Rohith Kolisetti
Benedict, Eng. 201
April 24, 2012
Bt
or Not Bt:
The
Effects of GM Crops and Agricultural Biotechnology on Human Health
It seems like a major flaw of the human body that if we
go past the daily limit of certain nutrients such as fats, carbs, and sodium, the
body keeps the excess, but does not keep a surplus of vitamins so that you get
super vision from eating a whole bag of carrots or super immunity after
drinking a whole bottle of orange juice. What the hell, body? There has been a
long term love-hate relationship between food and health, but now we introduce
a third party – technology! Innovations in the field of agricultural
biotechnology hope to improve the relation between food and human health. This
can be done in a wide variety of ways including increasing food yield, adding
more nutrients, decreasing the risk of diseases and even preventing bacterial
and viral infections. While all these sound like great prospects in improving
overall human health, an important factor to keep in mind is whether or not
these products will actually be safe for human consumption and the immediate
and long-term effects the use of such technologies could have. After taking a
look at how these products have been put into practice so far, past and current
research and test results, and possible future benefits and risks, consumers
will be able to decide whether or not they want these products to play a role
in their agricultural future.
The modification of
crops to help yield desirable traits is not something new. Steve Hughes and
John Bryant, professors in the School of Biological Sciences at the University
of Exeter in the UK explain that “it is clear from archeological records that
humans have been collecting, saving, and planting seeds for over 12,000 years”
and have been “saving seeds from plants that had desirable characteristics”
(115). This traditional method of plant breeding has evolved with the help of
science and agricultural biotechnology to introduce techniques such as genetic
modification which can produce an even wider variety of crops with desirable
traits. Genetic modification was invented in 1973 and is “based on the natural
gene transfer mechanisms that occur in bacteria” where they can “transfer small
pieces of DNA” between cells (Hughes and Bryant 119). Further advancements
allowed using a distinct set of molecular tools to precisely cut and rejoin DNA
molecules. The application of these living molecular tools to food and agriculture
has resulted in the broad field of agricultural biotechnology, which includes
the technologies used to produce nutraceuticals, derived from nutrition and
pharmaceuticals, and genetically modified food.
“One of the most publicized uses of
biotechnology in agriculture is the modification of corn to express proteins
produced by the common soil bacterium, Bacillus thuringiensis (Bt)” which is “effective
against certain insect pests but are harmless to humans, mammals and birds”
(Falk et al. 1385). Modified crops that have this bacterial gene are
able produce their own Bt toxin to help ward off insects while also maintaining
the health of the farmer by reducing the use of harmful chemical pesticides. An additional benefit provided by crops that are
insect-resistant is the reduction of cancer-causing fungi in those plants. An
article written in The New York Times explains that “contamination by
carcinogenic fungal toxins, for example, is as much as 90 percent lower in
insect-resistant genetically modified corn than in nonmodified corn. This is
because the fungi that make the toxins follow insects boring into the plants.
No insect holes, no fungi, no toxins” (Fedoroff). However a major concern
regarding this technology is the possibility of producing Bt-resistant insects.
If the amount of Bt toxin from the plants is not at a high enough level to kill
the predator insects, the insects may start to develop resistance to the toxin.
