Is organic food really better for you?
April 21, 2011 11:06 AM   Subscribe

Is there a scientific consensus—ideally based on controlled, peer-reviewed, longitudinal, independently replicated studies—that an organic diet is healthier than a non-organic diet?

It seems like a reasonable idea, but I'd like to see the evidence. People get very emotionally invested in the organic food phenomenon, and a lot of its champions are also into alternative medicine and other pseudoscience, which is a big red flag.

Please note: I am not asking for your opinion on this question. I am not asking for assurances that such studies exist. I am looking for specific links to specific studies. (Feel free to summarize or comment on those studies, of course.)

I'm not challenging organic food, or trying to debunk anything. I do buy a lot of organic produce—I think the environmental benefits, at least, are clear. I just want to see the evidence for the claim that it's healthier.

Just one example: This article mentions a meta-analysis showing that nutrient levels are not significantly higher in non-organic foods, but it doesn't tell me where to find the actual study. Does anyone know?

Nutrients aren't the only factor, of course—studies could measure longevity, rates of cancer or coronary disease, whatever. Meta-analyses are of particular interest.

posted by ixohoxi to Science & Nature (21 answers total) 15 users marked this as a favorite
Actually, this (PDF) appears to be the study mentioned in the Mayo Clinic link.
posted by ixohoxi at 11:11 AM on April 21, 2011

The same researchers have a more recent review on health effects of organic foods generally:

From a total of 98,727 articles, we identified 12 relevant studies. A variety of different study designs were used; there were 8 reports (67%) of human studies, including 6 clinical trials, 1 cohort study, and 1 cross-sectional study, and 4 reports (33%) of studies in animals or human cell lines or serum. The results of the largest study suggested an association of reported consumption of strictly organic dairy products with a reduced risk of eczema in infants, but the majority of the remaining studies showed no evidence of differences in nutrition-related health outcomes that result from exposure to organic or conventionally produced foodstuffs. Given the paucity of available data, the heterogeneity of study designs used, exposures tested, and health outcomes investigated, no quantitative meta-analysis was justified.


From a systematic review of the currently available published literature, evidence is lacking for nutrition-related health effects that result from the consumption of organically produced foodstuffs.
posted by grouse at 11:15 AM on April 21, 2011 [1 favorite]

Thanks, grouse—that is helpful.

The rest of you: I'm not asking about other possible benefits of organic food (which, as I said, I tend to agree with). I'm also not asking about other dietary strategies, such as whole food vs. processed food.

I am asking about:

specific scientific studies
—which demonstrate (or refute) the alleged health benefits
—of organic food

One of the six comments here answers that question. The rest do not. Sorry if I sound grumpy, but this is exactly the sort of thing that led me to post this question.
posted by ixohoxi at 11:29 AM on April 21, 2011 [4 favorites]

This Organic food 'no healthier' than conventional produce, reveals watchdog news story made the rounds in 2009; that one says "The latest study was carried out for the FSA by researchers at the London School of Hygiene & Tropical Medicine," for what that's worth for your Googling. Holy derails already
posted by kmennie at 11:29 AM on April 21, 2011

I choose organic foods because I can be more confident about the ingredients and materials involved in its production, whereas I do not have that confidence in conventional foods.

The federal "Organic" standard blanket prohibits any non-organic (literally organic) or synthetic ingredients or materials from being included in Organic foods. Any new ingredient or material has to be individually submitted, reviewed, expert opinions and research are solicited, etc, before it is allowed into Organic-labelled foods.

Food that is not certified Organic falls under the FDA.

