For years, industrial-food enthusiasts such as Norman Borlaug have attacked organic farming on two grounds: 1) it produces essentially the same nutritional results as chemical-intensive farming, and 2) it’s less productive.

Both of those criticisms are crumbling. This month, the Organic Center released a “state of science” analysis of peer-reviewed studies comparing the nutritional content of organically and conventionally grown veggies. Organic wins by a substantial margin.

Meanwhile, researchers at the University of Wisconsin have published a study (abstract here; press release here) that compared organic and chemical-intensive cropping systems for growing grain and forage (animal feed) crops.

The Organic Center study makes fascinating reading. The authors show that before 2000, very few peer-reviewed studies compared organic and conventional food; the ones that did looked only at “macronutrients” — vitamins and minerals. In that era, there was little consistent evidence pointing to an organic advantage.

Things have changed since. We’re learning that macronutrients only tell part of the story. Evidence is building that micronutrients — antioxidants, phytonutrients, etc. — play a serious role in human nutrition.

Moreover, peer-reviewed studies on the topic have boomed since then. And organic is showing a clear advantage in macronutrients (except vitamin A) and a huge advantage in micronutrients.

Here are some bits I learned from reading through the report.

  • Overall, the nutritional value of conventional veggies has been falling for decades. As farmers (and their input suppliers and extension agents) have worked to maximize yield, food has become significantly less nutritionally dense. In a survey of veggie crops, for example, riboflavin levels dropped nearly 40 percent between 1950 and 1999. (For more info on this, see an earlier Organic Center report called “Still No Free Lunch: Nutrient Levels in the U.S. Food Supply Eroded in Pursuit of Higher Yields.”)
  • Dousing vegetables with water and synthetic nitrogen fertilizer (i.e., conventional ag) triggers biological reactions that actually tend to increase vitamin A production. Score one for Borlaug and the industrial-ag apologists. But it also increases the presence of nitrates — “which is not desirable for overall plant or human health.” And it decreases vitamin C levels as well micronutrient levels. So conventional veggies are often richer than organic in vitamin A and nitrates — and much lower in nearly everything else beneficial.
  • The protein content of conventional U.S-grown corn and soybeans has plunged in recent years — likely due to yield-boosting mania and the near-universal use of genetically modified seeds for those crops.

Overall, this is an extremely interesting study for anyone who wants to understand the effects of chemical-intensive agriculture on nutrition.

As for the study comparing conventional and organic in the field, the press release states the results thusly:

Can organic cropping systems be as productive as conventional systems? The answer is an unqualified “Yes” for alfalfa or wheat and a qualified “Yes, most of the time” for corn and soybeans according to research reported by scientists at the University of Wisconsin-Madison and agricultural consulting firm AGSTAT in the March-April 2008 issue of Agronomy Journal.

In a post last November, I pointed to other peer-reviewed research drawing similar conclusions.