Terra Sigillata

The US FDA has released a statement based on finding from the Texas Department of State Health Services on December 23, 2009:

The Texas Department of State Health Services is warning consumers, especially pregnant or breastfeeding women, to avoid consuming a traditional product called “Nzu” because of the potential health risks from high levels of lead and arsenic.

Nzu, which is consumed as a traditional remedy for morning sickness, has been found by DSHS food inspectors at two African specialty stores – one in the Dallas area and one in Houston. It was also found at a distributor in Houston. The product generally resembles balls of clay or mud and also is called Calabash clay, Calabar stone, Mabele, Argile and La Craie.

Laboratory analysis by DSHS found high levels of lead and arsenic in this product.

Exposure to lead can result in a number of harmful effects, and a developing child is particularly at risk of effects on the brain and nervous system. Arsenic is a carcinogen, and excessive long-term exposure to it has been associated with a range of adverse health effects, including cancers of the urinary bladder, lung and skin.

The Nzu may be covered in a brown or white “dust” and is usually sold in small plastic bags with a handwritten label identifying it as “Nzu” or “Salted Nzu.”

Anyone who has been ingesting the product should contact their health care provider.
The source of the product in Texas is not yet known. Inspectors with DSHS are continuing to investigate.

Ingesting soil, particularly mineral-rich clay, is a practice called geophagy. Various kinds of earth have been a folk remedy common to many cultures, primarily for gastrointestinal complaints.

In fact, that is where the name “Terra Sigillata” is derived.

Terra Sigillata was a fatty clay harvested from the Greek isle of Lemnos and contained at least one component found in today’s Kaopectate diarrhea remedy. A special ceremony would be held to harvest the clay where it would be cut into planchets, embossed with an official seal, then dried and sold. Terra Sigillata stands in pharmacy history as the first trademarked medicine.

Geophagy is also why South Carolinians are sometimes called “sandlappers” and why this Nigerian remedy is often called “Calabash Clay” or “Calabash Chalk.” (Calabash is a coastal town right at the border between North and South Carolina. A style of spiced seafood, usually shrimp, is also known as Calabash.)

But as regards “nzu,” a warning similar to that in Texas came out in 2002 from the Northern Ireland Department of Health, Social Services, and Public Safety (PDF).

In trying to dig up some literature, I believe this may be the first time I have entered a search term in PubMed and come up with zero returns. A search for Calabash chalk comes up with a 2004 paper in Chemosphere for which I cannot obtain full text. The abstract is suggestive that samples were analyzed for several elements and environmental contaminants, with 40 mg/kg of lead being present as well as pesticides. I believe that I will have to consult my geology or Nigerian colleagues for more information on this as I anticipate there is far more literature available but perhaps in regional journals not abstracted by the US National Library of Medicine. I’m primarily curious as to where such samples might be taken from so as to have such high levels of Pb.

In the meantime, I’ll be interested to learn later what case(s) in Texas spurred the current FDA action but I hypothesize that it involved pre-natal, post-natal, or maternal neurological toxicity.

Comments

  1. #1 Shannon
    January 6, 2010

    The sad thing is that there are so few remedies for morning sickness that people turn to folk remedies, possibly poisoning themselves and their fetuses. If there were something safer than Nzu, which worked, you can bet we’d use it. But there isn’t. And that creates the market.

    When I was pregnant, I was sick for nine months, barfing daily and feeling like I was going to barf the rest of the time. Because morning sickness typically isn’t life threatening, and because it involves pregnant women, there’s not much research into how to alleviate it. If your life (and your fetus’s life) isn’t in danger, who cares if you’re miserable?

    So women like me are driven to find alternative remedies – seasickness bands, ginger, small meals, saltines – none of which work.

    “Morning” sickness sure is good birth control though. It’ll be a cold day in hell before I go through that again.

  2. #2 Rose
    January 6, 2010

    And of course, DES was a morning sickness remedy.

    Perhaps that explains why there’s no research into alleviating it. The biggest prior experiment was an epic fail that cost countless lives and limbs and still reverberates today.

  3. #3 Vickiv
    January 6, 2010

    Rose @2: DES and thalidomide.

  4. #4 jane
    January 6, 2010

    Shannon – it’s a pity ginger didn’t work for you, but it works for many people (reports of many women’s experience in practice, plus half a dozen placebo-controlled trials). Some people seem to derive benefit from the seasickness bands as well. No drug or other remedy relieves every single user’s symptoms; it’s too bad you were one of the unlucky people who aren’t helped by anything.

  5. #5 D. C. Sessions
    January 6, 2010

    Because morning sickness typically isn’t life threatening, and because it involves pregnant women, there’s not much research into how to alleviate it. If your life (and your fetus’s life) isn’t in danger, who cares if you’re miserable?

    Misogyny may not be the big reason. Look up Bendectin and you’ll see another explanation for why nobody’s in a big rush to produce morning sickness remedies.

