A dozen years ago, a New York Times Magazine article titled “Power Steer” changed the way Americans thought about meat. “We are what we eat, it is often said,” wrote author Michael Pollan, “but of course that is only part of the story. We are what what we eat eats too.”
A bit of an awkward phrase, perhaps, but a salient point, not lost on the thousands of Americans who collectively plunk down $380 million a year for grass-fed beef. When we eat animals, we are inheriting their diet—as well as several other aspects of their lives.
But what about when we eat plants? Plants don’t, strictly speaking, eat, but they are no less embedded in their ecological relationships than animals are. Perhaps most importantly, plants take up nutrients from the soil in which they grow, and the meal on offer varies tremendously depending on how that soil is managed. So does it matter, for human nutrition, what our plant-based foods eat?
Healthy soils –> healthy plants –> healthy people?
Recent research from a team of authors led by Newcastle University professor Carlos Leifert suggests it does matter what our plants “eat.” Analyzing 343 studies that compared the nutrient content of organic and conventional food, Leifert and his colleagues found that the organic crops contained an average of 17 percent more antioxidants than the conventional ones and that the effect was particularly pronounced in certain crops, for which organic management offered as much as a 60 percent antioxidant boost. Flavanones, associated with a lower risk of stroke, were an average of 69 percent higher in organic foods tested. Data on pesticide residues varied across the studies, but showed a clear trend: overall levels of pesticides were ten to 100 times lower in organic food.
This study offers some of the best evidence yet that healthy soils lead to healthier plants, and, very likely, healthier people. And here’s the kicker: it’s probably a gross underestimation. Here’s why:
Next generation organics: Beyond the no-no approach
From the plant’s eye view, the certified organic diet is rather like the old-school crash diet you might have tried before prom: it’s all about what you don’t eat. While organic certifiers encourage proactive soil management practices like composting, cover cropping, and soil-building crop rotations, the segment of our organic laws and standards with legal teeth is the list of no-nos: the chemicals that organic producers are not allowed to use. Observing these no-nos is critical for human health—not just to reduce pesticide residue on food, but to reduce chemical exposure for farmworkers and rural communities, and to reduce the carbon footprint of our food system.
And yet, to truly reap the potential of paying attention to what our food plants eat, we need to put them on a more comprehensive diet: the kind that emphasizes eating the good stuff, rather than just avoiding the bad stuff. We don’t have a widely-used system of standards to track which plants are eating good stuff, so this is where knowing your farmer comes in handy.
Meet the Lentil Underground
As part of my dissertation research at UC Berkeley, I got to know a group of farmers in Montana who’ve been assiduously paying attention to their plants’ diets since the late 1980s. At that time, Montana agriculture was dominated by chemically supported wheat monoculture, and the result was soil erosion and rural bankruptcy. So a handful of farmers decided to revamp their farms to provide a better base of soil nutrients. Instead of just planting one crop that was designed to draw nutrients out of the soil, they developed a rotation of crops that would also contribute nutrients back: a community of plants that would feed one another.
Because most of these farmers eat their own crops, they understand on a visceral, anecdotal level that better plant nutrition translates into better human nutrition. I’ve mentioned the Leifert et al. study to a few of them, and they weren’t surprised to learn that organic crops came out 17% ahead of conventional ones in terms of antioxidants. They wondered how much higher that number could be if organic certification standards were explicitly focused on improving plant nutrition, instead of just eliminating the most toxic chemicals. They’d love to partner with researchers to improve the nutritional performance of their systems and pack their lentils and grains full of micronutrients, and they’ve been working with Dr. Alison Harmon, Associate Professor of Food and Nutrition at Montana State University, to educate the public about how to cook and eat lentils.
Of course, this isn’t how American land grant universities have traditionally approached nutrition (of either soil, ecosystems, or humans), so the researchers and the funding needed to do these studies are extremely scarce. But, a growing number of scientists are pushing for change and the USDA is considering taking environmental sustainability into account in our national dietary guidelines–for the first time ever. We may be getting closer to integrating the science of agroecology and the science of nutrition, toward a holistic approach that would follow nutrients from the soil, to plants and animals, to human bodies. As Sir Albert Howard famously wrote in his Agricultural Testament, it’s all one subject.
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