In my most recent post (see here), I discussed GMOs, or genetically modified organisms, spefically pertaining to food. We discussed how these foods are produced, as well as some history, technology, and business preactices involving GMO.s Today I specifically wanted to discuss the science behind the GMOs, are they safe or not. Is the current body of literature ambuguous in it's findings, and has it been conducted adequately?
I am by no means an expert in the field of GMO research but I have read many articles regarding genetically modified foods on aletrnative health websites, blogs, and even mainstream publication such as the Huffington Post. With that in mind, I have come to be highly suspicious of secondary sources over the years so I try to find the primary documents (in case the original research). Its always a good idea to start research in an area with a few review papers. A 2007 review by By Varzakas (1) noted that while science is obviously a major arena in he tdetermination of a GMO efficacy, other issues such as economical, political, ideologica/philosophical, ethical, and human issues are also concerned. The authors concluded that inadequate legislative measureshave been taken to protect consumers from their consumption. This is based on their reasoning that there has not been enough experimentation conducted to ensure safety. Interestingly these ressearchers are based out of the Institute of Kalmata in Greece. Here in the US, even fewer legislative measures have been taken to ensure the safety of the consumer.
The next review I came across was more favorable towards GMO, but did have obvious flaws in reasoning. A 2008 review by Key et al (2) concluded that "Foods derived from GM crops have been consumed by hundreds of millions of people across the world for more than 15 years, with no reported ill effects (or legal cases related to human health)". These researchers also more or less state that current safety testing in place is adequate, which is contradictory to Varzakas. In my opinion, these conclusion are pretty much laughable (except this is a serious issue!). To begin with, there is no mandated labelling of GMOs in the US so even if there are health ramifications associated with GMOs it will be impossible for future researchers to do an accurate epidemiological study in regards to GMO consumption. In additon the analysyes of such a study would be just about inconceivable, requiring a multivariate regression analyses that, in theory, teased out the numerous other dietary offenses of the average US citizen such as excess sugar consumption and disproportianate w6:w3 ratio. Cause and effect could never be determined.
Secondly, on the conclusion of Key et al, that current testing is adequate, GM foods must go through the FDA for approval, but there is no required independent safety testing, meaning the testing is left to the producer(see fda website). If nothing else, at the minimum, the research is thus subject to an obvious conflict of interest. There has been essentially no long term animal toxicology on any GM product, something the medical community should be concerned about.
As far as some of the actual investigations involving GM foods and health outcomes, researchers such as Arpad Pusztai (3) and Irina Ermakova (4) claim to have found negative outcomes stemming from GMO intake including organ damage and fertility issues whuch I will further discuss shortly. Other researchers have noted negative outcomes as well such as hypertrophy of the villus epithelial cells in the small intestine, hypernucleation, disrupted microvilli, and mitochondrial degeneration, increased numbers of lysosomes and autophagic vacuoles,all indications of an inflammatory reponse. This has been one of the key concerns with GMOs (5). Pusztai suggests transgenic proteins can have major effects on their gastrointestinal tract. As most proteins are immunogenic their consumption may trigger immune/allergic effects both in the mucosal immune system of the gut and more worrisome a systemic effect, where by the reaction affects the whole body. In the latter case, the size, structure, and function of other internal organs would be affected, particularly in individuals more succeptible, such as the immunocompromised (the young and elderly member of a population).
However the work of Pusztai was refuted in the review by Key et al for inadequate sample size and poor methodolgy leading me to question 1) Pusztai's work, but also 2) question why Dr Pusztai has simply not been asked to do further experiments in order to clarify the issues brought into question. To the best of my knowledge,similar studies have not carried out by Pusztai or others. Another important consideration is that Ermakovas work finding infertility following GMO is exclusively sponsored by GreenPeace and is not found in mainstream peer reviewed journals. While I have no qualms with GreenPeace, their ideological believes run contrary to the use of GMO crops and I find it odd that her findings are not published in a respected journal. In addition to Ermakova's work, there is one other 2010 trial that is often discussed in anti-gmo circles.
One of the most unsettling studies in regards to gentically modified foods was first reported in the U.S. by Jefffrey Smith and published in the Huffington Post. (see here). This story has floated around the internet quite a bit. Unfortunately The story is based upon findings that were unpublished in the scientific literature at the time and do this date, the only study I have been able to locate that is even similar to this experiment is an abstract from a Russian journal with no author name listed (6). Supposedly the research was carried out by Russian biologist Alexey V. Surov and colleagfues seeking to find if GM soy beans lead to problems in growth or reproduction. The researchers used hamsters, and divided the population into 4 groups. All groups were fed a normal hamster chow diet (control), in addtion to non-GM soy, GM soy, and "high" amounts of GM soy. They used 5 pairs of hamsters per group. After feeding hamsters for two years over three generations, those on the GM diet, and especially the group on the high GM soy diet, displayed alarming results. By the third generation, most GM soy-fed hamsters lost the ability to have babies. They also suffered slower growth, and a high mortality rate among offspring.
