Download Health Issues of GM Crops

Health Issues of GM Crops
1. Industrial and pharm plants do produce novel chemicals. These are generally
proteins or short polypeptides. The novel proteins, in turn, produce chemicals
that are usually not proteins.
2. Both proteins and non-proteins can harm humans and animals. Proteins may
act as toxins, hormones or allergens
TOXINS:
e.g. AVIDIN is a potential toxin. It binds biotin, a B vitamin, irreversibly and
makes it ineffective, which can lead to biotin deficiency in living beings.
Bioton deficiency affects skin and hair, central and peripheral nervous
systems and the intestinal tract. Animals ( squirrels, mice, birds, living in an
avidin-corn filed may also be affected, likewise earth worms and soil microorganisms. The company that developed avidin corn is exploring its possible
use as broad spectrum biopesticide.
HORMONS:
Hormones can produce substantial physiological effects in minute doses.
e.g. human growth hormone, that used to treat dwarfism in children has been
produced in transgenetic tobacco. An overdose of growth hormone can
induce giantism in children and acromegaly (overgrowth of bone and
connective tissue associated with reduced life expectancy) in adults.
ALLERGENS:
Adding new proteins to food crops via genetic engineering may suddenly
render familiar food dangerous to sensitive populations. Plant-derived
pharmaceutical and industrial proteins have the potential to cause unintended
immune responses. ( www.ucsusa.org) Allergic reactions to one food can
occur to another if the allergens are unintentionally transferred as a part of
the gene transfer. (www.drs.org.au)
This has occurred already in attempting to transfer the gene for the
expression of METHIONINE, a protein lacking in soybeans but presenting
brazil nuts. It was found that people who have an allergic reaction to brazil
nuts had the same reaction to the engineered soybeans.
e.g. The kiwi fruit was introduced to the US in the 1960s with no known
human allergies. Today people are allergic to this fruit (Pastorello et al 1998,
quoted from: www.agbioworld.org) There is no guarantee that for other
types of foods, GM or no GM, safety of allergic reactions can be insured.
Testing strategies for allergens are still evolving no single test is fully
predictive of human response. ( www.agbioworld.org)
e.g.
Allergenic transfer
Allergic reactions to one food can occur to another if the allergens are unintentionally
transferred as part of the gene transfer. This has occurred already in attempting to transfer the
gene for the expression of methionine, a protein lacking in soybeans, but present in brazil
nuts. It was found that people who have an allergic reaction to brazil nuts had the same
reaction to the engineered soybeans.
Antibiotic resistance
To check which few of the target organism’s cells have incorporated the desired genome
snippet, a ‘marker’ gene is attached to the gene of interest, the marker gene being for
something which is easy to detect. Genes for antibiotic resistance are often used. If an
antibiotic is introduced, the unsuccessful transfers will show up by dying. The risk is that the
antibiotic resistance will be transferred to bacteria living in the mammalian gut, which could
seriously reduce the effectiveness of antibiotic treatments (which are of course already
compromised by overuse of antibiotics in medical treatment and animal feed).
Pesticide residues
The main application of GE food technology so far has been the production of crops (e.g.
soybeans and canola) which can tolerate elevated levels of pesticide - particularly Monsanto’s
Roundup. The logic is that an increased dosage of pesticide early in the cropping cycle will
kill the competing weeds, meaning easier crop management and possibly greater yields. The
downside is the possibility of elevated pesticide residues in the food produced. (On both
yields and pesticide levels there’s evidence both ways, by the way). Certainly Monsanto has
applied for permission to increase permitted levels of residues in soybeans in Australia and
New Zealand, a move strangely at odds with their rhetoric that GE modification of soya and
other crops will substantially decrease pesticide use.
rBST
Since the mid-90s, cows in the USA have been injected with recombinant Bovine
Somatotropin (rBST), which stimulates production of an Insulin-Like Growth Factor (IGF-1),
which in turn increases milk yields (note there’s a glut of milk in the USA anyway).
Unfortunately for the cows, it also produces mastitis (inflammation of the udder), infertility,
lameness, and reduced life expectancy. Unfortunately for humans, IGF-1 can be absorbed,
and has been associated with breast, prostate and colon cancers [16].
Production of novel toxins
In 1989 Showa Denko used GE bacteria to boost yields of L-Tryptophan, food supplement
produced using bacterial fermentation (unfortunately they didn’t label the batches thus
produced). This produced a blood disorder called Eosinophilia Myalgia Syndrome, which
produces a variety of painful symptoms. Officially 37 people died and 1500 left with
permanent disabilities, though there have been estimates of far greater numbers being affected
[17].
Labelling and consumer choice
Australian State Health Ministers will meet in the very near future to decide on the detail of a
system of mandatory labelling. While welcome, this apparently enlightened move should be
read in the context of the post-hoc rationalisation of existing market penetration by the
Australian and New Zealand Food Authority, whereby food not assessed by any Australian
regulatory authority could still be sold, and without labelling [18]. The Federal government is
also pushing hard for a threshold labelling system, which would allow much of the GE
content in food to remain unlabelled.
(www.drs.org.au/new_doctor/73/GM_food_2.html)
3. Toxicologists are currently limited in their ability to assess the risks
presented by complex mixtures, and they have not yet developed methods by
which whole foods (as compared to single chemical compounds) can be fully
evaluated for safety. There can be potential deleterious interactions between
new or enhanced levels of known, toxic agents in BD foods. (
www.agbioworld.org)
4. Whole foods cannot be tested with the high dose strategy currently used for
single chemicals to increase the sensitivity in detecting toxic endpoint (Mc
Kenzie 1999, Royal Society of Canada 2001, quoted from
www.agbioworld.org)