Nutritional and Health benefits of Organically Grown Food?

I recently read a commentary  by Dominic Lawson, in the Times of London Sunday edition, entitled “Organic Food is Just a Tax on the Gullible.He was referring to  a couple of systematic reviews (health benefits and nutritional content) that suggest there are no measurable health benefits an no meaningful nutritional superiority associated with organically produced food .  The studies and the commentary add some useful detail to my previous comments about nutrition myths, and they illustrate nicely the seldom-appreciated complexity of making sound decisions about producing food, whether for animals or humans.

Now I’ll admit to a certain sympathy with organic food production, particularly as it seems likely to be less harmful to the environment than conventional industrial agriculture. And I have no doubt that the economic incentives of the agriculture industry lead to just as much malfeasance as those in the pharmaceutical game, or really any other area of economic activity. I believe we now produce more food, of better quality, more efficiently in terms of calories per acre that ever before, and that is itself a good thing, at least for our health as individuals and as a species. However, this increased production comes at a cost, and the use of fossil fuels and pesticides has consequences we must be mindful of.

Nevertheless, I believe in applying the same standards of evidence to all scientific claims, including those I personally find appealing. And I have been skeptical in the past of the nutritional and health claims of organic food proponents, which seem to be based more of the naturalistic fallacy  than on any evidence I’m aware of. A reader here suggested I had missed this evidence: “there are increasing numbers of studies documenting that (certified) organic food is more nutritious than conventional (non-certified organic food). They find significantly more minerals, vitamins, antioxidants in most all foods researcher look at.” Unfortunately, the person never responded to my subsequent request for details on these studies.

The first of the reviews Lawson comments on examined the literature from 1958-2008 and found only 11 studies that addressed the question of health benefits from organically produced foods or specific food ingredients. Of these, only 3 studies met the a priori defined criteria for methodological quality. The authors concluded, ” because of the limited and highly variable data available, and concerns over the reliability of some reported findings, there is currently no evidence of a health benefit from consuming organic compared to conventionally produced foodstuffs.” Clearly, this study does not definitively show that there are no health benefits to organically produced foods. But it does show that there is no high quality evidence for such benefits in the literature, which leaves the burden of proof squarely on those who make claims for the health benefits of eating organic foods.

The second study reviewed the literature for the same period, and did slightly better in terms of finding high quality studies. Of over 3000 studies examined, 55 met the quality standards. Based on these, the authors concluded:

“No evidence of a difference in content of nutrients and other substances between organically and conventionally produced crops and livestock products was detected for the majority of nutrients assessed in this review suggesting that organically and conventionally produced crops and livestock products are broadly comparable in their nutrient content. The differences detected in content of nutrients and other substances between organically and conventionally produced crops and livestock products are biologically plausible and most likely relate to differences in crop or animal management, and soil quality. It should be noted that these conclusions relate to the evidence base currently available, which contains limitations in the design and in the comparability of studies. There is no good evidence that increased dietary intake, of the nutrients identified in this review to be present in larger amounts in organically than in conventionally produced crops and livestock products, would be of benefit to individuals consuming a normal varied diet, and it is therefore unlikely that these differences in nutrient content are relevant to consumer health.”

These two reviews have been criticized, not surprisingly, by organic food producers, primarily for their exclusion of studies which support the producers’ claims. Ben Goldacre has already responded to the substance of these criticisms. Clearly, these two reviews cannot not be the final word on the subject. They strongly suggest that when the scientific literature does not support the claims that organically produced food is healthier or more nutritious than conventionally produced foods, but they also show that the evidence is sparse and of poor quality, so we must keep an open mind on the subject. And, of course, none of this bears on the other potential benefits of organic agriculture, including decreased environmental harm and subjective benefits such as better tasting food. These are themselves issues which ought to be investigated in a rigorous way.

Finally, Lawson’s commentary made what I thought was a critical point, nicely illustrate by an anecdote that is humorous, rather than tragic, only because it ended happily. I’ll let him tell it:

“A few years ago my wife decided we should have an entirely organic vegetable garden. To this end she refused all man-made fertilisers [sic] and ordered a truckload of pigeon droppings. What could be more natural? Neither was there anything unnatural in the germs I inhaled through the spores of our organic manure, thereby contracting psittacosis. This developed into “atypical” pneumonia, which was of course resistant to all standard antibiotics. Had a hospital doctor not guessed the cause and put me on a drip with the appropriate drugs – ooh, chemicals! – I could have become a fatal casualty of the organic movement. Obviously my wife might have ordered cow manure rather than pigeon poo[p]; then I could have been felled by E coli instead.”