This is in fact the case, as field studies have shown the development of
resistance in predator insects about a decade after the Bt spray started being
used (Nottingham 55). The resistance of pests and their link to human health is
shown by the development of antibiotic resistance. During the testing phase of
GM crops, “marker genes are routinely integrated into transgenic crops to
select transformed plants from untransformed plants. A common way of doing this
is by transferring genes that confer antibiotic resistance into plants”
(Nottingham 93). This antibiotic gene sometimes remains in transgenic crops and
if these resistance markers come into contact with pathogens capable of
invading the human body, they could assimilate the antibiotic gene. If this
happened and the pathogen entered a human host, the antibiotic drug therapies
typically used to combat such pathogens would become ineffective. Dr. Stephen
Nottingham, Ph.D., a biologist who specializes in crop protection, has worked
for the USDA, and has been involved in research groups in the UK and projects
in the US aimed at developing novel insect pest control methods clarifies that
“a number of studies have claimed that antibiotic resistance genes present no
risks to humans or animals. However, there is concern that antibiotic
resistance genes will be transferred to bacteria living in the guts of humans
or animals” (Nottingham 93). The possibility of such negative effects create
strong opposition to this technology from anti-GM advocates such as Laura and
Robin Ticciati, authors of Genetically
Modified Foods: Are They Safe? You Decide. who voiced their concerns by explaining
that “unlike chemical or nuclear contamination, new living organisms, bacteria
and viruses will be released into the environment to reproduce, migrate, and
mutate. They will transfer their new characteristics to other organisms”
(Ticciati 5). While it’s true that this is a possibility, “there is something
wrong with the perception of risk” (Ferber) claims microbiologist Abigail
Salyers of the University of Illinois, Urbana-Champaign. She continues by
citing the conclusions made by several panels of antibiotic-resistance experts
where “unanimously, the verdict has been that the chance of
antibiotic-resistance genes getting into intestinal bacteria is minuscule”
(Ferber), and even if they did, “the virtually unanimous verdict is that it
wouldn't matter” (Ferber) due to the fact that these same resistance genes are
already found in a number of bugs. The conclusions of these panels support the
studies Nottingham cited and both agree on the fact that antibiotic-resistance
genes pose limited risk to human health.
While the previous applications of biotechnologies focus on factors
involved in GM crops and their effects on human health, a much more direct
health effect is whether or not there is enough food and if it provides us with
the nutrients we need to survive. This problem was partially addressed thanks
to The Green Revolution, a combination of research, development, and technology
devoted to increasing agriculture production in the U.S. in the mid-1900’s.
Thanks to advancements in science and technology, maximization of yield
potentials was possible and led to an increase in food production. While the
U.S. was lucky to have experienced a green revolution which would help adequately
feed its population, other countries were not so fortunate. Many countries,
especially in Africa, have not had a green revolution and still depend on
traditional farming methods using chemical pesticides, damaging the land and
health of the farmers. The lack of science and technology in their agricultural
development has led to the production of minimal food production which is inadequate
to feed their populations. Scientists at the State University of Iowa, Seed
Science Center explain how “GMs are crops that are genetically formulated with
improved traits or characteristics such as drought resistance, shorter growth
period, improved nutritional content among others and it is one of latest
technological breakthrough in agriculture and food production” (Hassan). They
continue to explain the benefits of GM crops provide by adding “pest
resistance, high yield, tolerance to herbicides such as striga, cold
resistance, high nutritional content and drought tolerance among others”
(Hassan). Despite these benefits, GM crops are met with high resistance
“especially in African countries due to speculations that they are not safe for
human consumption” (Hassan). It’s understandable that the countries are
concerned for the health of their people, but regardless of “speculations on
the safety of GM foods, no one has been able to prove that the technology is
dangerous or harmful to human health. According to the United States Department
of Agriculture, GMs have been tested and proven to have no negative effect on
human health whatsoever and is a technology that can help overcome the
challenge of improving food production both in terms of quality and quantity”
(Hassan). It may be true that just because no one has been able to prove there
are no negative effects doesn’t mean there aren’t any, but is this possibility
of a future problem worse than the very real current problem? While many
African countries continue to refuse GM foods, the government of Kenya is
making a controversial move by allowing the importation of GM food in order to
help fight the hunger and starvation of its people. Even though it is still
illegal to grow GM crops in Kenya, it’s good to see that they realized that not
embracing these new technologies and allowing the “2.5 million people in Kenya
that are in urgent need of food” (Kahare) to die of starvation due to a
speculation wouldn’t have been the best option.
