Has eliminating hookworms made people fatter?

Okay, yes, obviously when you take the gut parasites out of people, they tend to gain weight immediately after. That’s not exactly what I’m talking about.

First, let’s assume you come from a place where humans and hookworms have co-existed for a long, long time. The hookworms that just about everybody in the American South used to have appear to have come from Africa, so I think it safe to assume that hookworms have probably been infecting a lot of people in Africa for a long time. I don’t know how long–could be anywhere from a few hundred years, if they’d come from somewhere else or recently mutated or something, or could be tens of thousands or hundreds of thousands of years, if they’ve just always been hanging around. Let’s just go with tens of thousands, because if it wasn’t them, it was probably something else.

Over a few thousand years of constant infection, you’d expect to develop some sort of biological response to minimize the chances of death–that is, your ancestors would have evolved over time to be less susceptible to the parasite. Obviously not getting the parasite is one great way to avoid getting killed by it, but let’s assume that’s not an option.

Another solution would be to just absorb food differently–faster, say, or in a manner that circumvents the parts of the gut that are normally infected. Over time, humans and parasites might tend toward an equilibrium–humans stepping up their digestion to make up for what’s lost to the parasite.

Remove the parasite, and equilibrium is lost: suddenly the human starts gaining a lot of weight, especially compared to people from populations that did not adapt to the parasite.

That functional a gut isn’t needed anymore, but it might persist for a while if there are no counter-evolutionary pressures.

Is Acne an Auto-Immune Disorder?

Like our lack of fur, acne remains an evolutionary mystery to me.

Do other furless mammals get acne? Like elephants or whales? Or even chimps; their faces don’t have fur. If so, everyone’s keeping it a secret–I’ve never even seen an add for bonobo anti-acne cream, and with bonobos’ social lives, you know they’d want it.🙂

So far, Google has returned no reports of elephants or whales with acne.

Now, a few skin blemishes here and there are not terribly interesting or mysterious. The weird thing about acne (IMO) is that it pops up at puberty*, and appears to have a genetic component.

Considering that kids with acne tend to feel rather self-conscious about it, I think it reasonable to assume that people with more severe acne have more difficulty with dating than people without. (Remember, some people have acne well into their 30s or beyond.)

Wouldn’t the non-acne people quickly out-compete the acne-people, resulting in less acne among humans? (Okay, now I really want to know if someone has done a study on whether people with more acne have fewer children.) Since acne is extremely common and shows up right as humans reach puberty, this seems like a pretty easy thing to study/find an effect if there is any.

Anyway, I totally remember a reference to acne in Dr. Price’s Nutrition and Physical Degeneration, (one of my favorite books ever,) but can’t find it now. Perhaps I am confusing it with Nutrition and Western Disease or a book with a similar title. At any rate, I recall a picture of a young woman’s back with a caption to the effect that none of the people in this tropical local had acne, which the author could tell rather well since this was one of those tropical locals where people typically walk around with rather little clothing.

The Wikipedia has this to say about the international incidence of acne:

“Rates appear to be lower in rural societies. While some find it affects people of all ethnic groups, it may not occur in the non-Westernized people of Papua New Guinea and Paraguay.

Acne affects 40 to 50 million people in the United States (16%) and approximately 3 to 5 million in Australia (23%). In the United States, acne tends to be more severe in Caucasians than people of African descent.”

I consider these more “hints” than “conclusive proof of anything.”

Back when I was researching hookworms, I ran across these bits:

“The [Hygiene Hypothesis] was first proposed by David P. Strachan who noted that hay fever and eczema were less common in children who belonged to large families. Since then, studies have noted the effect of gastrointestinal worms on the development of allergies in the developing world. For example, a study in Gambia found that eradication of worms in some villages led to increased skin reactions to allergies among children. … [bold mine.]

Moderate hookworm infections have been demonstrated to have beneficial effects on hosts suffering from diseases linked to overactive immune systems. … Research at the University of Nottingham conducted in Ethiopia observed a small subset of people with hookworm infections were half as likely to experience asthma or hay fever. Potential benefits have also been hypothesized in cases of multiple sclerosis, Crohn’s Disease and diabetes.”

So I got to thinking, if allergies and eczema are auto-immune reactions (I know someone in real life, at least, whose skin cracks to the point of bleeding if they eat certain foods, but is otherwise fine if they don’t eat those foods,) why not acne?

Acne is generally considered a minor problem, so people haven’t necessarily spent a ton of time researching it. Googling “acne autoimmune” gets me some Paleo-Dieter folks talking about curing severe cases with a paleo-variant (they’re trying to sell books, so they didn’t let on the details, but I suspect the details have to do with avoiding refined sugar, milk, and wheat.)

