What We Know, And Don't Know, About Organic Food


Allison Aubrey, science correspondent, NPR

Many people buy and eat organic food because they believe it's more nutritious. A new study suggests that may not be the case. But with a vast number of influences and variables, from the ripeness of produce to the length of the studies, researchers note that more research is needed.

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A study on the health benefits of organic foods published in the Annals of Internal Medicine spawned a variety of headlines. Organic food isn't more nutritious, but that isn't the point. Organic food might not actually be better for you. Five reasons we should continue to eat organic products. Confused? Well, in a moment, NPR science correspondent Allison Aubrey joins us to run through what we know and what we don't.

If you have questions about organic foods and health, give us a call: 800-989-8255. Email: talk@npr.org. You can also join the conversation on our website. That's at npr.org. Click on TALK OF THE NATION. Allison Aubrey joins us here in Studio 3A.

Thanks very much for coming in.

ALLISON AUBREY, BYLINE: Thanks for having me, Neal.

CONAN: And as I understand it, this study isn't new research as such, but a study based on a lot of other studies.

AUBREY: That's right. Right. And in order to understand sort of what the conclusions are here, you have to understand what researchers set out to do. There are several ways to evaluate potential health benefits. So you can study people who are eating organic food compared to those eating conventionally grown food and look for differences in health. Or you can study the food itself, looking at nutrient levels, vitamins, mineral, mineral content. You can look at pesticide residue, antibiotic-resistant germs or bacteria. And so for the purposes of this new analysis, researchers at Stanford reviewed, as you said, a bunch of studies. They looked at all of these things.

CONAN: And what did they come up with?

AUBREY: Well, what they found was that, indeed, yes, organic food had less pesticide residue. And in some cases, organic meat had less antibiotic-resistant bacteria. But in general - and here's where all of the buzz-generating headlines come from - they found no consistent evidence that organically grown food was more nutritious, meaning it didn't, across the board, have more nutrients or vitamins. And they didn't find any strong evidence that they were measurable health benefits for people eating organic.

But what I should point out here is that the studies of people were very limited. They were short-term and, like, narrowly focused. So they would look at pregnant women, for instance, and say, are pregnant women eating organic, are their children - did their children have left eczema or allergic conditions? So these are sort of narrowly focused studies. They were short-term, and there weren't very many of them.

CONAN: So, in other words they're drawing big conclusions from rather small numbers.

AUBREY: Right. In other words, I think it's really fair to say that this is not the last word on whether organics are healthy or better for you. I think what - the question - here's how I think about it. The question that lots of us want answered - if you buy organic food - is that if I spend the extra money, right, and I buy and eat organic food now, am I somehow going to reduce the risk of developing a disease or cancer 10 or 20 years down the road, right? And unfortunately, this question can't be answered, because the study or studies you need to determine this have never been done.

CONAN: Never been done. And they're going to take time, because these have to be longitudinal studies - in other words, years and years and years.

AUBREY: That's right. Perspective study, studying populations of people, something akin to, you know, the heart studies that have been done, the Framingham study, for instance, that would study people over their lifetime to look at their lifestyle, their diet and to see what influences the risk of heart disease. You need sort of big population studies. And even if these studies were initiated in the future, I have to say, sussing out the particular health benefit of diet can be really tough. So I think, you know, we're just going to have to live with the level of uncertainty, here.

CONAN: Here's an email, and this is Arick(ph), who writes: It's possible some people wrongfully believe organic food is more nutritious. Those of us who eat primarily organic, naturally and locally produced diet don't think there's any more vitamin C in an organic tomato than there is in a conventional tomato. We eat organically because of what isn't in the tomato, namely herbicides, pesticides and chemical fertilizers.

AUBREY: Yeah. Well, you know, here's the thing: organically grown food - the USDA sets standards for that this means. There are technical standards for what organic farmers can and can't use. And typically, it does mean, yes, they're not using synthetic pesticides or synthetic fertilizers. They're composting instead of using synthetic fertilizers. But there are lots of reasons that people buy organic.

As this gentleman says in his email, he doesn't think that his carrot is going to be more nutritious, but people point to environmental stewardship. You know, people point to taste. People point to the I'd-rather-be-safe-than-sorry, the precautionary principle, right? Like if there's any chance that by eating organic now is going to reduce cumulative exposure to pesticides and that sounds beneficial to my health, I'll do it.

CONAN: And they - and as you suggest, they say this is a better way of farming. You're not getting that pesticide or fertilizer running off into the stream and down into the bay.

AUBREY: That's right. If you're using compost instead of fertilizer, there may be less runoff into streams, yeah.

CONAN: There is, however, a significant price difference between organically grown and conventionally grown. And if you can't prove any benefit, why would people want to do it?

AUBREY: Well, I think that this is where we go back to - when you say can't prove benefit, you're talking about this way in which the Stanford researchers set out to prove it in terms of health benefits. But this goes back to what we've just said. There are many reasons why people support organic agriculture. The reason why it's so expensive is because it's more labor intensive to farm organically. And so somebody has got to pay the farmer for the work that he or she is doing.

