A few people have asked my opinion about this article on wild food by Jo Robinson, including Melissa (below), because my book included a thought experiment on vegetable toxicity. The point of that chapter was to demonstrate that, because we know so little about plant chemicals, it’s easy to construct a narrative that makes veggies look very scary.

May 26, 2013

As always with me, I’m of two minds about this – it’s complicated! This, by the way, is why there’s an asterisk in the title of my book; Basically I think that Robinson is right.*

*Except there’s a lot about this op-ed that’s wrong (and I hope she’s much more careful in the book where there’s more room for nuance).

1. She’s right!

There are thousands of unstudied chemicals in plants that probably contribute to optimum health in small ways, and may, as Robinson claims, stave of chronic diseases. We really don’t understand this stuff. And in the face of uncertainty, diversity is a pretty good defense. Just as a financial planner diversifies investments to minimize risk in an unpredictable world, I think we should be diversifying our diets–eating the rainbow–to deal with the fact that we don’t know which plant chemicals are healthful. Our modern processed-food diet is woefully undiversified (we’ve bet the farm, and our health, on a single approach). Plus, there is some logic to eating a diet that we evolved on. There may be important molecules that used to be ubiquitous that have gotten processed out of our food.

Furthermore, wild foods are often delicious and those chemicals that we don’t get exposed to, have fun surprising flavors if handled correctly. I love the idea of eating diversity.

2. She’s wrong

But, there are a couple things that really bothered me about this op-ed. The first is this:

Studies published within the past 15 years show that much of our produce is relatively low in phytonutrients, which are the compounds with the potential to reduce the risk of four of our modern scourges: cancer, cardiovascular disease, diabetes and dementia.

The key word here is “potential.” The studies show weak association, not a causal connection. People who eat more of the stuff have less risk of cancer, but that may be because those phytochemicals come wrapped up in lots of healthy fiber, or because the type of people who eat lots fruits and vegetables are healthier and richer (they can afford the purple corn and arugula). Be wary of the tendency to reduce the holistic truth that health comes from “eating good food,” down to the reductive idea that health comes from phytochemicals.

Next:

Wild dandelions, once a springtime treat for Native Americans, have seven times more phytonutrients than spinach, which we consider a “superfood.”

Set down your delicious dandelion treat long enough to ask, what the heck is a phytonutrient? The definition: A nourishing chemical made by a plant. I prefer the term “phytochemical” because we shouldn’t assume that these things are nourishing when we know so little about them.

Remember antioxidants? They were all the rage ten years ago, and if the term sounds a little shopworn now it’s probably because people have stopped banging the drum and shouting, “antioxidants will cure everything!” It’s now acknowledged that antioxidants are about as likely to cause, as to cure cancer. (Here’s a nice gloss on this.) One problem is that “antioxidant” is a wastebasket term: tons of different chemicals with radically different effects are tossed into the category. And if “antioxidant” is a wastebasket, “phytonutrient” is a landfill: It’s a giant category that includes antioxidants.

There’s also a passing mention of “cancer-fighting” anthocyanins (chemicals that make plants blue or purple), which is much more specific and a little more interesting. But still, the research on anthocyanins is about at the level of something like the cancer fighting properties of red wine, or chocolate, or coffee. Cool, but hardly conclusive.

Third:

Throughout the ages, our farming ancestors have chosen the least bitter plants to grow in their gardens. It is now known that many of the most beneficial phytonutrients have a bitter, sour or astringent taste.

Why did humans evolve an aversion to bitterness? Because toxic chemicals are bitter. We should give the human palate some credit and acknowledge that some of these “beneficial phytonutrients” will surely turn out to be toxic at high concentrations.

We have two bad assumptions here. First, the assumption that phytonutrients are good. And second, the assumption that there’s never too much of a good thing (that is, if 1 unit of phytochemicals is a superfood, 7 is super duper), and those early farmers were totally misguided to breed plants that were a little less bitter.

There’s an insidious Puritanism in our food logic, implying that the worse something tastes, the better it is for you. I think this is a fundamentally flawed vision. The human body contains embedded wisdom. If we eat mindfully, and really pay attention to what brings us pleasure (true ecstatic pleasure, rather than compulsive craving) I think we will be drawn to the right amount of the various nutrients (known and unknown) that we need.

So I love the idea of eating wild, and incorporating a more colorful diversity of foods into the diet–if the op-ed left it at that I’d be delighted. I just worry that Robinson falls into the old traps of nutritionism by leaning heavily on the scant evidence and trying to pluck putative silver bullets out of the healthy whole.