Scientists shovel dirt in book for parents

Should you wash the pacifier, if it falls on the ground, or should you lick it off and give it back to your child?

Two scientists tackle this – and hundreds of other questions about dirty and clean in the new book, “Dirt is Good: The Advantage of Germs for Your Child’s Developing Immune System.” Hint – They fall on the side of licking and returning the pacifier, with qualifications.

Both Jack Gilbert and Rob Knight are parents. They’ve been sleepless in the nursery, and worried about vaginal versus c-section births. They’ve framed the science as a series of parent questions from pregnancy and childbirth itself all the way up the playground years. Science nitpickers will find plenty of details about what is called the microbiome – the ecology of all the microscopic creatures who share our skin and our guts. (And our hair, and our armpits, and …)

Gilbert is a PhD and professor of surgery and director of the Microbiome Center at the University of Chicago. Knight is a PhD and professor of pediatrics and computer science at the University of California, San Diego. Gilbert and Knight are not medical doctors, and don’t give medical advice. Their co-writer, Sandra Blakeslee, wrote for the New York Times for many years.

These three bring academic heft to their answers, often quoting specific research projects that have established certain science principles. There are more than 180 references in the book’s appendix.

But scattered in the pages, there is room for humor.

“Should I wash dishes in the dishwasher or by hand? What’s best for microbial health?”

“Is it okay for my child to touch poop?”

Before we look at the answers to these questions, let’s just explain that the last few years have seen an explosion of discoveries about the benefit of healthy microbes in the human gut. People who are infected with one microbe, C. difficile, are sometimes cured by a transplant of feces from a healthy person.  Conditions such as depression and autism have been studied by comparing the microbes living in the intestines of patients with and without those issues. But the explosion of research has led to a corresponding explosion of hype.

Parents may feel especially confused. Perhaps you have heard that exposing children to a certain amount of dirt may help protect them from developing allergies. There is truth to that, and this book goes into pages of details.

On the dish question, the scientists explain that the extra-hot drying cycle of some dishwashers is probably too much cleanliness. They recommend hand washing dishes. As they write, “You want your kid to be exposed to more, not fewer, bacteria in daily life.” On the poop question – they are generally saying it is OK but there are important limits.

Should I take my child to a farm? Should we get a dog?

With careful but clever explanations, the scientists say “yes” to both the farm visits and the dog. But they may surprise you with some other answers. They don’t routinely advise eating yogurt, for example, even though it has the reputation of carrying “good” microbes, often called probiotics. Probiotics is the opposite of antibiotics, which kill bacteria. Probiotics often contain what are called “good” bacteria.

But the book explains that there is no evidence that probiotics always make people’s guts healthier. The whole field of what is known as probiotics is filled with claims that promise one outcome, but frequently don’t deliver it.

Should I give my child probiotics if he has diarrhea?

In this example, the scientists say “Yes.”   Studies do show the value of giving an infant with diarrhea a probiotic. The precise answer to the question gives an education in how the relatively young science of microbial health defines “good” bacteria, and how there is evidence for infants that shows certain probiotics help in that situation.  But they also explain exceptions and nuance.

Reading the whole book may leave you with an awestruck appreciation for what is not known. The true dimension or “population” of microbes that constitutes the healthiest possible gut is not established yet for most people. There are layers and layers of complexity surrounding what we eat, because some of what we eat is “food” for the bacteria themselves and other things we eat are broken down into elements that we actually absorb to power our own cells.

In the 14 chapters and hundreds of questions, the authors slowly educate us to a awesome admiration for the colonies that share our body.  Each person is a planet. Each part of the body carries its own colony of microbes, which thrives in a dynamic communal way, competing with each other for certain resources, but also driving off invaders in some cases that might make the person-planet sick.

For a deeper dive into what is called the “hygiene hypothesis” and how exposure to more diversity in childhood may keep children from allergies and asthma, see this New England Journal of Medicine article.

The more we know about the complicated interplay of these creatures, the more questions we may have. It isn’t an easy time to wash the dishes.


Review of book by pediatrician Perri Klass of The New York Times.

Centrifuge – smashing science into theater


What happens when an actor has to keep putting on a skull-cap, in order to look bald, over and over? Audiences howled, as his errant hairs poked out, and he began his lines imitating Jeff Bezos of Amazon fame. The fake-Jeff was just one character in a set of five science plays. Each play only 10 minutes long and all of them part of a festival known as Centrifuge.

In other plays, reluctant astronauts hunted down life on Saturn’s moon, Enceladus. Newlyweds obeyed the beeped warnings of Fitbits on their wrists predicting “argument” approaching, the way the silly robot of “Lost in space” kept saying “Aliens approaching.” A family hid in a bunker from the frightening reality of ordinary crowds of other people.

Besides a hilarious ribbing of both Bezos and space-exploration rival Elon Musk, a different dystopian play focused on overuse of the mood-enhancer ecstasy or  MDMA. Writer Wayt Gibbs holds a model of that molecule above.

Centrifuge is a week-long improvisation between volunteers of two tribes – theater and science. David Mills and his wife, Catherine Kettrick, lead this project. Full disclosure – I was one of the science writers in May 2017.

You can’t predict what will happen as the week unfolds. With close to 30 people involved, who have full-time other jobs, plenty of obstacles show up. Pets get sick, relatives call, jobs demand. Randomness drives the schedule, just as in a lab where randomness divides mice into controls or experimental subjects.

Monday: Five science writers and five playwrights are randomly assigned to each other, leave the room in minutes and spend time talking in dyads about some research the science writer has brought in.

Wednesday: Five playwrights turn in roughly six-page scripts of new plays inspired by that talk. Actors, who wait for their names to be pulled from hats, are assigned to the five plays. They begin reading the scripts out loud with a randomly assigned director. As I watched, four actors began turning names into people – adding back stories and motivation to small gestures.

Just to shorten this a bit, by Friday the five plays, including 5-minute introductions about science by each writer, debut to the public. A lot of logistics – sets, costumes, lighting, sound and pacing get expertly handled by the theater tribe.

My playwright was Jim Jewell, whose full-time day job is teaching college students composition. The play he created in 48 hours was amazingly complex with four characters from a family. It was less about the gut microbiome research I described to him Monday, and more deeply about how people resist ideas. How might people react to knowing their bodies are more microbial colonizers than “self?” See my earlier post for more about microbiome.

Unlike science, no measurements are taken after this week of mixing. We didn’t examine the audience to rate their hilarity. We didn’t measure the science writers or playwrights to give them a 2 or an 8 in “inspiration.”  But what might have changed in us?

I’m hoping Wayt, as well as Alan Boyle, Greg Scheiderer, and Elle O’Brien will tell me some of their musings on that question for a future post.





Seattle Genetics aims to put drug on front line of cancer

Seattle Genetics hides its big ambitions in a modest-looking set of beige Bothell office-park buildings, while some of its cousins in the local biotech world crowd together in the brainy-hood of Seattle’s South Lake Union. But there is nothing modest about this 18-year-old company, which is plowing forward patiently and aims to make a major splash in the cancer-drug market in 2017.Investors have driven SGEN stock up more than 50 percent this year, largely on the strength of its flagship drug known as Adcetris, which treats Hodgkin lymphoma, a cancer of the lymphatic system that can spread to the lungs, liver or bone marrow. The company employs around 900 full-time staff and will add perhaps 200 next year, said CEO Clay Siegall, who co-founded Seattle Genetics in 1998. For original story