Food Allergies: "What Would Darwin Say?"
A long and fascinating article in the New York Times Magazine this past weekend describes a hopeful new approach for "desensitizing" sufferers of food allergies, a skyrocketing problem of course ("The Allergy Buster"). Along the way, writer Melanie Thernstrom cites a good question posed by a Stanford researcher.
Food allergies are nonsensical. "Why would evolution have us be allergic to the things that sustain us?" [Dr. Kari] Nadeau asks. "What would Darwin say?"There follows a lucid summary of the mechanism that results in an allergic reaction. Then this:
Having a parent or a sibling with allergies (food or environmental) increases the risk that a child will have food allergies. One study of identical twins has led researchers to believe that food allergies are about 70 percent genetic in origin and 30 percent environmental.More:
If allergies are primarily genetic, though, how could their incidence have risen so quickly? The traditional model of genetic change involves natural selection operating through a slow process of mutation, generation by generation, that, furthermore, results in traits that increase survival -- not cause sudden death.
Epidemiologically, food allergies parallel the steep rise of other contemporary epidemics like asthma, diabetes and autoimmune diseases -- a phenomenon for which there has been no convincing explanation. Emerging evidence suggests that food allergies, however, fall in the province of the new field of epigenetics: the science of how the environment can alter the genetic inheritance one generation passes on to the next. One focus of Nadeau's lab [at Stanford University School of Medicine] is studying whether the toxins found in pollution, pesticides or tobacco smoke damage the genes in ways that make children more likely to have allergies and the intimately related disease of asthma.
Nadeau herself is aligned with the school of thought that speculates that the cause of food allergies could be "some element of interaction between genes and the environment -- air pollution, tobacco smoke, chemicals in water or the food you eat. We are ingesting the proteins that are causing the allergies in a very different form and immune environment than when primitive man did."Neo-Darwinism has taken it for granted that genetic mutation sifted by natural selection is all-important in explaining evolutionary developments, for better or worse, and that should presumably include a development such as the precipitous rise of food allergies. The phenomenon is a reminder, then, of the limits of Darwinian explanations. Beyond genetics there is epigenetics.
We've reflected on the implications of this for the intelligent design debate on many occasions.