Infinite Blogging

Tales of love, fertility and nourishing food.

Is organic food higher in nutritional quality than conventional food? August 31, 2009

Filed under: Environment,Food,Growing,News and Blogs — Annette @ 1:32 pm

Drumroll, please.

And the answer is…probably not.

The “first published systematic review investigating differences in nutrient content of organically and conventionally produced foodstuffs” was recently published. This has been a hot and controversial topic for a long time, so I’m glad someone finally did a good, thorough review.

They did a review – not a lab study – but a review of the existing literature to see what the entire mass of published literature on the topic has to say. So instead of saying, “this study says this” and “this study says that,” they looked at what the whole body of research says when combined.

Their conclusion?

In an analysis that included only satisfactory-quality studies, conventionally produced crops had a significantly higher content of nitrogen, and organically produced crops had a significantly higher content of phosphorus and higher titratable acidity. No evidence of a difference was detected for the remaining 8 of 11 crop nutrient categories analyzed.

…Analysis of satisfactory quality crop studies found no evidence of a difference in 8 of the 11 nutrient categories (vitamin C, phenolic compounds, magnesium, potassium, calcium, zinc, copper, and total soluble solids) (Table 1). Nitrogen contents were significantly higher in conventionally produced crops, and contents of phosphorus and titratable acidity were significantly higher in organically produced crops.

…Differences that were detected in crops were biologically plausible and were most likely due to differences in fertilizer use (nitrogen and phosphorus) (3) and ripeness at harvest (titratable acidity) (16). It is unlikely that consumption of these nutrients at the concentrations reported in organic foods in this study provide any health benefit.

…The current analysis suggests that a small number of differences in nutrient content exist between organically and conventionally produced foodstuffs and that, whereas these differences in content are biologically plausible, they are unlikely to be of public health relevance. One broad conclusion to draw from this review is that there is no evidence to support the selection of organically produced foodstuffs over conventionally produced foodstuffs to increase the intake of specific nutrients or nutritionally relevant substances.

Now, clarification: I do support organic agriculture practices. I am not dogmatic about it, but I think overall we would probably all be better off if we didn’t have as many pesticides and synthetic fertilizers being sprayed around. However, there is a difference between supporting organic for environmental reasons (pesticides, fertilizers, environmental impact, etc.) and supporting it because you think you’re getting more nutrients from organic food.

The researchers even clarify this themselves:

The outcome was restricted to the nutrient and nutritionally relevant content of foodstuffs. We did not address differences in contaminant contents (eg, herbicide, pesticide, or fungicide residues) or the possible environmental consequences of organic and conventional agricultural practices because this was beyond the scope of our review.

I don’t think there’s much of a question about organics containing less pesticides, etc. than conventional produce. But the point here is that you’re not getting more calcium or magnesium from organic produce than you would from conventional produce.

I don’t think we can necessarily call this “case closed,” because science is always evolving with more recent research. But I think we now have some good research to put behind our informed decisions.


9 Responses to “Is organic food higher in nutritional quality than conventional food?”

  1. mamaterri Says:

    I think a lot of people make the assumption that “organic” means “more nutritious.” They don’t realize that it simply means grown without use of chemicals. Many big-name organics are grown with the same “factory farming” methods of non-organics, meaning that there is little or no concern about the nutrient level of the soil beyond what is necessary to make the plants grow enough to harvest and sell. To get nutrient rich produce, farmers must use methods that build up and maintain the nutrients in the soil. Seems like that would be a given, but it’s not.

  2. rakkav Says:

    @mamaterri: According to the sources I’ve seen, organic farming worthy of the name (and certified as such by at least one agency) requires much more than just the avoidance of chemicals. It requires a whole way of dealing with agriculture, including practices that are good for the soil. Those sources I’ve seen also warn, as you do, that not everything that calls itself “organic” is worthy of the name; that’s why it’s worthwhile to check for certification as a “sorting criterion”.

    @annette: With regard to the article you cite, here are two rebuttals worth noting:

    It’s worth going back to THE PLAIN TRUTH in the 1960’s (and maybe even the 1950’s), as well as the AC Agricultural Dept. Reports, for even more information showing the superiority of properly raised organic food for both the food itself and the environment.

  3. Annette Says:

    As much as I respect The Plain Truth, I am skeptical of studies that are decades old. There’s a reason reviews are often limited to the last 50 years, partly because studies prior to that are often no longer relevant.

    Also, I read the research article and although I didn’t heavily scrutinize their methods, they seemed to have very good reasons for excluding the studies they did. A review isn’t worth a whole lot if it reviews a whole bunch of poor quality studies.

    Again, do you see that we’re talking here about NUTRIENTS and not environmental impact? 🙂

  4. Annette Says:

    I don’t understand who the “they” is in the second article:

    “The study appears to say absolutely nothing negative about organics, despite valiant attempts by the media to create sensational headlines. In the data reviewed, they found that organic food was superior to non-organic food in the measurements of beta-carotene by 53 percent and flavonoids by 38 percent, as well as in the amounts of phenolic compounds, protein, copper, magnesium, phosphorus, potassium, sodium, sulfur and zinc, all of which are required to foster complete nutrition.”

    This type of information wasn’t in the review, so I’m not sure where he’s getting this from.

    • rakkav Says:

      Ah. You are saying that this set of claims isn’t stated in the review itself? Ostensibly, then, it would be in one of the studies reviewed. It would be well to know which one.

      Never again will I try to discuss a technical subject when my brain is as much on the fritz as it is right now.

  5. rakkav Says:

    The “they” would be the authors of the original study in question here — those doing the review in the U.K. What is unclear is precisely what sources they’re citing (which should be made clear in the original study).

    Why are studies that are 50 years old more suspect than modern studies? Testing methods have become more precise (less margin for error) and able to work with smaller samples, but the laws of chemistry and physics (which make nutritional testing possible) haven’t changed over that time. What has changed is that we now have more things to look for: not just vitamins, minerals and protein (on which the general trend of the studies hasn’t seemed to change much), but whole classes of substances we didn’t even know were important for human nutrition until recently.

    Mr. Hirshberg’s conflation of nutrition and pesticide/fertilizer use under the public health umbrella is puzzling, and perhaps by now he’s been called on it. But he seems to make that conflation because he realizes that the two issues shouldn’t be separated. Organic food worthy of the name only gets that way when the whole context of organic farming is in place, and two aspects (only two) are the avoidances of chemical fertilizers and pesticides.

  6. mamaterri Says:

    Rakkav, you used an important phrase, “organic farming worthy of the name”. Also as you said, unfortunately, not everything labeled organic is worthy of the name.

    As for studies, I tend to view recent studies with far more skepticism than I do older studies. It seems like every time we turn around, we hear about the results of studies being skewed in favor of those who funded the study. Perhaps it has always been this way, and I am naive to think older studies are less affected by who funded them. I personally do not believe that “pure science” exists in this “present evil age.”

  7. Michelle Says:

    I wonder if the findings would be similar when comparing organically and conventionally produced meat and dairy?

  8. Annette Says:

    They did look at “livestock products,” but said this was very limited because there were only 9 studies to compare. They didn’t find any difference between the two.

    I don’t know what the qualifications are to be “organic” when it comes to meat, but I wonder if there might be more of a difference if a study looked at grass fed vs. grain fed.

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