While I tend to caution against over-enthusiastic embrace of a diet one’s ancestors most likely haven’t eaten in thousands or ten thousand years, if some folks are reporting a result, then I’d love to see scientists actually test it and try to confirm or disprove it.

The problem with dietary science is that it is incredibly complicated, full of confounds, and most of the experiments you might think up in your head are completely illegal and impractical.

For example, scientists figured out that Pellagra is caused by nutritional deficiency–rather than an infectious agent–by feeding prisoners an all-corn diet until they started showing signs of gross malnutrition. (For the record, the prisoners joined the program voluntarily. “All the corn you can eat” sounded pretty good for the first few months.) Likewise, there was a program during WWII to study the effects of starvation–on voluntary subjects–and try to figure out the best way to save starving people, started because the Allies knew they would have a lot of very real starvation victims on their hands very soon.

These sorts of human experiments are no longer allowed. What a scientist can do to a human being is pretty tightly controlled, because no one wants to accidentally kill their test subjects and universities and the like don’t like getting sued. Even things like the Milgram Experiments would have trouble getting authorized today.

So most of the time with scientific studies, you’re left with using human analogs, which means rats. And rats don’t digest food the exact same way we do–Europeans and Chinese don’t digest food the exact same way, so don’t expect rats to do it the same way, either. An obvious oversight as a result of relying on animal models is that most animals can synthesize Vitamin C, but humans can’t. This made figuring out this whole Vitamin C thing a lot trickier.

Primates are probably a little closer, digestively, to humans, but people get really squeamish about monkey research, and besides, they eat a pretty different diet than we do, too. Gorillas are basically vegan (I bet they eat small bugs by accident all the time, of course,) and chimps have almost no body fat–this is quite remarkable, actually. Gorillas and orangutans have quite a bit of body fat, “normal” levels by human standards. Hunter-gatherers, agriculturalists, and sedentary butt-sitters like us have different amounts, but they still all have some. But chimps and bonobos have vanishingly little; male chimps and bonobos have almost zero body fat, even after being raised in zoos and fed as much food as they want.

Which means that if you’re trying to study diet, chimps and bonobos are probably pretty crappy human analogs.

(And I bet they’re really expensive to keep, relative to mice or having humans fill out surveys and promise to eat more carbs.)

So you’re left with trying to figure out what people are eating and tinker with it in a non-harmful, non-invasive way. You can’t just get a bunch of orphans and raise them from birth on two different diets and see what happens. You get people to fill out questionnaires about what they eat and then see if they happen to drop dead in the next 40 or 50 years.

And that doesn’t even take into account the fact that “corn” can mean a dozen different things to different people. Someone whose ancestors were indigenous to North and South America may digest corn differently than someone from Europe, Africa, or Asia. Different people cook corn differently–we don’t typically use the traditional method of mixing it with lime (the mineral), which frees up certain nutrients and traditionally protected people from Pellagra. We don’t all eat corn in the same combinations with other foods (look at the interaction between the calcium in milk and Vitamin D for one of the ways which combining foods can complicate matters.) And we aren’t necessarily even cooking the same “corn”. Modern hybrid corns may not digest in exactly the same way as corn people were growing a hundred or two hundred years ago. Small differences are sometimes quite important, as we discovered when we realized the artificially-created trans-fats we’d stuck in our foods to replace saturated fats were causing cancer–our bodies were trying to use these fats like normal fats, but when we stuck them into our cell walls, their wonky shapes (on a chemical level, the differences between different kinds of fats can be mostly understood that they are shaped differently, and trans fats have been artificially modified to have a different shape than they would have otherwise,) fucked up the structure of the cells they were in.

In short, this research is really hard, but I still encourage people to go do it and do it well.

 

Anyway, back on topic, here’s another quote from the Wikipedia, on the subject of using parasites to treat autoimmunie disorders:

“While it is recognized that there is probably a genetic disposition in certain individuals for the development of autoimmune diseases, the rate of increase in incidence of autoimmune diseases is not a result of genetic changes in humans; the increased rate of autoimmune-related diseases in the industrialized world is occurring in too short a time to be explained in this way. There is evidence that one of the primary reasons for the increase in autoimmune diseases in industrialized nations is the significant change in environmental factors over the last century. …

Genetic research on the interleukin genes (IL genes) shows that helminths [certain kinds of parasites] have been a major selective force on a subset of these human genes. In other words, helminths have shaped the evolution of at least parts of the human immune system, especially the genes responsible for Crohn’s disease, ulcerative colitis, and celiac disease — and provides further evidence that it is the absence of parasites, and in particular helminths, that has likely caused a substantial portion of the increase in incidence of diseases of immune dysregulation and inflammation in industrialized countries in the last century. …

Studies conducted on mice and rat models of colitis, muscular sclerosis, type 1 diabetes, and asthma have shown helminth-infected subjects to display protection from the disease.”