Here is a report from the investigation done into the FDA's (lack of) regulation for food ingredients, done by the US Government Accountability Office: FDA Should Strengthen Its Oversight of Food Ingredients Determined to Be Generally Recognized as Safe (GRAS)

To summarize, the FDA has a determination for food ingredients called "Generally Recognized As Safe." Let's say a company comes up with a new ingredient, Ingredient X. They are going to put it into all of their breakfast cereals. Voluntarily (the FDA does not require it), that company hires its own scientists to conduct its own study about whether that ingredient is GRAS. The company then voluntarily tells the FDA that they are putting this new ingredient into their cereal, and that the food is GRAS. The FDA says "Okay, got it." Now that ingredient is on supermarket shelves. The FDA does not have its own scientists look at that ingredient before or after it goes onto shelves, unless/until there is a gigantic outcry from consumers or independent researchers questioning its safety. The FDA does not monitor the procedures that companies use to conduct their GRAS studies or make the GRAS determination. Companies can put new ingredients in food without even telling the FDA that they are doing so. Those companies can even put a shiny sticker on the cereal box extolling the virtues of Ingredient X, the new wonder ingredient, virtues that the FDA will never verify.

So in essence, the FDA has no idea what companies are putting into their foods.

That does not necessarily mean that organic food is more healthful, just that there is a higher potential for dangerous and unhealthful things to be in conventional foods. I have to trust that the National Organic Standards Board is not corrupt (which is sort of not the case anymore) and that they are performing ingredient reviews adequately. But at least someone is monitoring the ingredients that are in organic food (every ingredient that they are requested to review, and the review process, is online). Because no one is paying attention to what is in conventional food, except the companies trying to sell it to you.

On preview, yes, addition through subtraction, as dflemingecon puts it.
posted by thebazilist at 11:36 AM on April 21, 2011

Here is a 2009 systematic review of the literature on the nutritional quality of organic food.

Conclusions: On the basis of a systematic review of studies of satisfactory quality, there is no evidence of a difference in nutrient quality between organically and conventionally produced foodstuffs. The small differences in nutrient content detected are biologically plausible and mostly relate to differences in production methods.

Here is another (2010) systematic review by the same authors:

Conclusion: From a systematic review of the currently available published literature, evidence is lacking for nutrition-related health effects that result from the consumption of organically produced foodstuffs.

These are all pretty recent systematic reviews of the literature, so they may fairly represent the literature as a whole - though they are only things I found with some very quick database searching.

Here is a "Review on the main differences between organic and conventional plant-based foods."

It appears that the intake of organic foods leads to some advantages, such as the ingestion of a higher content of phenolic compounds and some vitamins, such as vitamin C, and a lower content of nitrates and pesticides.

posted by googly at 11:45 AM on April 21, 2011

Well, I thought the fetal development thing counted as "health effects", but I get what you're looking for. First page of Google Scholar results for "organic food" found this:
A limited number of studies have compared the nutrient compositions of organically- and conventionally-produced crops, with a very small number of studies that have compared animal products (meat, milk and dairy products) produced under the two agricultural systems. Very few compositional differences have been reported, although there are reasonably consistent findings for higher nitrate and lower vitamin C contents of conventionally-produced vegetables, particularly leafy vegetables.
And on page 2 of the results, this, though only the abstract is available w/o payment:
Although there is little evidence that organic and conventional foods differ in respect to the concentrations of the various micronutrients (vitamins, minerals and trace elements), there seems to be a slight trend towards higher ascorbic acid content in organically grown leafy vegetables and potatoes. There is also a trend towards lower protein concentration but of higher quality in some organic vegetables and cereal crops. With respect to the rest of the nutrients and the other food groups, existing evidence is inadequate to allow for valid conclusions. Finally, animal feeding experiments indicate that animal health and reproductive performance are slightly improved when they are organically fed.
posted by statolith at 11:47 AM on April 21, 2011

Food that is not certified Organic falls under the FDA.

Umm.. what? Last I checked any fresh food such as fruit, vegetables, meat, dairy, etc. was dealt with by the USDA regardless of whether it is labeled "organic" or not. Please be careful using blanket statements.
posted by Mister Fabulous at 11:48 AM on April 21, 2011 [2 favorites]

[Bunch of comments removed. Please try and answer the question asked; this is not a general chat session.]
posted by cortex (staff) at 12:04 PM on April 21, 2011 [4 favorites]

There is no evidence, i.e. published research, that an organic diet is more healthful in humans than a conventional diet. If there were, one could find it easily via PubMed.
posted by hammerthyme at 12:15 PM on April 21, 2011

