“GMOs” for the Animals: The case of pig-free insulin

by Juan Drewjn, Vegan GMO Latinoamerica.

Diabetes is a disease in which blood sugar (i.e. glucose) is too high. Type 1 diabetes prevents your body from making insulin. With type 2 diabetes -the most common type- your body doesn’t make or use insulin well. Insulin is a protein that is needed to lower glucose levels in blood. The Latest statistics show that incidences of diabetes have risen from 108 million in 1980 to 422 million in 2014. In 2012, an estimated 1.5 million deaths were directly caused by diabetes and another 2.2 million deaths were attributable to high blood glucose.[i] Contrary to a common myth, vegans can have diabetes. (Though it does happen less frequently because a diet high in vegetables is a good way to prevent it.)

Diabetes can cause kidney, nerve, or heart disease, stroke, and even the need to remove a limb. To prevent people from dying the most common modern treatments includes a special diet and the use of insulin. In 1923, Banting and Macleod were awarded the Nobel Prize in physiology or medicine for the discovery of insulin.

The discovery was a massive boon for human diabetes sufferers, but not great news for animals. The only known method to obtain insulin consisted of extracting it directly from the pancreases of pigs and cows. The insulin was then purified, which reduced the chance of the insulin user developing a negative reaction.

On the left, pancreas glands are examined as they arrive from the meatpacking house. On the right, the glands are run through grinders before the next step in the process, insulin extraction. Photo credit: “Stories from the National Museum of American History” 

It took approx. 8,000 pounds of pancreas glands from 23,500 animals to make one pound of insulin.

But in 1978, a new discovery made it possible to take animals out of insulin production. That discovery was thanks to a burgeoning new technology–genetic engineering. Scientists started to synthesize insulin with the use of modified e. coli bacteria. These microscopic organisms became factories of human insulin chains A and B.[i] Compared to porcine and bovine insulin, the insulin from the genetically modified bacteria is cheaper and free from threats of livestock-related shortages. It is also more safe for people who might otherwise have bad reactions to the animal variety, since the new version is an exact copy of genuine human insulin.[ii]. We owe our thanks for this life-saving medicine to genetically modified organisms. And it gets better. Additional improved therapeutic insulin analogues are now possible. According to Vajo and Duckworth (2000), “The availability of molecular genetic techniques opened new windows to create insulin analogs by changing the structure of the native protein and to improve the therapeutic properties.”[iii] In other words, there are now more options for diabetics (like fast acting insulin or one with slowing effect).


Image credit: Wikimedia Commons

Today even more methods of producing insulin with genetically modified non-animal organisms are being tested. One example of this is the GE Safflower made from SemBioSys Genetics Inc. [iv]

Insulin is just the beginning.  Science and technology can help non-human animals at the same time they are helping us. For example, in silico testing methods are computer-modeling techniques that can replace some animals in bio-medical research. And synthetic skin made from stem cells could one day replace animal testing for drug and cosmetics manufacturers.

The insulin example demonstrates that genetic engineering is a valuable tool for creating a world with less human and animal suffering. This important perspective shouldn’t be ignored in conversations about the utility of “GMOs.”



[i] Global report on diabetes – World Health Organization 2016 http://www.who.int/diabetes/global-report/en/

[i] Goeddel, D. V, Kleid, D. G., Bolivar, F., Heyneker, H. L., Yansura, D. G., Crea, R., … Riggs, A. D. (1979). Expression in Escherichia coli of chemically synthesized genes for human insulin. Proceedings of the National Academy of Sciences of the United States of America, 76(1), 106–10. http://doi.org/10.1073/pnas.76.1.106

[ii] Human insuline produces fewer allergic reactions than the animal-derived insulin: Ghazavi, M. K., & Johnston, G. A. (2011). Insulin allergy. Clinics in Dermatology, 29(3), 300–305. http://doi.org/10.1016/j.clindermatol.2010.11.009

[iii] Vajo, Z., & Duckworth, W. C. (2000). Genetically engineered insulin analogs: diabetes in the new millenium. Pharmacological Reviews, 52(1), 1–9. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/10699152

[iv] http://www.plantsciences.ucdavis.edu/Symposium/2007/presentations/Boothe-TSB.pdf

Juan Drewjn is an Argentinian vegan and skeptic. More of his writings on veganism and scientific skepticism can be found at Veganismo Racional. His thoughts on art and science can be found at Barder-Zine. Juan is a proud member of the Alliance for Science at Cornell University and the Vegan GMO leadership team.