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Profile: Margie Profet

Evolutionary Theories for Everyday Life by Marguerite Holloway
© Scientific American, April, 1996

On this morning, Seattle's sky and surrounding waters are gray, and even the blue eyes and sweater of Margie Profet seem gray. The evolutionary biologist is explaining that she loves the rain and its flat tones because they make the world look more three-dimensional, and she points to her panoramic view of Portage Bay and the University of Washington to demonstrate: "That glass one over there is my building, the astronomy building."

It is true that a planet that may support life has just been found, but it seems a little premature for an evolutionary biologist to be turning to astronomy. Profet, however, says she is just doing what she has always done: trying to come at a subject that she doesn't know so she can get excited and perhaps find a different perspective "I just wanted a new adventure in life, and I wanted back that math part of my brain that had died."

Profet is also, at least for now, removing herself from a discipline that she helped to popularize and from a storm of criticism over her recent book, Protecting Your Baby-to-Be. Renowned for three evolutionary theories, Profet appears to have crossed a line in the eyes of some of her colleagues in the field of Darwinian medicine, and of many in the medical establishment, when she recommended that pregnant women follow her advice: don't eat pungent vegetables.

In pared-down form, her pregnancy theory posits that the nausea or food aversions many women experience in the first trimester are adaptations designed to protect embryos. Profet argues that some toxins in plants including, for instance, allyl isothiocyanate, a carcinogen found in cabbage, cauliflower and brussels sprouts evolved to ward off herbivores and that some of these compounds could, even in tiny amounts, cause defects during the critical stage when organs are forming. In general, the Pleistocene plants that constituted the diet of our hunter-gatherer ancestors and, hence, those that would have been the force behind the adaptation were even more likely to contain toxins, Profet explains, because agriculturists had not yet selectively bred for crops that were less bitter (that is, less poisonous).

Therefore, her theory contends, we evolved mechanisms to deal with these dietary threats. Hormonal changes make the olfactory systems of pregnant women hypersensitive, able to detect spoilage or teratogens in a single whiff. A woman can thus avoid dangerous foods, relying instead on nutrients that her body stored up before conception. Once the embryonic organs are more or less formed, hormones allow nausea to subside, and women can eat less discriminatingly. Profet correlates the period of pregnancy sickness (from about the third week after conception, when the placenta forms, to 14 weeks after conception ) with the period of organ creation. And although there are no direct studies on the topic, Profet extensively reviews the literature on plant toxins as well as on birth defects.

So, according to Profet, a pregnant woman fleeing the scene of boiling broccoli or brewing coffee is protecting her embryo and should pay attention to her instincts. Which is why Profet says she took her message out of the realm of theoretical biology and academic papers to the realm of the masses and national book tours. But her dietary proscriptions have brought her into often rancorous conflict with obstetricians and nutritionists, as well as with the March of Dimes. Her critics contend that she herself may very well cause birth defects by warning women to stay away from greens.

Others embrace her theory if not her approach. "I was critical of the stance that she has taken. But I was also very supportive of the idea, because I think it is fascinating," says Cassandra E. Henderson of the Montefiore Medical Center, who intends to study plant toxins and to determine whether the compounds cause birth defects in animals. "But I cannot go to the next step and say, 'Don't eat this because it may cause birth defects.' I have no evidence."

For her part, Profet believes there is ample reason for concern. Even if there are no direct data, she says that no one has come up with a criticism that her theory cannot handle. She maintains that her goal was to get women to "err on the side of caution until we have better information" and to stimulate scientific study. "I like looking for solutions to things. And for that you need good theory, and you need good experiments," Profet explains, adding that doing these experiments is not where her talents lie. But she is adamant to the point of self-righteousness about speaking out. "We are talking about life and death. This is not some kind of intellectual fun, you know," Profet states. "People are getting birth defects."

She pauses and rolls her hands up inside her sweater, taking in the room, its wall of windows and wide vista, the binoculars on the table. A view of the water is very important, Profet says, because she did her best thinking in the mid-1980s in San Francisco, in a house with such a view. She had just completed her second bachelor's degree this time in physics at the University of California at Berkeley; she had studied political philosophy at Harvard University for the first one and "I just wanted some time to think about whatever I wanted to think about."

