Or, Sometimes Even A Dose Doesn’t Make the Poison
Sometime back a hefty comment thread got going on arsenic levels in white rice; in particular, rice from the southern US where arsenic based pesticides were once used (stuff soaks into the ground, stays there, gets soaked up by rice crops…you get the picture). Accordingly, some people brought up the fact that certain brands of parboiled or converted white rice, e.g., Uncle Ben’s Original, had been shown to have measurable levels of the stuff.
Thread went on, pretty heated at times—someone told someone else to eff off…very unusual for Free the Animal :) —with lots of references links here and there, but what seemed to stop the thread dead in its tracks was this one article: THE ARSENIC EATERS OF STYRIA.
Say the word arsenic and most people think “deadly poison.” Arsenic was the poison of choice for murderers up through the latter part of the nineteenth century, and it is still used for homicides up to the present time. It may, therefore, seem surprising that arsenic was also used extensively as a medicine for centuries, and was even consumed by many people as a health tonic or for cosmetic purposes. A particularly interesting case in point is the arsenic eaters of Styria. […]
These so-called toxicophagi were a group of peasants in Styria and Lower Austria who were in the habit of eating arsenic. They ate the arsenic either to acquire a fresh complexion and appearance of flourishing health or to facilitate respiration when walking or working in the mountainous terrain of the area. These toxicophagi began by taking a small piece of the arsenic, about the size of a lentil (less than half a grain) several times a week. Over time, they gradually increased the dose as the smaller quantity loses its effect. Tschudi gives an example of a man of about sixty years of age who had increased the dose over time to about four grains (enough to kill most people). […]
The debate over the arsenic eaters continued, however, and several individuals attempted to obtain further evidence of the practice. Henry Enfield Roscoe, professor of chemistry at Owens University in Manchester, published a paper on arsenic-eating in 1862. Roscoe communicated with seventeen physicians in Styria, all of whom agreed that it was generally believed that some people there consumed arsenic regularly in substantial quantities without apparent harm. These physicians also provided information on cases of arsenic eating which they had personally observed or which had been related to them by “trustworthy persons.” One physician, for example, described a case of a man who consumed a total of 10 grains (at least twice the normal lethal dose) over two days and still appeared to be in good health. One of Roscoe’s correspondents also provided a sample of a substance consumed by an arsenic eater; chemical analysis had confirmed that this was white arsenic. Roscoe affirmed “That arsenious acid [white arsenic] is taken regularly into the system, by certain persons in Styria, in quantities usually supposed sufficient to produce immediate death.”
The Scottish physician Craig Maclagan also traveled to Styria with a colleague to investigate the subject. He later published his results in the Edinburgh Medical Journal in 1864. While in Styria, Maclagan, along with a Dr. Knappe, watched two arsenic eaters consume what would normally be lethal doses of the chemical. Neither man showed any ill effects from the arsenic on the following day. […]
More recent studies, however, have provided stronger evidence for the development of tolerance to arsenic in certain animals and even in human cells, although the nature and mechanism of such tolerance is not completely understood. Some plants have also been shown to be unusually tolerant to arsenic. In 2001, T. W. Gebel claimed that the development of an elevated tolerance to the acute toxicology of arsenic in humans should be acquirable, and cited some studies supporting the development of arsenic tolerance in humans and other organisms. He went on to caution, however, that the question had to be examined in more detail in order to definitively settle the issue. As chemist William Cullen wrote in his book on arsenic:
“Because the number of arsenic eaters in Styria was relatively small, and because they were very secretive about their habit, it was difficult to unequivocally prove their existence. Nevertheless, there is a considerable body of scientific evidence that Styrian peasants did deliberately ingest poisonous arsenic trioxide.”
The above, excerpted from King of Poisons.
Bottom line, lots of foods have some micrograms of arsenic. Just a quick eyeballing of the Consumer Reports chart at that link, 5 micrograms is a reasonable guess for how much you might get on average per serving. So, putting it in perspective, after 200,000 servings you’ll have ingested a full gram. At 2 servings per day, you’ll have attained a gram by your 274th birthday.
Or, since 4 grains in one ingestion is the average lethal dose (with some of those Styrians demonstrating acquired tolerance to such a dose), you’ll need an accumulated 260,000 micrograms to get there. That’s 52,000 servings. At 2 per day, you’ll get there by your 72nd birthday…so perhaps there is deep cause for concern after all [/sarcasm].
As for me, I have far more important things to worry about. But I do hope you get the lesson and apply it widely. Not to say that some individuals can’t be very sensitive to some “anti-nutrients” or toxins, but there’s otherwise substantial penny wise, pound foolish hand wringing going on. You know what I mean. Don’t sweat the small stuff.