What is Genetic
Modification?
Genetic modification
involves the transfer of genes from one species of plant or animal to another,
using techniques that can cause mutations in the genome that may have
unintended consequences for the crop’s safety. (5) The imprecise rearrangement
of genes can create new proteins in these plants that may trigger allergies or
promote disease. (6) Our immune systems often do not recognize these new
proteins and may mount an immune attack against them if they enter our
bloodstream intact. These unintended gene transfers, along with those that are
intended, can lead to significant changes in gut and immune function, and may
have long-term consequences that are not yet known to the scientific and
medical communities.
In genetically modified
corn and cotton, a gene from a bacteria called Bt (Bacillus thuringiensis) is
inserted, which causes a pesticidal toxin to be produced in every cell of the
plant. This Bt-toxin kills insects that eat the plant by breaking down its gut
lining and killing the insect from septicemia caused by the ensuing blood
infection. (7) While this toxin has not been proven to be toxic in this way for
humans and other mammals, several recent studies have suggested this toxin
could have effects on immune health, gut health, liver and kidney function, and
fertility.
The potential dangers
of GMOs
The gut is most
susceptible to the potential dangers of GMO consumption. Bt toxin produced by
GMO corn has been shown to significantly alter immune function in mice, and may
cause disrupted immune function in the gut. (8, 9, 10) One study suggested that
Bt toxin has toxic effects on human cells in vitro, causing them to die
prematurely. (11) This could cause damage to gut endothelial cells if the
toxicity is found to occur in vivo. The potential intestinal effects of GMO
consumption go beyond Bt toxin. Some argue that gut bacteria are capable of
acquiring DNA sequences from GM plants, which could lead to the development of
antibiotic resistance in those microbes. (12) It’s not yet fully understood
what proportion of the GM genes are able to be transferred to gut microbiota.
There have been effects
of GM corn found on organs outside of the intestinal system as well. Analysis
of Monsanto’s own research and independent research by a lab in France
determined that mice and rats eating Bt-toxin producing corn sustained liver
and kidney damage. (13, 14) Other harmful effects were also noticed in the
heart, adrenal glands, spleen and hematopoietic system of these GM corn-fed
rats. Bt toxin has also been demonstrated to reduce fertility in mice, with
fewer offspring being produced than by mice fed on natural crops. (15) While
these are small, preliminary studies, it’s worth investigating the effects GMOs
can have on other organs besides the intestines.
Since the research is
in its infancy, GMOs may have associated health risks that we do not fully
understand. The organization known as The Institute for Responsible Technology
has developed a list of potential hazards of GMO consumption, providing a list
of references for each health risk discussed. They have amassed a great deal of
support for their position that GMOs are dangerous, and much of their
information comes from research studies, clinical experience from doctors, and
anecdotal evidence from farmers and parents of children who thrived on a
GMO-free diet. (Unfortunately, the website’s statements exaggerate the findings
of several studies, so it’s best to be a critical thinker and take the
information with a grain of salt.)
Why is there still
controversy?
Recent reviews have
proposed a different story when it comes to GMO safety, arguing that the bulk
of the evidence demonstrates no health risks associated with GMO consumption.
(16, 17, 18) These reviews found GMOs to be generally safe with no
multigenerational effects, but also recommended that more research continue to
be performed on the health effects of GMO consumption in mammals. It’s
interesting to note, however, that the majority of the studies considered by
these reviews had been conducted by biotechnology companies responsible for
commercializing these GM plants; this conflict of interest could have an effect
on the reporting of certain data. That said, there’s no denying the fact that
independent critical reviews have so far found GMOs to be safe in food.
Unfortunately, credible
research demonstrating the potential dangers of GMOs is not only sparse, it is
also inconsistent. While many scientists argue that GMOs are unsafe for human
consumption, there are many more scientists who suggest that the evidence to
date has not found any significant health risks from ingesting GMOs. It’s
impossible to tell at this point who has the right answer, and it’s unnerving
that there is so much controversy over the safety of a food product that is
present in 60 to 70 percent of processed foods found in grocery stores. (19)
A verdict on GMOs?
There hasn’t been
nearly enough research performed on GMOs to make an informed decision on their
safety. However, lack of proof is not proof against. While the available
evidence is still mixed, it seems likely that genetically modified foods could
have an effect on the immune response as well as the permeability of the gut.
Whether or not this leads to an increase in disease is yet to be determined.
However, if regular consumption of GMOs is able to cause leaky gut, it could
play a role in the recent dramatic rise
in obesity, diabetes, allergies, autoimmune disease, and infertility in our
country.
I’m no conspiracy
theorist, but I think there is enough inconsistency in the available evidence
to support the removal of GMOs from your diet. Fortunately, purchasing
certified non-GMO or organic foods and eating a whole-foods or Paleo diet will
allow you to steer clear of most GMO foods on the market. Until more legitimate
research is conducted, I believe it’s better to be safe than sorry and avoid
genetically modified foods as much as possible.
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