(Roughly) Daily

Allergies seem more prevalent and more severe these days because they are. Theresa MacPhail explains…

… Although allergy researchers may disagree on definitions, symptoms and methodology, all agree on one thing: Allergies have grown worse over the last few decades, and the staggering numbers of allergy sufferers worldwide is likely to continue growing. An estimated 235 million people worldwide have asthma, and anywhere from 240 to 550 million people globally may suffer from food allergies. Drug allergy may affect up to 10% of the world’s population.

There’s a consensus, looking at the last century’s data, that U.S. hay fever rates increased in the mid-20th century. Data suggests that the incidence of asthma increased beginning in the 1960s, peaking sometime in the 1990s. Since then, asthma rates have remained fairly constant. Respiratory allergic diseases and atopic sensitization (or skin allergy) have likely increased over the last few decades. But the most dramatic and visible increase has been the rise in global incidence rates for food allergies, which began in earnest in the 1990s and has grown steadily ever since.

There are, unsurprisingly, multiple theories about the cause. The hygiene hypothesis is one front-runner, positing that people who are “too clean” develop allergies. Many others think it’s our diet, that changes in the way we grow and prepare food have altered our gut microbiome, fueling allergies. Still others argue that manmade chemicals and plastics we encounter daily are making our immune systems more irritable.

What everyone agrees on is that the environment’s influence on our genes, or epigenetics, has played a large role in the rise of allergies, as does the makeup of our nose, gut and skin microbiomes. In the end, it appears, we are at least partially doing this to ourselves. Modern living is likely at the root of the recent rise in allergies…

Our very old immune systems can’t keep up with modern lifestyles and diets, leading to increases in all sorts of chronic health problems like allergies and obesity: “How Modernity Made Us Allergic,” from @TheresaMacphail in @NoemaMag. Eminently worth reading in full.

* Dr. Cathryn R. Nagler

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As we stifle a sneeze, we might send infectious birthday greetings to Alfred Hershey; he was born on this date in 1908. A bacteriologist and geneticist, investigate bacteriophages, or phages—viruses that infect and replicate inside bacteria. In 1952, he and Martha Chase conducted the famous Hershey–Chase, or “Waring Blender” experiment. Their work confirmed that DNA, not protein, was the genetic material of life.

Hershey’s work with bacteriophage earned him a share of the 1969 Nobel Prize in Physiology or Medicine with Max Delbrück and Salvador Luria, “for their discoveries concerning the replication mechanism and the genetic structure of viruses.”

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