Researchers are said to have selected new pairs from each group of the first generation, which generated a total of 39 litters. There were 52 pups born to the control group (standard chow only) and 78 to the non-GMO soy group. In the GMO feed groups (both groups), only 40 pups were born, and 25% of those born are reported to have died. This equates to a fivefold higher death rate in GMO fed groups than the 5% seen among the controls. Also worthy of note, is that of the hamsters that ate "high" GM soy content, only 1 female hamster gave birth. The researchers claim that she had 16 pups and roughly 20% died. Although no statistics are given, Smith wrote that Surov claimed near total sterility in the third generation of GMO fed hamsters. These finding are certainly unsettling (if they are ever properly substantiated) especially when one considers that endocrine impairment is already being witnessed today. A recent study by Travison found a decline in serum testosterone levels in American men witnessed across all age matched groups compared to just 20 years ago (7).
To wrap things up, I am uneasy about eating GMO food personally, based upon the current body of scientific literature. While it appears that most of the available literature in the peer reviewed journals has not found drastically shocking findings against GMO foods, there are also some findings that are definitely alarming. I do wish that the research that does appear to against GMOs had more mainstream credibilty, however, alot of research has been funded industry (mainly biotech industry but some anti GMO interests) as well. This leaves one to question if market forces are suppressing truth. Big tobacco comes to mind as a reference point.
At the least we can say that there are inadequacies in the research. There are other factors that must be questioned as well; How thorough researchers can be in their work simply due to current knowledge limitations. For example it is only possible to compare currently known properties and constituents of GMO foods in contrast to conventional foods. I would imagine there are still several unknown constiuents that are not even known, making it impossible to analyze these differences. This creates a severe limitation on selection criteria observed. Also results based solely on chemical analysis of macro/micronutrients and known toxins is at best inadequate and, possibly dangerous dangerous. One of the examples I read was compairng the protein, fats, etc of healthy cows to those oo a cow with BSE (mad cow disease). They may be the same, but no one wants to eat the cow with mad cow disease. So with all that said, I would reccomend avoiding GMOs and the best way to do that with out stressing out about it is to once agian just eat real food! Most of these crops are only found in processed foods containing GMO corn, soybean, canola, and the other usual suspects.
-AR
I am by no means an expert in the field of GMO research but I have read many articles regarding genetically modified foods on aletrnative health websites, blogs, and even mainstream publication such as the Huffington Post. With that in mind, I have come to be highly suspicious of secondary sources over the years so I try to find the primary documents (in case the original research). Its always a good idea to start research in an area with a few review papers. A 2007 review by By Varzakas (1) noted that while science is obviously a major arena in he tdetermination of a GMO efficacy, other issues such as economical, political, ideologica/philosophical, ethical, and human issues are also concerned. The authors concluded that inadequate legislative measureshave been taken to protect consumers from their consumption. This is based on their reasoning that there has not been enough experimentation conducted to ensure safety. Interestingly these ressearchers are based out of the Institute of Kalmata in Greece. Here in the US, even fewer legislative measures have been taken to ensure the safety of the consumer.
The next review I came across was more favorable towards GMO, but did have obvious flaws in reasoning. A 2008 review by Key et al (2) concluded that "Foods derived from GM crops have been consumed by hundreds of millions of people across the world for more than 15 years, with no reported ill effects (or legal cases related to human health)". These researchers also more or less state that current safety testing in place is adequate, which is contradictory to Varzakas. In my opinion, these conclusion are pretty much laughable (except this is a serious issue!). To begin with, there is no mandated labelling of GMOs in the US so even if there are health ramifications associated with GMOs it will be impossible for future researchers to do an accurate epidemiological study in regards to GMO consumption. In additon the analysyes of such a study would be just about inconceivable, requiring a multivariate regression analyses that, in theory, teased out the numerous other dietary offenses of the average US citizen such as excess sugar consumption and disproportianate w6:w3 ratio. Cause and effect could never be determined.
Secondly, on the conclusion of Key et al, that current testing is adequate, GM foods must go through the FDA for approval, but there is no required independent safety testing, meaning the testing is left to the producer(see fda website). If nothing else, at the minimum, the research is thus subject to an obvious conflict of interest. There has been essentially no long term animal toxicology on any GM product, something the medical community should be concerned about.