In addition to food quantity being an issue, food quality
must also be taken into consideration. There are two main categories of
nutrition deficiency, undernourishment and malnourishment. Undernourishment
refers to an inadequate caloric intake, when the amount of food eaten is not
enough, while malnourishment refers to a deficiency of one or more essential
nutrients. The UN’s Food and Agriculture Organization (FAO) states that “one in
seven people are chronically malnourished” and “if they manage not to die of
starvation, lack of the necessary levels of proteins, vitamins, minerals and
other micronutrients in their diet” (Bharathan 177). The biotechnological
innovations that stimulated the green revolution helped address the problem of
undernourishment by increasing the quantity of food, saving many people from
starvation. However many of the core crops that were used for this include
crops such as wheat, corn, and rice, where essential nutrients are not present
in adequate amounts. This is where agricultural biotechnology can be of use
once again. Just as science and technology helped improve crop yields and
provide a larger quantity of food, it can also enhance the quality of the food
as well. Gordon Conway, president of the Rockafeller Foundation in New York
explained while addressing a recent OECD conference on GM foods that children
with vitamin A deficiency “are more likely to develop infections and the
severity of the infection is likely to be greater. Each year half a million go
blind and some 2 million die as a result of the deficiency” (Bharathan 177). Paul
F. Lurquin, author of High Tech Harvest:
Understanding Genetically Modified Food Plants supports and adds to
Conway’s claim that “1 to 2 million of these deaths annually could be prevented
if vitamin A were administered to these children” (113). Lurquin, who
recommends the use of a GM food called golden rice which is enhanced with
vitamin A, explains that “a normal daily diet of vitamin-A containing rice
would supply enough of the vitamin to eradicate deficiency and many health
problems in at-risk children” (113). In addition to being able to provide
vitamin A, other varieties of GM crops have been engineered to provide benefits
such as increased vitamin E content by simply overexpressing a gene naturally
found in the same plant and as well as increased iron retention. Lurquin
explains that we need to be careful how much of these enriched substances we
consume because it could become similar to taking medication where food may
come with warning labels such as “Do not exceed the recommended dose” (126) in
order to help consumers avoid potential overdoses. Taking this type of modification
a step further would be to incorporate multiple beneficial nutrients into the
same food, further helping in the fight against malnutrition.
Just as
biotechnology is being used to address the problems of nutritional deficiencies
by enhancing the quality of food through higher nutrient content, it can also
be used to control a variety of age-related diseases. Populations today tend to
have a much longer life expectancy than past generations, but this benefit
comes with problems of its own. Certain neurodegenerative diseases, Alzheimer’s
Disease (AD) for example, has steadily increased over the past decade and is
the “fifth leading cause of death in Americans aged 65 and older” (Scapagnini
27). If this problem is not addressed, the problem will worsen over time and
start to place a serious burden on current and future generations. Scapagnini
explains that “The potential role of curcumin as a preventive agent against brain
aging and neurodegenerative studies identify a novel class of compounds that
could be used for therapeutic purposes as preventive agents against the acute
neurodegenerative conditions that affect many in the world’s increasingly
ageing population” (27). Klaus W.J. Wahle, part of the Cancer Medicine Research
Group in the School of Medicine and Dentistry at Aberdeen University, UK explains
the correlation between the incidence and spreading of cancer cell and the
consumption of certain nutrients called phenolics. He describes the nutrients
beneficial mechanism of action by explaining that “Phenolics can enhance the
body’s immune system to recognize and destroy cancer cells as well as
inhibiting the development of new blood vessels (angiogenesis) that is
necessary for tumour growth. They also attenuate adhesiveness and invasiveness
of cancer cells thereby reducing their metastatic potential” (Wahle 36). This
means that not only do these phenolics have the potential to eliminate existing
cancer cells, but also to stop cancer from developing in the first place. While
some consumers are aware of the benefical aspects of such foods, the naturally
made and presently available sources of the nutrients is not enough to meet the
recommended daily allowance (RDA) and reach its assumed potential. Just as
vitamins were placed in genetically engineered foods to help address the
problem of vitamin deficiencies, if these beneficial compounds were
incorporated into a broader and more available type of food, it would help
decrease the occurrence of these diseases. Autar K. Mattoo, who works in the
Sustainable Agricultural Systems Lab, part of the Agricultural Research Center
of the USDA agrees with this notion and adds that “staple foods such as rice,
corn, wheat and cassava are relatively poor sources of health-promoting
nutrients. In the developing world this contributes to health problems because
the traditional diets are deficient in one or more essential nutrients, causing
malnutrition and disease. Thus, a simple solution entails food biofortification
with externally supplied vitamins and antioxidants, or via genetic manipulation
of nutraceuticals in staple food” (Mattoo 122).