When you look at the issue of environmental stewardship. I mean, for instance, if you're going to be rotating your crops or making, you know, making your own compost, making compost or using compost instead of commercial fertilizers, these things may take more time. If you're not using the pesticides and fungicides that conventional farmers are using, there may be more labor involved in controlling pests and funguses.

CONAN: Have there been studies - let's turn it on its head, about those who do eat conventional food and do these uses of pesticides and herbicides, do they pile up in the body and create health problems down the road?

AUBREY: Well, that's a really good question. If you think way back to the 1990s, this was a question that came up because we - lawmakers spent a lot of time on the Food Quality Protection Act which was passed on 1996. It seems like a long time ago now. But it was then that a lot of analysis was done looking at - setting reasonable certainty of no-harm standards. Meaning, how much pesticide residue can be on food and not cause any health problems.

And regulators actually put numbers to that and set standards for that. What the researchers found in this study is that when they look to the conventionally grown food, by and large, the conventionally grown food was well within these allowable limits. And so the researchers conclude, hey, if, you know, conventional farming is producing food that have these levels of pesticides that is well within these limits then, you know, probably no harm here.

CONAN: So again, these studies are not cheap. Is there the financial incentive to conduct these enormous, big, long-lasting studies that are going to be - have to be done?

AUBREY: Well, I think it's an interesting question. And I think one of the things we've seen is that this industry is certainly not a niche industry any longer, right?

CONAN: Multibillion dollar business.

AUBREY: We're talking $29 billion in sales, right? And so I think it really depends. The incentives would have to - I think it depends on this: Are consumers buying organic because they believe or need to know that there's a measurable health benefit, or are they buying them for all these other reasons? One we haven't touched on is taste. You know, you might not need to do a study to prove that organic is healthier if somebody already believes it is and says organic - an organic taste better. An organic tomato taste better to them.

CONAN: Is there evidence that one - just to pick a vegetable off the top of my head - carrot is more nutritious than another carrot, whether it's conventionally grown or organically grown?

AUBREY: You know, this is an interesting question and there's a lot of research in this area right now. And what researchers are finding is that, you know, organic isn't the only dividing line here. There are so many things that influence nutrient levels. Everything from the soil to growing conditions, you know, the weather, harvest conditions, the breed of tomato, you know, the type of the tomato or the type of carrots that's grown, right? As our colleague Dan Charles love to say, you can go into a grocery store and look at a tomato, and one have may have three times the level of beta carotene as another, just because it was grown in a different place under different conditions. So there's a lot variability here, and organic isn't the only dividing line.

CONAN: And is there any way to tell?

AUBREY: Well, this is invisible to us, right?


CONAN: So bring your electron microscope.

AUBREY: We cannot tell. So, you know, it's not a surprise if people go for these organic labels. They think that this - but when - in essence the question that lots of people want to know about nutrients, this is really invisible to us.

CONAN: Here's an email from Teresa in Buffalo: As a certified organic grower for the past 17 years, I would like to state, nutrition isn't the issue. No GMOs, no pesticide - GMOs are genetically modified organisms - no pesticides, no herbicides and no quick fertilizers, that is what certified organics is all about. We're certified through NOFA-NY - I'm assuming that's the statewide organization in New York - I have no worries when my child goes into my garden and starts eating vegetables without washing them. And when he was younger, I never had worry about him playing in the dirt and getting the dirt in his mouth while I worked in the garden. So again, there are different reasons for different people.

AUBREY: That's right. Case in point, right there.

CONAN: And as you look at this, nutrition aside, are there certain fruits and vegetables that are just better organic?

AUBREY: Oh, well, this is a very hard question to answer. There's one environmental group - Environmental Working Group is the name of the group. They have analyzed the pesticide residue testing data from the U.S. Department of Agriculture and the FDA. And they came up with ranking for popular fresh produce items. So, you know, at the top of list are apples. Also, strawberries are on the list. These are things that are said to have more pesticide residue.

I think one of the things that tough about this list is that there's a lot of variability, as we have just said. Strawberries from one area or field or farm maybe treated or sprayed more or less. They're just treated differently. And, of course, as we've just mentioned, this is invisible to us as the consumer. We can't see how much pesticide residue is on the food we eat. So I understand people's motivation for being interested in this sort of lists. I think it's kind of tough, though.

CONAN: This is obviously an emotional issue for a lot of people too. They get very upset when - what their beliefs are challenged.

AUBREY: Absolutely. I think that, particularly in this day and age, you know, I mean, organic is part and parcel of a sort of cultural movement, of a food renaissance, right? And so for someone to say that this is not beneficial, it sort of feels like an attack. When in essence, I think all these researchers are saying is like, look, the evidence of health benefits are limited. Let's keep studying this.