In The Ominivore's Dilemma Michael Pollan references several studies that are suggestive, mostly in connection to organic free-range eggs. He admits that they aren't conclusive, but looking through his references might lead to some interesting studies on the subject.
posted by ldthomps at 12:20 PM on April 21, 2011

As hammerthyme mentioned, PubMed is a great place to look if you want scientific, peer-reviewed research. Start typing "organic" and lots of search suggestions come up. I picked "organic food vs. conventional food" and got a promising bunch of hits.
posted by statolith at 12:43 PM on April 21, 2011

Overall, the results show that organic management and fertilization have a positive effect on the accumulation of certain beneficial minerals and phenolic compounds in eggplant and that organically and conventionally produced eggplants might be distinguished according to their composition profiles. J Agric Food Chem. 2010 Jun 9;58(11):6833-40.
posted by statolith at 12:45 PM on April 21, 2011

Seconding dflemingecon on the fact that there are two issues here.

First, there is a hypothesis that plants grown without pesticides tend to grow up more... hearty, or filled with nutrients, or something, because they need to do so in order to survive without artificial help. The thought is then that these plants might actually be better for you, thanks to all their extra nutrients. The reviews folks have listed here have addressed this point, and not shown any big difference.

Second, there is the question of whether the chemicals used in non-organic food are themselves harmful. I'm sure you'll find plenty of research if you look for particular chemical used in food production, and health hazards that may result. It's just that it's too broad to say "are chemicals in my food harmful", because the answer depends so much on which chemicals you are talking about. You may be able to find reviews that talk about health effects of certain groupings of chemicals commonly encountered by people with, say, a typical American diet, but I'm imagining the range here is still too broad.
posted by wyzewoman at 12:49 PM on April 21, 2011 [1 favorite]

Since no one linked to it yet, here's a good read over at Science-Based Medicine.
posted by pjaust at 1:03 PM on April 21, 2011

I thought I posted something... maybe it was removed, but here's some more information I just dug up:
Children exposed to pesticides in the womb are more likely to have measurable problems with intelligence, memory, and attention, three new studies show.

The pesticides in question, a class of chemicals called organophosphates, have long concerned both scientists and regulators because they work by irreversibly blocking an enzyme that’s critical to nerve function in both bugs and people.

Even at relatively low levels, organophosphates may be most hazardous to fetuses and young children, where healthy brain development depends on a carefully orchestrated sequence of biological events.
From WikiPedia:
Chronic fatigue is common amongst those who consider their health is affected by pesticides and research from 2003 suggested there was an association between exposure to organophosphates and chronic fatigue symptoms.[2]

A 2007 study linked the organophosphate insecticide chlorpyrifos, which is used on some fruits and vegetables, with delays in learning rates, reduced physical coordination, and behavioral problems in children, especially ADHD.[3]

A 2010 study has found that organophosphate exposure is associated with an increased risk of Alzheimer's disease.[4]
Personally, I find it odd that anyone would believe that spraying your food with poison that has common components of nerve gas could not have a detrimental effect on your health. And I'm not sure anyone doubts that food without these chemicals -- call them organic, or pesticide free -- are much better for you than food which has been soaked in those chemicals.
posted by notion at 1:39 PM on April 21, 2011

I find it odd that anyone would believe that spraying your food with poison that has common components of nerve gas could not have a detrimental effect on your health.

I don't doubt that it could have a detrimental health on my health. I'm just asking to see evidence that it actually does. There's a difference.
posted by ixohoxi at 1:57 PM on April 21, 2011 [3 favorites]

Are those three studies not good enough?
posted by notion at 2:56 PM on April 21, 2011

I did not say that. They may or may not be good enough. I intend to review them, and I thank you for posting them. (Although, honestly, I can type "organic" into PubMed or Google Scholar or Wikipedia as well as anyone else—and a couple of isolated studies never proves anything conclusively. I think I asked my question poorly.)
posted by ixohoxi at 3:21 PM on April 21, 2011

[folks, OP is asking about scientific consensus, not what you personally think is maybe true about organic food.]
posted by jessamyn (staff) at 8:25 PM on April 21, 2011 [2 favorites]

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