Being able to fix health issues and diseases that are
already present is a very important goal that these new biotechnologies help
meet, but wouldn’t it be even better to prevent these issues from developing in
the first place? While continuing to look for ways to improve human health, the
search for “an easier and affordable means of immunization has led researchers
to the idea of using fruit and vegetable plants as factories for synthesizing
vaccines known as ‘‘edible vaccines’’” (Sharma and Sood 1). In addition to
splicing in genes that produce desired vitamins and other phytonutrients that
can alleviate their respectful deficiencies, bacterial and viral genes are also
being used in foods to grant immunity from disease. Now at first the idea may
seem unappealing, and with good reason, after all who would want to eat
bacteria and viruses? That’s not exactly what happens in this process. When a
person gets a vaccination, what actually happens is that they are being
injected with a weakened or dead version of a pathogen, a virus for example, or
just a weakened part of a pathogen, called an antigen. The purpose of this is
sort of like a practice defense run for your body. Using the weakened pathogen,
your body learns to recognize it and build up defenses quickly in order to
fight it. As you can imagine, your body’s response may not be very fast or
effective at first, which is why you give it a practice run with a vaccine so
that if the actual pathogen happens to invade your body, then you would be able
to respond quickly and effectively and stay healthy. Using vaccines, you can
reduce and even prevent some of the lethal effects virus and bacteria can have
on your body. The problem with using traditional vaccines lie in the costs of
their production and distribution as well as physical limitations such as the
need to be stored in refrigerated conditions as well as having sterile needles
to safely administer the vaccines. This is where innovations in agricultural
biotechnology shine once again, with the introduction of edible plant viruses. Lurquin
explains how part of the pathogen is cloned, and the idea is that “by
expressing partial toxin genes in edible plants, the treated individual’s body
would trigger an immune response to a disabled, safe partial protein toxin”
(127). Sharma and Sood support this claim and explain that these edible vaccines
“do not contain the genes responsible for pathogenesis, making them safe as
they can generate an immune response in the body without causing disease.
Edible vaccines are likely to overcome the hurdles posed by traditional
vaccines, as they can be delivered without needles, do not require
refrigeration and can be made, less expensively, right in the area in which
they will be delivered” (1).
This may
seem alright in theory, but additional safety concerns must be addressed and
tested before this can be approved for human use. Lurquin performed a series of
experiments using this cloned partial toxin gene and introduced it to potatoes.
The potatoes where then fed to mice, and the mice were observed to be producing
antibodies, substances that act as a defense mechanism, to the toxin (Lurquin
127). A viral toxin gene was then introduced to potatoes and tested on human
volunteers. The study, which was done by the Cornell University group in
collaboration with clinicians at the University of Maryland, “successfully
immunized nineteen out of twenty (95 percent) volunteers against the Norwalk
virus, a leading cause of food-borne disease around the world” (Lurquin 128). A
further benefit is that vaccines made by antigens from plants cannot be
contaminated by viruses from animals, including humans, and also viruses that
affect plants do not affect humans (Lurquin 129). Nottingham adds that there
are additional benefits of using plants as a means to deliver vaccines by
including that “large quantities of plant material can be easily produced,
fewer ethical concerns are involved and crops such as modified bananas could
provide an easy source of medicinal drugs, particularly in the developing
world” (77). Nottingham continues by citing a field test with remarkable
results where “bananas have been genetically modified to carry hepatitis B
vaccine, and it was estimated that ten hectares would produce enough to vaccinate
all the children in Mexico” (78). Even though this is very promising
technology, there are still some major issues that need to be worked out before
it can implemented for human use. One simple, yet fairly important fact is that
the crop that is injected with the toxin gene must be consumed raw. That’s
because if you cook or heat to the modified crop, there’s a possibility of
denaturing the biological component (Nottingham 77). This may be why the crops
that are currently in vaccine development include bananas, cowpeas, and other
crops (Nottingham 78) that are more palatable to eat raw, unlike the potatoes
that were used during testing. Many obstacles still lie in the way of edible
vaccines becoming an everyday reality, some of which include “antigen selection,
efficacy in systems, choice of plants, delivery, dosage, safety, public
perception and quality control and licensing” (Sharma and Sood 5).
