One of the complaints I hear most is “there are no GM food studies done by independents, it’s all company sponsored”. The other one I hear a lot is “there are no long term studies”.
Both of these claims are total BS. Here’s what I found after less than 30 minutes of diligent googling. I have a link to the article (most of them are paywalled), but I have a portion of the abstract also showing.
First, the long-term studies:
We examined 12 long-term studies (of more than 90 days, up to 2 years in duration) and 12 multigenerational studies (from 2 to 5 generations). We referenced the 90-day studies on GM feed for which long-term or multigenerational study data were available. Many parameters have been examined using biochemical analyses, histological examination of specific organs, hematology and the detection of transgenic DNA. The statistical findings and methods have been considered from each study. Results from all the 24 studies do not suggest any health hazards and, in general, there were no statistically significant differences within parameters observed. However, some small differences were observed, though these fell within the normal variation range of the considered parameter and thus had no biological or toxicological significance. If required, a 90-day feeding study performed in rodents, according to the OECD Test Guideline, is generally considered sufficient in order to evaluate the health effects of GM feed. The studies reviewed present evidence to show that GM plants are nutritionally equivalent to their non-GM counterparts and can be safely used in food and feed. (my emphasis)
This is a paywalled article, so I have no idea what studies that they were referring to, but there’s 24 right there. Half of which are multi-generation… not just multi-year. Here are some more…
This was a really neat article. It compared organic soybeans with GM soybeans and a control soybean.
There was an organic soy group (OG), a genetically modified soy group (GG), and a control group (CG). All animals received water and diet ad libitum for 455 days. At the end of this period, the weight of the GG group was the same as that of the OG, and both were higher than CG. Protein intake was similar for the OG and GG, which were significantly lower (p<0.0005) than the CG. The growth rate (GR) of the rats, albumin levels, and total levels of serum protein were comparable for all groups. Hematocrit (p<0.04) and hemoglobin (p<0.03) for the OG and GG were less than the CG. Although the OG and GG demonstrated reduced hematocrit and hemoglobin, both types of soy were utilized in a way similar to casein. This result suggests that the protein quality of soy is parallel to the standard protein casein in terms of growth promotion but not hematological indicators.
In this study, we investigated the duodenum and colon of mice fed on genetically modified (GM) soybean during their whole life span (1–24 months) by focusing our attention on the histological and ultrastructural characteristics of the epithelium, the histochemical pattern of goblet cell mucins, and the growth profile of the coliform population. Our results demonstrate that controls and GM-soybean fed mice are similarly affected by ageing. Moreover, the GM soybean-containing diet does not induce structural alterations in duodenal and colonic epithelium or in coliform population, even after a long term intake. On the other hand, the histochemical approach revealed significant diet-related changes in mucin amounts in the duodenum. In particular, the percentage of villous area occupied by acidic and sulpho-mucin granules decreased from controls to GM-fed animals, whereas neutral mucins did not change.
Therefore, this study was designed to evaluate the effects of transgenic corn on the rats that were fed through three generations with either GM corn or its conventional counterpart. Tissue samples of stomach, duodenum, liver and kidney were obtained for histopathological examinations. The average diameter of glomeruli, thickness of renal cortex and glomerular volume were calculated and number of affected animals/number of examined animals for liver and kidney histopathology were determined. Amounts of urea, urea nitrogen, creatinine, uric acid, total protein, albumin and globulin were determined; enzyme activities of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, gamma glutamyltransferase, creatine kinase and amylase were measured in serum samples. No statistically significant differences were found in relative organ weights of rats within groups but there were some minimal histopathological changes in liver and kidney. Changes in creatinine, total protein and globulin levels were also determined in biochemical analysis.
A seven-month feeding trial with geneticallymodified (GM) Roundup Ready® (RRS®) soybeans was conducted on Atlantic salmon (initial weight 40 g) going through the parr–smolt transformation. The maternal near-isogenic soybean line was used as a non-modified control (non-GM), and the two diets were compositionally similar in all analysed nutrients. The performance and health of the fish were assessed by growth, body composition, organ development, haematological parameters, clinical plasma chemistry and lysozyme levels, with samples collected both in the freshwater- and seawater stages. Intestinal indices exhibited some differences between the groups, with the mid-intestine being consistently smaller in the GM fed fish throughout the experiment, while the distal intestine was different at one sampling point, shortly after seawater transfer. Plasma triacylglycerol (TAG) levels were higher in the GM group overall in the experiment, although the magnitude of the difference was larger around the time of seawater transfer compared to later samplings. Despite differences at individual sampling points, there were no differences in total growth during the trial. All other measured parameters showed no diet related differences. Seawater transfer caused changes in gill Na+K+-ATPase activity and plasma chloride ion concentration, as well as in haematological parameters (red blood cell count, RBC, haematocrit, Hct, haemoglobin, Hb) and plasma glucose concentration. However, both diet groups responded similarly regarding these parameters. Our overall conclusion is that the observed effects of feeding Atlantic salmon with GM soy at a 25% inclusion level were minor, and lack of consistency with previous studies suggests that they might be caused by variations in the soy strains rather than the genetic modification per se.