 

Right, so I’m curious if acne falls into this category, too.

Why an African Parasite got named “American Killer”

The humble-but disgusting hookworm’s scientific name is “Necator americanus”–American Killer. (Actually, there are  several hookworm species, but if you live in the US, this is the one to worry aboutt.)

This parasite, like many others, originated in sub-Saharan Africa, where it still infects about 200 million people. East Asia has another 150 million infected.

Each worm lays lays 9,000 to 10,000 eggs per day in your bowels. You helpfully “deposit” these eggs–prior to indoor plumbing, somewhere on the ground. The eggs hatch, and a week later, the baby worms are ready to burrow their way into the foot of any poor sod unlucky enough to step on them.

The babies go into your bloodstream, burrow into your lungs and throat, and then get coughed and swallowed down into your guts, where they make themselves comfortable, drinking your blood and laying more eggs.

Each individual worm only sucks a drop of blood per day, but no one has just one worm; your intestines soon fill with thousands of the bastards.

One of the interesting side effects of horrible infections and diseases is that, given enough exposure, a population will eventually evolve some sort of immunity. Sickle Cell Anemia, while imperfect, is one such adaptation, rendering some folks in malaria-prone regions less susceptible to the disease. People who do not have these adaptations are easy prey for the disease; so Smallpox, vicious murderer of Europeans, tore through native communities like an atomic bomb, killing some 90% of everyone it got near.

So when some idiot had the bright idea to import slaves from Sub-Saharan Africa, not only did millions of humans suffer and die, but Necator americanus jumped the Atlantic and found a new, less resistant host to infect. Poor southern whites, barefoot and often malnourished (un-nixtamalized corn is a culprit here), became unwitting hosts for an organism against which they had no defenses.

No one knew what was going on. The germ theory of disease hadn’t been developed, and no one was autopsying “white trash” kids when they died.

Historian Thomas D. Clark claims, “By modern American Standards of physical, mental, and moral fitness… more than half of the Johnny Rebs who shelled the woods at Shiloh, Chancellorsville, and Gettysburg, or stood with Pemberton at Vicksburg, might have been kept at home. No one can say how much Pellagra and hookworm helped to sustain the union.” (Quoted in “Parasites: Tales of Humanity’s Most Unwelcome Guests,” by Rosemary Drisdelle.)

A later de-worming campaign in the South (after the parasite was discovered) estimated that 40% of children (of both races, I assume) were infected.

The hookworm turned against the Union, though. As Driselle describes, it passed from infected Southerners to Northerners in the horrifying conditions of the POW camps.

At Andersonville, 13,000 people died of starvation, malnutrition, and disease. Driselle estimates that a third were felled by hookworms, but it is hard to imagine that anyone forced to drink Andersonville’s feces-laden stagnant water would have escaped infection.

It was only in the 1880s and 90s that people started putting together the hookworm infection pieces; in the early 1900s, hookworm eradication campaigns started in the American south. (Tips: Wear shoes; Poop in a toilet.) The parasite that had taken down so many Americans was thus formally dubbed the American Killer, Necator americanus, a great anti-disease naming move if I ever saw one, though not quite as great as the bee parasite, Varroa destructor. I mean, do you want something called V. destructor infecting your bees? Obviously not!

(Seriously, who names a disease AIDS? That makes it sound helpful. Should have named it MURDER disease or something like that.)

Hookworm eradication had notable effects on things like health, school performance, and not dying, which is almost always a good thing. (About that time we also figured out that you can’t live on a 100% corn diet for very long.)

 

From time to time, people ungracefully express their dislike of others in terms fear of disease, describing foreigners as “dirty” or otherwise infectious. While such sentiments are crude and insulting, the fact remains that even the most wonderful of strangers may in fact be carrying diseases to which you have no immunity. And with diseases, like devils, better the disease your ancestors might have survived than one they didn’t.

Terrifying Things

This morning I found a strange, worm-like creature wiggling around in the garden. It was about 5 inches long and thinner than a pin–completely wrong proportions for an earthworm, and further, it was waving its upper end in the air in a manner that earthworms can’t.

I am not worm expert, but my assumption is that there’s only one good reason to be that thin and that long: to make burrowing into someone else’s body easier.

Being a stupid hippie, I wear sandals everywhere (except in snow; I have found it more comfortable to be barefoot in snow than in sandals, and I do not find it comfortable to be barefoot in the snow.)

Forget that shit. I now have nice, sturdy boots for the garden.