While still dealing with the human body’s immune system
and the effects GM foods have on it, one must also take into consideration the
possibility of allergic reactions. When an antigen, a substance that causes a
reaction from your immune system is consumed, your body quickly creates a sort
of immune system army to fight off the invader. In an allergic reaction, a
substance similar to an antigen, called an allergen, enters your body but
doesn’t really pose much of a direct threat. In a person with allergies, the
body thinks this allergen is dangerous and thus creates the defenses needed to
fight it, when they are not needed. These defense mechanisms, in addition to
being an overreaction and not needed, also cause damage to the body. The
allergen, which is usually a protein, has been identified in some reactions and
has been removed through genetic engineering. An example where this has been
successful is in Japan, where “a protein that provokes allergic reactions has
been experimentally removed from rice” (Nottingham 92). This allows possibilities such as being able
to enjoy peanuts-based foods, certain cereals, and many other foods without
having to worry about an allergic reaction. However these modifications can
work in an opposite fashion as well. A 1996 study published in The New England
Journal of Medicine by Steve Taylor and his colleagues at the University of
Nebraska, “showed that people allergic to Brazil nuts are also allergic to
soybeans that have been engineered to express a Brazil nut protein to make them
more nourishing” (Ferber). Nottingham adds to this study by explaining that
“most new substances in food due to genetic engineering are likely to be
proteins present in trace amounts. Unfortunately trace amounts of an allergen
are sufficient to trigger physiological reactions” (92). This shows that genetic
modification can not only take out harmful allergens, but displace them into
different foods. The particular brand of soy beans was voluntarily discontinued
before commercialization and the results of this study are reassuring says food
microbiologist Bruce Chassy of the University of Illinois, Urbana-Champaign, a
former food-safety adviser to the U.S. Food and Drug Administration. Chassy
continues to add that “the producers of GM foods screen their products for
allergenicity, he says. Among other methods, they can check to see if the amino
acid sequences of the proteins made by the genes they put into crop plants
resemble those of known food allergens” (Ferber). Nottingham clarifies from
this study that “a genetic modification in one organism can affect a completely
unrelated foodstuff” (93). Nottingham also addresses the increasing rate of allergy-related
asthma and skin conditions and its correlation to the increased use of
chemicals and modification of food, leading him to the conclusion that “as food
becomes more synthesized, through the use of genetic engineering, the problems
of allergic reactions from foods are unlikely to diminish” (Nottingham 93).
Agricultural biotechnology,
including genetic modification and all the other biological modifications that
fall under this category can be implemented in a plethora of ways, which makes
it difficult to give a simple yes or no answer when asking if this technology
is safe for human use or not. Even though GM crops have been in development and
have been used for decades now, there still isn’t any conclusive evidence on
whether these crops are a good or bad thing. That’s because it’s not that
simple. Given all the different changes biotechnology can make along with all
the different varieties of crops it can affect, simply using a blanket
statement such as all GM foods are good or bad is being too critical. Instead,
as new advancements in crop modification arise, they should be viewed in an
individual manner to assess the possible risks and benefits along with any
other concerning factors before they are made commercially available. Because
this is still a relatively new technology, the data for comparison of these
products is limited. We can use the trials done in the past few years along
with current research to help provide us with a better picture of what areas GM
foods clearly provide a benefit and what areas could be improved. Then we will
have a much better understanding of the human health and safety effects the
foods produced using these biotechnologies can have and be able to make better
decisions on whether or not to use these agricultural biotechnologies.
