From a layperson’s perspective, I found several points in Rosen’s critique small-minded, if not downright misleading. He labels as “inappropriate” studies that show organic vegetables to be high in a precursor to the nutrient quercetin, a powerful antioxidant, because the plants were treated with a natural pesticide that caused them to produce the nutrient. He discounts research showing that organic tomatoes are 79 percent higher than conventional in quercetin because the plants were not grown under conditions typically favored by commercial growers. He complains that a photograph of organic pac choy that had 32 percent more antioxidant phenolics than conventional revealed that flea beetles had feasted on the greens. Finally, he dismisses analysis of 46 trials that showed that organic tomatoes boasted 10 percent more vitamin C than traditional ones, by saying that the difference could be made up with a daily vitamin pill.
When I contacted Benbrook for comment on this review, he was surprisingly upbeat for a man whose work had just been debunked. “What do you expect from the ACSH?” he asked. “I consider it a good sign that this is the first time chemical-agriculture advocates have deemed it necessary to take on one of our reports.”
Benbrook also took on a few of Rosen’s accusations. The few articles he and his team referenced that were not peer-reviewed (4 out of 94) came from presentations delivered at peer-reviewed scientific conferences. Rosen’s assertion that data were selected to prove a point was wrong: Benbrook and his associates applied the same 17 criteria to all studies that they examined to eliminate bias. Any study that failed to meet the criteria—whether it favored organic or conventional—got tossed out, a decision that actually favored conventional growing methods, not the other way around. As a final coup de grace, in order to get to his conclusion that conventional food was more nutritious than organic, Rosen simply ignored any research that showed a difference of less than 10 percent between organic and conventional; for instance, if a set of organic tomatoes were 9 percent higher in vitamin C than their conventional counterparts, he arbitrarily omitted the findings from his calculations as being insignificant. “In some of the studies the differences were significant, in others they were not,” said Benbrook. “We didn’t select. We put them all together. Our conclusion is that if you buy 100 organic items, a few will be 50 percent more nutritious than conventional, some will be more modest, but on average, you get 25 percent more nutrients from organic,” said Benbrook. That doesn’t sound like an admission of failure.
This battle of words is far from over. Benbrook says that in the few months since the report was published, his group has found more studies to include. They plan to come out with an updated report late in the year bolstered by more data. “But you’re not going to see any substantive changes in our findings,” he said.
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