Thursday, December 19, 2019

Iodised Salt and the Problem of Money in Science: A Technological Appendix to Postblogging Technology, September 1949

Where I got this. (Not exactly the source, but fair's fair.)

So I was pretty gobsmacked when I discovered that a lobby of salt manufacturers were holding up salt iodisation in the United States in 1949 (and for a long time after that!) on the grounds that it amounted to "medication by legislation." I got a lot more gobsmacked when I learned just what the scale of the problem was, and one more time when I learned that salt iodisation still isn't mandatory in the United States. I guess I shouldn't have been, given that I grew up during the tobacco industry's rear guard fight, and am facing, like the rest of the world, the consequences of global warming denialism today. 

The actual issues involving the "medicalisation" of iodine have little to do with the tragic death of Little Nell, although iodine tinctures were important to the revolution in public health that prevented many tragic Victorian-era deaths. Here's a link to documents on sickness in the Royal Navy related to "Malta disease," which, in the literature, is actually brucellosis, against which the zealous application of tincture of iodine to all cuts and scrapes is a preventative, but not the cure-all the Granny thought it was.  I could have used actual images of goitre and cretinism as this post's thumbnail, but they're usually horrifying. I guess I'm complicit in sanitising the health risks of iodine deficiency, too. (Attention, salt industry, I want my Bjorn Lomberg money!)

This is a top 1% cretin. Pictures of goitre here

So let's start with where the issues probably begin. If you want to dive into the mind of the turn of the last century, and you are me, and have a compact edition of the Eleventh Edition of the Encyclopedia Britannica lying around the house (less Volume 4), you go to that. And a good thing, too, because I really don't trust myself to summarise this:

"Iodine is obtained either from kelp (the ashes of burnt seaweed) or from the mother-liquors obtained in the purification of Chilean saltpetre. In the former case the seaweed isburnt in large heaps, care being taken thsat too high a temperature is not reached, for if the the ash is allowed to fuse, much iodine is lost by volatilisation. The product obtained after burning is known as either kelp  or varee. Another method of obtaining kelp is by is to heat seaweed in large retorts, whereby tarryand ammoniacal liquors pass over and a very porous residue of kelp remains. A later method consists in boiling the weed with sodium carbonate; the liquid is filtered and hydrochloric acid added to the filtrate; when alginic acid is precipitated, this is also filtered off, the filtrate neutralised by caustic soda, and the whole evaporated to dryness and carbonised; the residue obtained being known as kelp substitute. The kelp obtained by any of these methods is lixiviated with water, which extracts the soluble salts, and the liquid is concentrated, when the less soluble salts, which are chiefly alkaline chlorides, sulphates and carbonates, are crystallised out and are removed. Sulphuric acid is now added to the liquid, and any alkaline sulphides and sulphites present are decomposed, while iodides and bromides are converted into sulphates, and hydriodic and hydrobromic acids are liberated and remain dissolved in the solution. The liquid is run into the iodine still and gently warmed, manganese dioxide in small quantities being added from time to time, when the iodine distills over and is collected." (etc. sv. "Iodine," 14: 724, a-b). 
So, yeah.
Was this really only ten years ago?

Frances P. Bolton
It turns out that while iodine is widely distributed, typically in the range of 3 ppm in soil and 0.05 ppm in seawater, these levels are too low for viable economical extraction. Certain brines (notably including ones associated with the "Chilean saltpetre" deposits of the Atacama Desert) are now used for production of iodine. They are mostly associated with deep drilling for oil and gas. Before the petroleum industry, the Rube Goldbergish process described above for extracting iodine from seaweed really was necessary.  It actually seems unlikely that human beings would need iodine supplementation at all if they were just to eat a meat-rich diet. Iodine is also present in seafood, in sea salts, and in vegetables grown in coastal regions, as well as in modern dairy products due to industrial use of iodine. In short, like most deficiency diseases, goitre and cretinism are diseases of poverty as much as of diet.

As Time tells us, iodine deficiency diseases remained a significant problem at mid-century. I find it hard to believe the problem was as bad in 1949 as it was in WWI, where a third of all draftees seen by one Michigan physician were rejected on the grounds of goiters. Another study, done in the 1920s, found that between 26% and 70% of schoolchildren had goiters in the "goiter belt" stretching from the Great Lakes/Appalachians to the Rocky Mountains. Frances Bolton's push for American iodisation legislation was driven by her concerns about cretinism rather than goitre, and I do not readily find statistics for the prevalence of cretinism in the United States at mid-century, although I do find J. B. Stanbury's 1950 study of a "Family of Goitrous Cretins."

Holy shit. Also, recent studies showing a decade-long rise in average American IQs after the introduction of voluntary iodisation in 1924 would tend to suggest some subclinical level of effect. One can only wonder how much greater the gain would have been had there been a legislative mandate.