That happened to be evolutionary biology. "I mean, the first month out of physics I went and got a standard biology book. I knew some people in evolutionary biology, and I would have some conversations with them, and I would read everything, and I just started thinking about things. I had this wonderful view and my animals," recalls Profet in her fast and breathless voice, holding out pictures of wild foxes and the raccoon she befriended while living there. "And it was really productive. It was the most productive time of my life, the next three or four years."

Her pregnancy theory, which she first began to research in 1986, was followed in quick succession by two others that are essentially variations on the same theme: ejection. The second one came to her one night when her allergies had suddenly brought on a fit of scratching, and she began to think about people who had fits of coughing and sneezing. "I thought: What do you need these things for? It is almost like you are trying to expel something immediately.

And, well, maybe you are trying to expel it immediately, and if so, what would cause that?" Out of this came her idea that certain forms of allergies evolved as a means of expelling nasty things such as plant toxins and insect venom.

"Every mechanism out there was designed by natural selection to solve a problem, so you have to identify the problem," Profet declares. You have to ask, "During the Pleistocene, would this really have been adaptive?" This reasoning led her next to an explanation of menstruation. She recalls that when she first heard about pregnancy sickness and menstruation as a kid, neither made sense: "I was miffed. No, not miffed. Just puzzled." Then one night in 1988, she dreamed of black triangles embedded in a red background (other aspects of the dream resembled an educational cartoon about menstruation that Profet had seen in high school); her cat woke her up in the middle of the vision, so she was able to remember it. It became clear to Profet that menstruation is more than merely a monthly waste of blood and energy: the process allows the reproductive tract to rid itself of pathogens that attach themselves to sperm.

According to her argument, the myriad bacteria that are found in and around the genitals of men and women hitch rides on sperm, thereby gaining access to the uterus and fallopian tubes. The uterine wall sheds each month so it can cleanse the system, washing away the contaminants that could cause infection or infertility. As with the theory of pregnancy sickness, the menstruation idea awaits further study but Profet specifically urges that gynecologists check women with particularly heavy flows to see if they have active infections. She is again outspoken about being proactive: "You get bad theories that people adhere to, and it is killing people or causing them a lot of harm." In the scientific community, debate continues.

In an upcoming issue of the Quarterly Review of Biology Beverly I. Strassmann of the University of Michigan argues, among other things, that there is no evidence that there are more pathogens in the uterus before menstruation than there are immediately after. Strassmann offers instead another explanation for such bleeding: the uterine lining sloughs off when implantation does not occur, because keeping the womb in a constant state of readiness requires more energy than do the cycles of menstruation and renewal.

Despite her rich intellectual life between 1985 and 1988, when she worked out her theoretical trinity, Profet says her poor economic situation drove her to consider getting a doctorate in anthropology at Harvard she figured that with a stipend and a student's schedule she could do the coursework and keep researching evolutionary biology. "But it was just not like that at all," she says. Graduate school was too stifling for Profet's taste and, she maintains almost wistfully, the wrong place for people who need freedom and who want to use the energy of their twenties and thirties to ask naive questions: "You may be using up a time in life that will just never come again."

She left the program, returning to California and to a part-time job that she had held in the Berkeley laboratory of Bruce Ames, a toxicologist famous for his work on plant toxins and natu- ral carcinogens. (She still maintains an affiliation with the lab.) Over time, her ideas two of them published in the Quarterly Review of Biology and one as a chapter in the 1992 book The Adapted Mind - earned Profet a reputation as a maverick. And in 1993 she won one of the "genius" awards from the MacArthur Foundation.

But Profet seems tired of evolutionary biology for now. "I love the field as I think the field should be," she says in a nearly questioning voice. "But as the field currently is, I don't." Profet says too few of her colleagues make a distinction between a hypothesis and a theory, rushing to publish ideas that are not rigorously worked out but that may have implications for public health. And so she says it suits her just fine to be a visiting scholar in astronomy. "I am here to explore," Profet says. "I think it is good to try to jump into something new every once in a while." As long as her room has a view.

Internet Source: http://darwin.clas.virginia.edu/~rjh9u/profet2.html

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