Cookaholics Bulletin Board

In a moment of astonishingly weak scholarship, Stanford decided that a non-study which showed nothing in particular about organic foods merited a press release:

http://med.stanford.edu/ism/2012/september/organic.html

The headline and first paragraph seem interesting, but then you read into the article and discover that all the "researcher" did was collate other people's studies, many of which she admitted "were not very rigorous."

While I respect the effort which went into the collation, the opinions she forms based on it seem entirely unwarranted, and not a little self-justifying. Absence of evidence is not evidence of absence.

I thought the same thing...if you are merely reviewing bad studies, how is looking at a lot of them going to end up with a valid result? Weak indeed.

This study was done over 4 years and is a ‘meta-analysis’. The statistical analyses for this type of study are well-regarded and rigorous. The researchers are well-respected amongst their peers and it was published in a peer-reviewed journal, Annals of Internal Medicine.

“The Stanford team combed through thousands of studies to analyze the 237 that most rigorously compared organic and conventional foods. Bravata was dismayed that just 17 compared how people fared eating either diet while the rest investigated properties of the foods themselves.”

I wouldn’t ignore the conclusions just because you don’t agree with them.

Read the article, not the ‘news’. A summary may be seen here: http://annals.org/article.aspx?articleid=1355685 To read the full article would require a subscription though most hospitals will allow you to read it in their library.

I'm with Wino on this one. Meta-studies definitely have value; even if the underlying studies are flawed, across enough of them sometimes good conclusions can be had. Now CR points out some interesting limitations, but to be fair it is always possible to nit-pick studies; whether those limitations are fatal are what is important. Most studies have some truth.

And of course, even if the nutrition was the same, it doesn't mean the organic isn't better for you; pesticides might matter. I'd also point out that some foods may have significant differences in nutrition but don't fall in the organic/non-organic divide. A very good example is grass-fed beef. It is certainly possible to have corn-finished organic beef as well as non-organic grass-fed beef, but there are probably significant differences based on the feed, not whether it was all organic.

I'm ticked off at the brazen and exaggerated statements of one of the researchers. Compare:

"The published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods." (supported)

vs.

“There isn’t much difference between organic and conventional foods, if you’re an adult and making a decision based solely on your health.” (unsupported)

The latter is one of the researchers leaping to conclusions based on inadequate evidence, something I can't respect. For comparison, note that the benefits of Vitamin C in overcoming colds was first proven only a year ago; prior to that, researchers also said "Quantities of Vitamin C above the RDA has not been shown to have any effect on avoiding or overcoming illness."

It's also very sad that we live in a world where I can read someone's inflammatory summary of research for free, but the actual research costs $100.

Now, what the review does appear to have done is show the inadequacy of the research on organic food and health, and the lack of a clear definition of what "organic food" even is. Both of which are great pointers to where further research seems like a really good idea (along with the child pesticide thing).

This is also interesting from the abstract (thanks for link, wino): "scherichia coli contamination risk did not differ between organic and conventional produce. Bacterial contamination of retail chicken and pork was common but unrelated to farming method." You'd actually expect bacterial contamination to be a little higher for organic produce/meat, but apparently it's not.

I'm afraid that sometimes the summaries amount to link bait, which is shameful since most of the news will be written from the summary.

... correcting myself: "... but apparently there's no evidence that it is."

I don't really appreciate the implications of that comment. I am not "ignoring" anything "just because [I] don't agree with them." I have never assumed that organic food was more nutritious or less susceptible to pathogens.* In fact, I usually correct people who say they only use organic eggs so they don't get salmonella poisoning, because I have seen studies that find higher levels of salmonella and campylobacter among organic eggs from some farms.

It just seemed to me that a study of bad studies couldn't be good. I stand corrected. Just please don't assume I dismiss something because I don't agree with the conclusions. I am willing to change my view when provided compelling evidence or reasoning. FWIW, I don't purchase organic food because I think it's nutritionally superior - my concerns are the environmental damage caused by conventional farming and residual pesticides.


*I will admit to a sneaking suspicion that heirloom varieties of some veggies are nutritionally superior to those developed for industrial farming & shipping (regardless of growing method), but I'll wait for research confirming this before I spout off about it.

side rant here. Why do my grocery stores sell organic bananas in sealed bags so I have to buy 6 or 8, when the others are sold loose? We hate banana bread so it's a waste having that many bananas. Well, not really a waste per se, since my neighbour gets them and they love banana bread. But a waste for me.
Rant over.

Darcie, Wino,

I do think it's quite possible that there isn't any broad, across-the-board nutritional difference in primary vitamins in organic vs. chemical farming. Likely even. And organic advocates did themselves a big disservice by quoting that completely spurious "40% vitamin loss" figure for years.

Where I'd love to see studies to look for differences include:

• micronutrients (e.g. not A-E vitamins or major minerals)
• beneficial probiotic content (I would expect this to be a lot higher in organics ... but is it?)
• factory farmed vs. small-heirloom-farmed organics

For my own part, I often (but not always) buy organic produce because:

• it's usually better tasting
• it's what my grocer generally stocks
• good for the environment
• some expectations of better nutrition, despite studies

One of the other scary things the abstract mentioned is that pesticide content was "substantially different, but not above approved levels". So one thing which organic fans disagree with the FDA about is how much pesticide is safe in our diet. The organistimos may be wrong, but most of the studies on the subject have been funded by pesticide companies, so there's no good evidence either way that I've found.