So, anyway, how avoidable was this? After an obligatory nod to ancient Chinese wisdom and medieval Arabic scholarship, the traditional account features the discovery of iodine by Bernard Courtois in 1811. An extraordinary contretemps followed, in which Humphrey Davy and party were allowed to pass through the duelling British and French economic blockades to, among other things, consult with Courtois in his laboratory. It wasn't that iodine was already recognised as having special significance apart from being one of the new "elements" being discovered thick and fast. The Emperor had invited him to receive a medal, and it was just gravy that he got to compete with Gay-Lussac for priority in discovering Courtois' discovery.

 Scientists. Anyway, by this time a Geneva physician named Jean-Francois Coindet was already making a name for himself for following up on new, scientific discoveries related to medicine, and he began treating goitre with iodine, both internally and in tinctures, beginning in 1818. Remarkable results were obtained and communicated to the Academie des Science, by this time an "iodine mania" had broken out, and apart from a tendency for iodine treatment to produce paradoxical results in some hyperthyroidal patients, overdosing was rampant. This produced something of a negative response.

If you are wondering how Coindet came to be so fast off the mark, goitre was already suspected to be a deficiency disease by some, although as far as I can tell, assorted miasmal and water-contamination theories mainly held the field. More importantly, marine sponges have been used to treat goitre since antiquity, and was taught in the Materia Medica course at the University of Edinburgh when Coindet was a student there in 1798, getting a good medical education without risking his Reformed ("Calvinist") faith. The discovery that iodine was concentrated in sponge tissue was reported in 1815, and the world was pretty much ripe for the idea that goitre could be treated with chemical iodine by the time that Coindet's trials were reported.

That leaves the connection with cretinism, but this was widely suspected, and I find it in the literature by 1856, because I am lazy and relied on Google Books.  By 1877, iodised salts were available on the British market, and some hospitals were using iodised it. Although, again, because I am lazy, I am relying on a snippet view, and we all know how badly that can go!  The issue, of course, is that unless the price of iodised salt is fixed at the same level as non-iodised, goitre and cretinism will go right on being diseases of poverty.

Or, as we might also say, of capitalism. It is therefore of interest to return to the Eleventh Edition --of 1909!-- to see what it has to say about "Iodine," "Cretinism," and "Goitre." The first notes the use of iodine as an antiseptic, and praises the internal use of iodine for its value in treating syphilis, and notes its use in treating "poisoning by lead and mercury, asthma, aneurysm, arteriosclerosis, angina pectoris, gout, goitre, syphilis, haemophilia, Bright's Disease (nephritis) and bronchitis." Goitre does not go unmentioned, as it could hardly not, but the Britannica might be accused of burying the lede.

This is even more dramatically the case in the article on goitre. (12: 191b-191a). Edmund Owen, former President of the Royal Medical Society of London, Knight of Grace of the Order of St. John of Jerusalem, Chevalier of the Legion of Honour, writes that "[g]oitre is usually ascribed to the use of drinking water impregnated with salts of lime and magnesia" but goes on to conclude that it must be compounded by some "telluric or malarial" influences that co-occur. He is well aware that "removal to the seaside" may help, and that in many cases the "administration of iron and iodine" may be helpful. That out of the way, he gets on lustily to the altogether more interesting subject of surgical interventions. At least chloroform has been invented by now. I've seen similar treatments of the subject from the 1850s that are downright gruesome, as one might imagine in the case of surgical intervention to reduce the size of an organ that may well wrap itself around the trachea and jugular veins as it hypertrophies. The articles on Cretinism, and Metabolic Diseases, to which the former is cross-referenced, are clear that cretinism is a metabolic disease due to deficient thyroidal action. Prophylactic action  by administration of iodine salts might be argued to be beyond the remit of the article, but by this point I can't help having my suspicions, and it is noteworthy that both articles are unsigned.

So what is going on here? It's like Time, of all magazines, says. The average iodine content of table salt is, absent legislation, going down due to modern, low-cost methods of producing it. Presumably, this has been going on for awhile, and that means that the cost of production of the two products has been diverging since salt iodisation was first seriously discussed in the 1850s. Given that it is, and remains, a disease of poverty, why should industry have to give up a share of its profits? It's not fair!

The incidence of goiter in the United States today is 5%.  It would appear to be significantly lower in Canada, although it remains a risk in pregnancy. 

To give this some connection to subjects I talk about more often, fish sauces like the modern Southeast Asian ones and Roman garum, may or may not be rich in iodine, as some fish sauces are made with freshwater fish, and there is considerable loss of iodine due to volatilisation in the secondary boil and in highly evaporated, low quality fish sauces.

No comments:

Post a Comment