Long term feeding of Bt-corn – a ten-generation study with quails
A ten-generation experiment with growing and laying quails were carried out to test diets with 40 (starter) or 50% (grower, layer) isogenic or transgenic (Bt 176) corn. Feeding of diets containing genetically-modified corn did not significantly influence health and performance of quails nor did it affect DNA-transfer and quality of meat and eggs of quails compared with the isogenic counterpart.
Ten blasted generations. Wow. I could never do this (I hate birds).
A long-term study over 25 months was conducted to evaluate the effects of genetically modified corn on performance of lactating dairy cows. Thirty-six dairy cows were assigned to two feeding groups and fed with diets based on whole-crop silage, kernels and whole-crop cobs from Bt-corn (Bt-MON810) or its isogenic not genetically modified counterpart (CON) as main components. The study included two consecutive lactations. There were no differences in the chemical composition and estimated net energy content of Bt-MON810 and CON corn components and diets. CON feed samples were negative for the presence of Cry1Ab protein, while in Bt-MON810 feed samples the Cry1Ab protein was detected. Cows fed Bt-MON810 corn had a daily Cry1Ab protein intake of 6.0 mg in the first lactation and 6.1 mg in the second lactation of the trial. Dry matter intake (DMI) was 18.8 and 20.7 kg/cow per day in the first and the second lactation of the trial, with no treatment differences. Similarly, milk yield (23.8 and 29.0 kg/cow per day in the first and the second lactation of the trial) was not affected by dietary treatment. There were no consistent effects of feeding MON810 or its isogenic CON on milk composition or body condition. Thus, the present long-term study demonstrated the compositional and nutritional equivalence of Bt-MON810 and its isogenic CON.
The objective of this study was to investigate the fate of transgenic cry1Ab DNA and the encoded Cry1Ab protein during the metabolic degradation of dietary feed components in dairy cows and a potential transfer to blood, milk, feces or urine. A 25-month long-term feeding trial was conducted on thirty-six Simmentaler cows allocated in two groups fed diets containing either geneticallymodifiedcorn (MON810, N = 18) or the near-isogenic corn variety (N = 18). The nutrients and energy contents of both maize varieties were comparable, ensuring equivalent feed conditions. Due to infertility or other production associated diseases, nine cows per group had to be culled and were replaced by heifers. Feed samples were collected weekly, whereas samples for feces, blood and milk were collected monthly, urine samples were taken bimonthly. All samples were analyzed for cry1Ab DNA by means of end-point PCR (feces, blood, urine) and quantitative real-time PCR (feed, milk). A sensitive and highly specific ELISA, optimized to quantify immunoreactive fragments of the Cry1Ab protein, was used to determine the recombinant protein in the collected samples. Non-transgenic feed samples were free of recombinant DNA and protein within the limit of detection, while in transgenic feed samples both, a 206 bp fragment of cry1Ab and immunoreactive fragments of the Cry1Ab protein were present. In contrast, all blood, milk and urine samples were free of recombinant DNA and protein. The cry1Ab gene was not detected in any fecal sample, whereas immunoreactive fragments of the Cry1Ab protein were detected in feces from all cows fed transgenic feed. Milk of dairy cows fed geneticallymodifiedcorn for 25 months should be classified not different from milk of cows fed non-transgenic corn.
Now, I didn’t include the studies that were about the long-term ecological impacts of GM organisms. Again, there were many that cropped up in my search box, so that’s been done too.
The thing about long term studies is that… well… they take a long time. Then one must spend a lot of time analyzing the results.
There is a long term study going on right now. It has been for the last 20+ years. In America, we have a lot of GM foods. In Europe, there is almost no GM foods. Shockingly, Americans have not been dying of GM food poisoning, increased cancer rates (cancer.org reports that over the last 20 years cancer rates in the US have fallen), or allergy deaths (one product had a major allergen issue and it was pulled very quickly).
Now, as for the other bit, “there are no independent studies”. The website biofortified has provided a list of them, including the funding agency. Now, these papers cover things from spread of GM DNA to how crops affect biodiversity. Here’s the link…
to all 126 of them. They go all the way back to at least 1998. My understanding is that this list is not being actively updated. There is another list called GENERA, with over 400 peer-reviewed research papers that all show the safety and value of GM food. No, I haven’t read them all.
I hope this helps someone.
NOTE: This link goes to my critical review of the Seralini paper (which has been retracted by the publisher).
