Apples & oranges in news coverage of the organic food study?

Photo credit: USDAgov via Flickr

There’s discussion around the globe today about a Stanford study that concludes that fruits and veggies labeled organic were no more nutritious than conventional foods which are less expensive.

Andrew Holtz, one of our HealthNewsReview.org reviewers, gave me permission to quote what he wrote on a journalists’ listserv.:

“The stories I’ve seen in the local media here fail to make clear
distinctions between what the Stanford researchers measured
(nutrients, bacteria levels and pesticide residue) and what many
proponents of organic practices talk about (concerns about effects of
pesticides on the general environment and farm workers, whether
routine use of antibiotics increases the risk of resistance, and so on).

Too many stories lead with a summary statement that the Stanford
meta-analysis failed to find that organic foods are “healthier”
without being clear about how the researchers and other sources
defined the term. The mismatched comments of experts discussing
different topics is bound to leave people confused.

Oh… and my favorite quote in a local story was from a dietician who
said: “Nutritionally there’s no greater value between organic or
inorganic produce.” I guess she shops at a market that offers lumps of
coal in the produce section.”

The Behind the Headlines project on the NHS Choices website did its usual thorough review.  Excerpts:

“Ultimately, the findings should be interpreted with some caution. There was a high level of variation between the studies in terms of the methods used, which makes the results of this review less reliable. It is also worth noting that few studies looked at relevant health effects and the studies ran for no longer than two years. This means no conclusions about long-term health benefits of organic foods can be drawn from this research. …

Overall, this systematic review provides some limited evidence of the differences in the health effects of organic and conventional foods. The authors do note that results should be “interpreted with caution” due to the high variation between the included studies. They note these differences may be due to soil type, storage practices and variation within organic practices.

There are some additional limitations to this review. Some of the human studies had very small samples which ranged from six to 6,630 people. In addition, none of these studies ran for longer than two years, which means conclusions about the long-term health benefits of organic foods cannot be drawn. The authors also note that some of the included field studies may not reflect real-world organic practices.

The researchers do suggest that a more effective method of assessing the relative benefits of “organic verses conventional food” would be to carry out a cohort or randomised controlled study. But these types of studies would be both very time consuming and expensive.

(One of the researchers) added when discussing the research that, “if you look beyond health effects, there are plenty of other reasons to buy organic instead of conventional”. “

(Photo credit:  USDAgov via Flickr.  Creative Commons)