  6. #6 daedalus2u
    January 6, 2010

    It is my understanding that there is a positive association between severity of nausea and positive pregnancy outcomes. It may be that any effective treatment that gets rid of the nausea may increase adverse pregnancy outcomes.

    My hypothesis is that the nausea comes from very high NO levels, and that those levels are necessary in the first trimester when all the proliferation, differentiation and epigenetic programming is going on. NO is an excellent antioxidant, and would protect fetal DNA from problems during replication. High NO also facilitates mitochondria biogenesis in the liver and placenta and raises hemoglobin levels.

    I suspect that arsenic and lead were used because they work. If the high NO hypothesis is correct, then anything that lowers NO levels or that causes oxidative stress would lower nausea levels and would also increase adverse pregnancy outcomes. A higher hemoglobin level might reduce nausea. I would be interested in seeing if there is a correlation between hemoglobin levels and nausea. I would predict an inverse association. A little Epo might raise hemoglobin levels and that increased hemoglobin would lower the NO level, but I don’t think anyone would give a pregnant woman Epo for nausea.

    The problems of placental insufficiency and preeclampsia might result from not enough NO during the first trimester.

  7. #7 phisrow
    January 7, 2010

    This sounds a lot like the “azarcon” and “greta” (both alarmingly leaded folk remedies for gastrointestinal issues.

    Is this sort of thing just bad luck, with so many people putting so many sorts of dirt in their mouths that a few cases are bound to turn out badly, or does lead actually have some efficacy(albeit not worth the nervous system damage) that causes it to be an intended ingredient?

  8. #8 ebrake
    January 7, 2010

    Marijuana/hash cookies/cakes/tea has been a well documented cure for morning sickness for over 6,000 years. Its less toxic than eating raw potatoes and its only side effect is increased appetite and hunger.

    But according to the government its far more dangerous than pharmaceuticals that can deform babies or clay home remedies that have lead and arsenic in them. GO USA USA USA!!!!!

  9. #9 D. C. Sessions
    January 7, 2010

    My hypothesis is that the nausea comes from very high NO levels, and that those levels are necessary in the first trimester when all the proliferation, differentiation and epigenetic programming is going on.

    It is unwise to hypothesize in advance of the data. The roots of morning sickness have been the subject of extensive research, and it’s well to bear in mind that in the absence of some benefit, puking one’s guts out during a time of increased nutrient demand would Not Be Good.

    The keywords are “morning sickness” and “adaptive hypothesis.”

  10. #10 daedalus2u
    January 7, 2010

    DC, I agree, in the absence of some benefit, puking one’s guts out would not be advantageous. There is data that supports the hypothesis. When nausea is taken to the extreme, it causes vomiting usually accompanied by diarrhea. The gut is mostly smooth muscle, which is relaxed by NO. A feature so that when there are gut bacterial infections the NO produced by both the bacteria and iNOS causes gut relaxation which empties it.

    The first trimester is not a time of increased nutrient demand. Metabolic demand actually goes down.

    http://www.ajcn.org/cgi/content/abstract/57/3/353

    The first trimester is the time the fetus is most sensitive to teratogens. There are natural compounds in food that are teratogens, for example mycotoxins. Avoiding those especially in the first trimester would be advantageous. It is not the macronutrients that are teratogens, but the phytotoxins and other xenobiotics that our taste buds and sense of smell have evolved to sense and avoid. Avoiding foods containing compounds that require metabolism by the cytochrome P450 system would make that system easier to control so as to better regulate the things it also does, such as steroid synthesis and significant endocrinology stuff.

    Preeclampsia is associated with reduced nitric oxide levels and increased asymmetric dimethylarginine (an endogenous NOS inhibitor). The vascularization of the uterous and the placenta needs to occur before the increase in fetal metabolic load that occurs in the second trimester. NO is a signaling molecule that is necessary for vascularization. There is a drop in blood pressure in the ~9 to 23 week post conception period. That drop in blood pressure suggests increased NO.

  11. #11 ema
    January 7, 2010

    Some fun facts about NVP:

    –The prevalence of NVP is 70% to 85% (about 50% of women have both nausea and vomiting; 25% have nausea only). About 35% of pregnant women have NVP severe enough to disrupt their daily routine. As many as 50% of these women are not offered treatment for their condition. The most severe form of NVP, hyperemesis gravidarum, is seen in 3 to 20 of every 1,000 pregnancies.

    –The physical discomfort experienced by pregnant women with NVP (even at milder levels of severity) is similar in intensity and character to the nausea and vomiting induced by cancer chemotherapy.

    And speaking of Bendectin (10 mg each of vitamin B6 and doxylamine), the equivalent to use: Vitamin B6 and half a Unisom tablet (not gel cap) every eight hours.

  12. #12 jane
    January 8, 2010

    As far as I know, there was never any evidence that Bendectin actually caused birth defects. It was sued off the market after some users had babies with severe defects, but there was no finding that such defects were more common among Bendectin users than in the general population.