Hygiene Hypothesis

Health secrets of the Amish – NYT

In recent decades, the prevalence of asthma and allergies has increased between two- and threefold in the United States. These days, one in 12 kids has asthma. More are allergic. The uptick is often said to have started in the late 20th century. But the first hint of a population-wide affliction — the sneezing masses — came earlier, in the late 19th century, among the American and British upper classes. Hay fever so
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The Parasite Underground – NYT Mag

When Vik was in his late 20s, blood started appearing in his stool. He found himself rushing to the bathroom as many as nine times a day, and he quit his job at a software company. He received a diagnosis of severe ulcerative colitis, an inflammatory condition of the colon. Steroids, which suppress inflammation, didn’t work for him. Sulfasalazine suppositories offered only the slightest relief. A year and a half afte
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Notes on Parasite Underground

I have a piece in the NYT Mag on the community of people who self-treat with parasites. They operate almost entirely outside of any regulatory or medical oversight. This is a story about desperate people trying to cure themselves with an unproven therapy. It’s not a story about whether the therapy works. We don’t know if it does. And in fact, there’s good evidence, in the form of double-blinded placebo-controlled stu
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Educate your immune system – NYT

IN the last half-century, the prevalence of autoimmune disease — disorders in which the immune system attacks healthy tissue in the body — has increased sharply in the developed world. An estimated one in 13 Americans has one of these often debilitating, generally lifelong conditions. Many, like Type 1 diabetes and celiac disease, are linked with specific gene variants of the immune system, suggesting a strong geneti
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Do you own your microbes?

In the 1990s, scientist Ivan Casas traveled to the Peruvian Andes in search of human microbes. Casas was head of research for a Swedish probiotics company called BioGaia. He believed that mammals, including people, passed beneficial microbes to their young via breast milk. But he’d been unable to isolate one species he thought should be there (Lactobacillus reuteri) in breast milk from women in the US or urban areas
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Mutations in BRCA genes predispose women to cancer, but outside influences shape the ultimate risk

Some of the disparity in the risk from BRCA mutations is generational. One repeated finding is that, by age 50, mutation carriers born in the early twentieth century seem to have a lower risk of cancer than those born later3. The pattern suggests that outside influences interact with genes, and that something in the environment has changed in an unfavourable way. If researchers can figure out what those influences ar
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More on stool banking and self-transplants

I have a piece in the NYT Sunday Review exploring the question: Should we bank our own stool for microbial reconstitution? A few notes and interesting tidbits that didn’t make it into the piece. First, an interesting study linking early-life microbial disturbances with the later development of asthma was just published in Science Translational Medicine. Unlike other studies, which look backward in time to make
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EconTalk podcast

Here’s an hour-long conversation with Russ Roberts over at EconTalk. Very gracious host. I love it that after reading Epidemic, people say, “I bet I had worms.”
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A cure for the Allergy Epidemic?

Allergies are often seen as an accident. Your immune system misinterprets a harmless protein like dust or peanuts as a threat, and when you encounter it, you pay the price with sneezing, wheezing, and in the worst cases, death. What prompts some immune systems to err like this, while others never do? Some of the vulnerability is surely genetic. But comparative studies highlight the importance of environment, beginnin
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