I recently received an e-mail about beef and pork insulin. The writer inquired:
The writer has some good questions, but sadly, has some misinformation mixed in. First, I must point out that there have been heart medications that worked but have been replaced. Once upon a time, there was a product called "dig leaf" (digitalis is a heart medication that is derived from a plant called foxglove). It worked, but it was totally replaced when newer versions of digitalis became available: first digitoxin, then digoxin.
To get back to insulin: why did pork and beef insulin disappear? Two reasons that I'm aware of: purity, and production cost.
The previous beef and pork insulin products (which were extracted from pancreases from slaughter houses) were impure, and back in the mid-1970's were purified from the level of 90% insulin and 10% "junk" such as C-peptide and other stuff. Later, it was more pure: 95/5, and then 99/1. Semisynthetic human insulin, on the other hand, is very, very, very pure. Why worry about the junk? Because that other stuff that was mixed with the insulin is immunogenic, and can cause allergic reactions -- that we rarely hear of now-a-days from the use of semisynthetic human insulin.
And it's my understanding that the production costs for extracting animal-sourced insulin were rising, as the production costs for making semisynthetic human insulin have fallen, so economically, it's cheaper to make insulin by semisynthetic methods.
What about the claim that some people did well on animal-source insulin and "have had many troubles with the synthetic insulin"? Well, that's been a thought for years, but is readily explained. When folks switched from animal-source, the physicians frequently didn't make the appropriate dose adjustments, and hence many folks receiving semisynthetic human insulin crashed into unexpected hypoglycemia, which left a bad taste in their mouths (to mix a metaphor), especially if their physician had encouraged the switch by suggesting that the new stuff would be the best thing since sliced bread.
And clearly some folks who did well on animal-source insulin and who were switched to semisynthetic human insulin later had problems. That's the nature of diabetes, to do well for years, then slowly develop complications (unless tight glycemic control is maintained). It's easy, but incorrect, to blame the insulin source for the problems.
There is a group of folks based in the UK, who call themselves the Insulin Dependent Diabetes Trust, who have been championing continued availability for animal-source insulin products. I'd suggest the interested reader go to their website, and review their arguments about insulin choices. They also list animal-sourced insulins that are still available.
But will animal-sourced insulin products come back to the United States? No. Like buggy whips, there's just not enough demand for the product. The newer stuff is both better and cheaper. What else could the average patient want?