CONAN: We're talking with Allison Aubrey, NPR science correspondent, about a study of studies that was recently published in the Annals of Internal Medicine about the benefits, if any, of organically grown food. You're listening to TALK OF THE NATION from NPR News. And let's get a caller on the line. This is Chuck, Chuck calling us from San Francisco.

CHUCK: Hi. It would seem to me that reducing exposure to antibiotic-resistant bugs would be a real health benefit. And if livestock are not given antibiotics, then my understanding is that would reduce the number of these bugs that we're all exposed to. So that would seem like a real substantial benefit to organic food.

AUBREY: You know, certainly, this is a public health issue. I think for the purposes of this study, what we have here is, as I've mentioned, there's only so many human studies looking at clinical outcomes, meaning how did, you know, like how did eating organic food or how did the lack of these resistant bugs translate into any clinical effect on people? And because we don't have a lot of studies like that, it's a harder question for researchers to answer. But I certainly hear your point.

CHUCK: I thought that there were studies showing that giving antibiotics to livestock was responsible in part for the prevalence of these resistant bugs?

AUBREY: There are some studies. And I think the answer is that they are small and they point in different directions. And I don't know how many, if any, were included in this meta-analysis.

CHUCK: Was there studies about people's belief? How many people really think that they're getting health benefits and how many are doing it for the other reasons?

AUBREY: You know, that wasn't part of what these researchers did. The researchers - one researcher on the study at Stanford told me that her motivation was - she's also a medical doctor, a clinician who sees patients. And she says, look, people come in asking all the time, is organic better? Should I pay the extra money for it? And she was curious, so she dove into the literature that way. But nothing in the study tried to ask people what their motivations were.

CONAN: It seems more a subject for the Pew people than the Annals of Internal Medicine.

AUBREY: Right.

CHUCK: What we do hear in - when the media presents us with this story, it's always people think they're getting health benefits. I wonder - I think maybe people don't think that so much.

AUBREY: That's an interesting point. You may be right.

CHUCK: Thanks very much.

CONAN: Thanks for the call, Chuck. And it's interesting, he's talking about meat. Is the same certification organic for meat as it is for fruit and vegetables?

AUBREY: Well, actually - so the definition for fruit and vegetables is that it's grown without the use of most synthetic pesticides and synthetic fertilizers. And the definition for organic meat, poultry, eggs and dairy is that they - these products come from animals that are given no antibiotics or growth hormones.

CONAN: So different standards but the same definition?

AUBREY: Right.

CONAN: There are other labels - free range. There's all kinds of claims.

AUBREY: Oh, yeah.

CONAN: Boy, it's really hard to figure this out.

AUBREY: Right. You know, I think that the reason why the study has created such a conversation at so many water coolers and led to so many interesting controversial headlines is exactly to this point, that this is complicated. You know, organic is not the only dividing line here. And this is something that people may have to think about a little bit more.

CONAN: And you've talked about the research that's going into nutrition and making foods more nutritious. This is, again, separate from the idea of whether something is conventionally grown or organic.

AUBREY: That's exactly right. For instance, you can breed. You can comb through, you know, the existing seed bank. You can look at different varieties of, for instance, potatoes or corn. You can find variability in the nutrients there. So you can select for the ones that have the highest level of nutrients and grow those. So researchers are doing a bit of that. And, right, again, the dividing line there is not organic versus conventional.

CONAN: But if you did that, how do you market that?

AUBREY: Well, this begets a very interesting question because right now, how are farmers paid, right? By the - how we buy food, we buy it by the pound, right? So there would have to be a way in which consumers would, A, know about the nutrient level and food and, B, have a system for paying. And that becomes very complicated.

CONAN: There's a system to market organics that has grown up over the decades now.

AUBREY: Right.

CONAN: There is no system for this, as yet.

AUBREY: That's right.

CONAN: Interesting comment from Sarah by email: One thing I haven't heard mentioned in any of the stories on this study is the human rights angle. Part of the reason I eat organic is because I prefer to support farmers who do not expose their workers to large amounts of synthetic fertilizers. The residue on a tomato might not be enough to harm me, but constant exposure to large amounts of those chemicals can't be good. So are there standards about exposure? I assume there are.

AUBREY: Yeah. There are also standards for entry when you can get into a field after it's been sprayed. Those were developed with farm worker safety in mind. But the point she makes is a really important one, and I've heard that from a lot of folks that, look, you know, this is better for farm workers if they're not exposed to levels of synthetic - high levels of synthetic pesticides over a lifetime.

CONAN: Allison Aubrey, thanks very much for your time today.

AUBREY: Thank you.

CONAN: NPR science correspondent Allison Aubrey with us here in Studio 3A. Tomorrow, the sometimes difficult conversations doctors have with their patients about, well, not only eating healthy, but drinking healthy and smoking healthy, which is not smoking at all. Join us for that conversation. It's the TALK OF THE NATION from NPR News. I'm Neal Conan in Washington.

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