damaging to the species or to the quality of the food that it produces. Nature is parsimonious. Therefore, it is likely that these sequences have important functions, even though we do not presently know what they might be. It is unwise to assume that insertions into these sequences will be harmless.

a) Mutations can damage genes naturally present in the DNA of an organism, leading to altered metabolism and to the production of toxins, and to reduced nutritional value of the food.
b) Mutations can alter the expression of normal genes, leading to the production of allergens and toxins, and to reduced nutritional value of the food.
c) Mutations can interfere with other essential, but yet unknown, functions of an organism's DNA.

The molecular mechanisms by which genetic engineering generates mutations and by which these mutations can generate allergens and toxins in food are delineated in more detail in Section C. Concrete examples of such allergens and toxins are presented, as well.

What this means is that, in addition to the changes in biological function intended by the genetic engineer, the introduced DNA may bring about other, unintended changes, some of which may alter the properties of the food produced by the organism in a manner that makes it damaging to health.

Although the potential health hazards of genetically engineered foods are not different from those associated with other foods, namely allergens, toxins, and reduced nutritional value, we show in Section C that the process of genetic engineering, itself is responsible for generating these dangers. That is, the use of the genetic engineering process introduces hazards into the resultant food. Thus, the use of genetic engineering in the development of a new food-producing organism, in itself, constitutes a valid regulatory trigger. Stated in another way, because there is a distinct class of risk that is directly and uniformly associated with the process by which genetically engineered foods are produced, that process-genetic engineering-can be used as a reliable flag for identifying foods that should undergo safety testing.

"Genetically Engineered Food - Safety Problems"
Published by PSRAST