As far as some of the actual investigations involving GM foods and health outcomes, researchers such as Arpad Pusztai (3) and Irina Ermakova (4) claim to have found negative outcomes stemming from GMO intake including organ damage and fertility issues whuch I will further discuss shortly. Other researchers have noted negative outcomes as well such as hypertrophy of the villus epithelial cells in the small intestine, hypernucleation, disrupted microvilli, and mitochondrial degeneration, increased numbers of lysosomes and autophagic vacuoles,all indications of an inflammatory reponse. This has been one of the key concerns with GMOs (5). Pusztai suggests transgenic proteins can have major effects on their gastrointestinal tract. As most proteins are immunogenic their consumption may trigger immune/allergic effects both in the mucosal immune system of the gut and more worrisome a systemic effect, where by the reaction affects the whole body. In the latter case, the size, structure, and function of other internal organs would be affected, particularly in individuals more succeptible, such as the immunocompromised (the young and elderly member of a population).
However the work of Pusztai was refuted in the review by Key et al for inadequate sample size and poor methodolgy leading me to question 1) Pusztai's work, but also 2) question why Dr Pusztai has simply not been asked to do further experiments in order to clarify the issues brought into question. To the best of my knowledge,similar studies have not carried out by Pusztai or others. Another important consideration is that Ermakovas work finding infertility following GMO is exclusively sponsored by GreenPeace and is not found in mainstream peer reviewed journals. While I have no qualms with GreenPeace, their ideological believes run contrary to the use of GMO crops and I find it odd that her findings are not published in a respected journal. In addition to Ermakova's work, there is one other 2010 trial that is often discussed in anti-gmo circles.
One of the most unsettling studies in regards to gentically modified foods was first reported in the U.S. by Jefffrey Smith and published in the Huffington Post. (see here). This story has floated around the internet quite a bit. Unfortunately The story is based upon findings that were unpublished in the scientific literature at the time and do this date, the only study I have been able to locate that is even similar to this experiment is an abstract from a Russian journal with no author name listed (6). Supposedly the research was carried out by Russian biologist Alexey V. Surov and colleagfues seeking to find if GM soy beans lead to problems in growth or reproduction. The researchers used hamsters, and divided the population into 4 groups. All groups were fed a normal hamster chow diet (control), in addtion to non-GM soy, GM soy, and "high" amounts of GM soy. They used 5 pairs of hamsters per group. After feeding hamsters for two years over three generations, those on the GM diet, and especially the group on the high GM soy diet, displayed alarming results. By the third generation, most GM soy-fed hamsters lost the ability to have babies. They also suffered slower growth, and a high mortality rate among offspring.
Researchers are said to have selected new pairs from each group of the first generation, which generated a total of 39 litters. There were 52 pups born to the control group (standard chow only) and 78 to the non-GMO soy group. In the GMO feed groups (both groups), only 40 pups were born, and 25% of those born are reported to have died. This equates to a fivefold higher death rate in GMO fed groups than the 5% seen among the controls. Also worthy of note, is that of the hamsters that ate "high" GM soy content, only 1 female hamster gave birth. The researchers claim that she had 16 pups and roughly 20% died. Although no statistics are given, Smith wrote that Surov claimed near total sterility in the third generation of GMO fed hamsters. These finding are certainly unsettling (if they are ever properly substantiated) especially when one considers that endocrine impairment is already being witnessed today. A recent study by Travison found a decline in serum testosterone levels in American men witnessed across all age matched groups compared to just 20 years ago (7).
To wrap things up, I am uneasy about eating GMO food personally, based upon the current body of scientific literature. While it appears that most of the available literature in the peer reviewed journals has not found drastically shocking findings against GMO foods, there are also some findings that are definitely alarming. I do wish that the research that does appear to against GMOs had more mainstream credibilty, however, alot of research has been funded industry (mainly biotech industry but some anti GMO interests) as well. This leaves one to question if market forces are suppressing truth. Big tobacco comes to mind as a reference point.
At the least we can say that there are inadequacies in the research. There are other factors that must be questioned as well; How thorough researchers can be in their work simply due to current knowledge limitations. For example it is only possible to compare currently known properties and constituents of GMO foods in contrast to conventional foods. I would imagine there are still several unknown constiuents that are not even known, making it impossible to analyze these differences. This creates a severe limitation on selection criteria observed. Also results based solely on chemical analysis of macro/micronutrients and known toxins is at best inadequate and, possibly dangerous dangerous. One of the examples I read was compairng the protein, fats, etc of healthy cows to those oo a cow with BSE (mad cow disease). They may be the same, but no one wants to eat the cow with mad cow disease. So with all that said, I would reccomend avoiding GMOs and the best way to do that with out stressing out about it is to once agian just eat real food! Most of these crops are only found in processed foods containing GMO corn, soybean, canola, and the other usual suspects.
-AR
