Perspectives Column
By Greg Ziegler, Professor of Food Science, Penn State University
Food scientists make “fake foods” or “food-like substances” through the process of adulteration. The most important thing about any food is not its nutrient content, but its degree of processing, and “refining” is especially deleterious, or so says Michael Pollan in "In Defense of Food". For Pollan, refined flour is the first industrial fast food.
But the desire for white bread predated the invention of roller mills, as did processes for separating the starchy endosperm from the bran. In a recent paper in the Journal of Food Science, colleagues confirmed consumer preferences for refined over whole wheat bread. We make white bread because that’s what people want.
Pollan erroneously believes that grains are refined to extend their shelf life by making them less nutritious to pests. However, refining was often initially done to remove anti-nutritional factors from plant foods, and to his credit, Pollan provides the example of soy processing to inactivate trypsin inhibitor. Cassava, the third largest source of carbohydrates for human food, is poisonous unless processed properly.
Pollan believes that we have an ancient evolutionary relationship with the seeds of grasses and fruits of plants. Anthropomorphically speaking, “I’ll feed you if you spread around my genes.” With the exception of succulent fruits, the co-evolution of plants and animals has been a struggle, with plants doing their best to evolve ever greater defense mechanisms to deter animals from eating them. Man has an ancient relationship with the plant genus Nicotiana, having been smoking it since 2000 B.C.E. Should we accept then that smoking is healthy?
It’s ironic that the book’s cover illustration is of lettuce, which we eat at a very young stage to avoid an abundance of bitter compounds produced by the plant as it matures. Pollan suggests we eat only those items that would be recognized as food by our great-great grandmother. Many of the plant foods my great-great-grandmother ate were made edible through selective breeding programs to detoxify them. The 14 or so thousand years since the Neolithic revolution is but a blink in evolutionary time. The co-evolution of plants and humans during this period has largely been directed by the later, as was so eloquently explained in Pollan’s Botany of Desire.
The book certainly is a manifesto, and an upper-middle class one at that. Oh that we could all live in Northern California, where fresh fruits and vegetables are available locally and year round. My great-great grandmother, and I suspect Mr. Pollan’s too, survived the winter months mainly on stored root crops, lots of onions. With the invention of canning, generations from my great-grandmother to the present have “put up” more perishable fruits and vegetables to extend their seasons. But despite the provenance and the satisfaction one derives from it, home canning is hardly an option for many.
One non-food, as defined by Pollan, that my great-great grandmother certainly did not eat often or at all is chocolate in its present form. Perhaps I’m partial to this one as chocolate making is among my professional expertise. You see, chocolate is “refined” using steel roller mills, and despite cacao’s ancient origins predating the Maya culture, solid eating chocolate is a “food-like substance” as defined by Pollan.
Pollan impugns scientific research suggesting cacao may have health benefits, referring sarcastically to the Mars Corporation’s endowment of a faculty chair in “chocolate science” at the University of California-Davis, but readily accepts “abundant scientific evidence for the health benefits of alcohol.” My biggest criticism of the book is Pollan’s selective use of science to support his opinions. Though critical of the methodology used in the Nurse’s Health Study and the Women’s Health Initiative, which involved over one hundred thousand women followed for eight years or more, Pollan accepts unquestioningly the science of Kerin O’Dea, who observed ten Australian aborigines for seven weeks. The apparent genius of the study was that when it was over, Dr. O’Dea had no idea what caused the improvements in the group’s health, though Pollan readily accepts the diet-disease link, ignoring the possibility that an increase in physical exercise or even the placebo effect could have explained the short-term results. An alternative hypothesis is that the group’s health improved because they gave up alcohol and ate foods mostly of animal origin, contrary to Pollan’s dietary suggestions, but we will never know since “we can’t extract from such a study precisely which component of the Western diet we need to adjust.”
Along with the Neolithic revolution modern food preservation seems to have become man’s second fall from grace. But with an expanding world population, food science will become increasingly important for better utilization of finite resources. That’s why the World Food Prize selected Dr. Phil Nelson as its 2007 laureate.
The complexity of human-food interactions is undeniable, but the same science that led to the solution for deficiency diseases has also implicated trans fats in present maladies, and can contribute to improved health. Though he plays fast and loose with the science, Pollan’s dietary advice – eat food, not too much, mostly plants – will probably do no harm. Thirty years ago, a food science instructor of mine needed only two words – variety and moderation – but added that two words hardly a book make (and they certainly cannot be sold for $21.95). However, for what it says about the profession, it’s a book every food scientist should read.