This is a powerful illustration of a concept promoters of CAM often ignore; every choice has an array of costs and benefits that have to be evaluated and balanced. Vaccines do sometimes cause harm, but to a far lesser degree than the harm of not using them appropriately. And there may be benefits to reducing the use of chemical fertilizers, but one cannot just blithely follow the naturalistic fallacy and assume that organic fertilizers are always better. This sort of cost benefit analysis is always difficult, tedious, and fraught with uncertainty, and it lacks the appeal of simplicity, but it is a crucial part of making the best decisions about medicine, agriculture, or any other complex endeavor.

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7 Responses to Nutritional and Health benefits of Organically Grown Food?

  1. Bartimaeus says:

    It does seem that any evidence for increased nutritional benefits for organic food is just about non-existent. I agree though that there may be other benefits to less intensive agriculture. These include, when at their best, reduced use of non-renewable resources (debatable with some models of distribution), more humane conditions for livestock, and better habitat for wildlife with smaller, more varied fields and pastures. I keep chickens for eggs, and use the manure to fertilize the garden. I also eat less store bought meat by applying for population control (antlerless) Elk hunts. The local elk population is probably too high, probably because most of their natural predators (wolves and grizzlies) have been locally extinct for 80-90 years. Some may not agree with that choice, but at least I know how that animal lived, and am willing to take personal responsibility for the way it died. One of my ranch-raised classmates said once during a discussion that no one should eat something they were not willing to kill themselves. I think that that type of personal relationship with the animals people raise and a concern and responsibility for the animal’s welfare, even if the end result is steaks in the freezer is lost in factory farming.

  2. Rita says:

    “Under the acts a local authority is required to maintain an “adequate provision” of land, usually a large allotment field which can then be subdivided into allotment gardens for individual residents at a low rent. ……. The council has a duty to provide sufficient allotments to meet demand. The total income from allotments was £2.61 million and total expenditure was £8.44 million in 1997″.
    From the Wikipedia allotment article – Note that councils in the UK MUST provide allotments – so in principle, everyone can grow at least some of their own veggies in whatever style they wish. Is there similar provision in the US, I wonder?
    I agree with skeptvet that there is an intuitive appeal about organic veg. which may well not stand up to scientific analysis, and that many other factors come into play. But one of those factors is shelf life and transport (an ecological problem in itsef). Fruit and veg do deteriorate (do they not?) with time away from source – so local/home grown stuff (which probably has more chance of being “organic”), could measure up better than”shop-bought” just on those grounds, regardless of method of cultivation…….
    I can’t comment on the animal front, because I’m vegan, for purely ethical reasons. However, I was interested to see Bartimaeus’ quote: “One of my ranch-raised classmates said once during a discussion that no one should eat something they were not willing to kill themselves”.
    This used to be advanced, very properly, IMO, in arguments against capital punishment – anyone who thinks CP is correct sould be prepared to have the role of executioner allocated by ballot to any member of the community – themselves, their children, aged aunt, whatever. The problem, as the use of this argument for dispatching one’s own meat shows, is that people – or at least some people, (and what makes the difference?!) get incredibly hardened incredibly quickly………more cognitive dissonance!

  3. Bartimaeus says:

    Interesting comment Rita, there are some community gardens to varying degrees in the US, but no regulatory requirement to provide them anywhere as far as I know. There does seem to be an increasingly large number of people who do have space to grow a garden and/or raise some backyard livestock in many parts of the US.

    In my experience (admittedly a limited sample size) most people who are involved in raising and caring for animals on a relatively small scale, people doing research involving animals and even most hunters are not as “hardened” as you might think, although I’m not sure how to measure that. and often have a much more profound respect and understanding of the animals that they do kill than many urban/suburban dwellers that have little or no contact with live animals other than a pet.

    As to the suggestion of cognitive dissonance, while that may play a part for some people, “I think you’ll find that it’s a bit more complicated than that” to quote Ben Goldacre.

    I never grew up hunting, and was opposed to hunting for many years, but after a lot of time spent in the wilds observing wildlife, and reading Aldo Leopold’s writings about this part of the world, I do not think all hunting is bad or unethical anymore. To Quote Leopold;

    ” I now suspect that just as a deer herd lives in mortal fear of It’s wolves, so does a mountain live in mortal fear of it’s deer. And perhaps with better cause, for while a buck pulled down by wolves can be replaced in two or three years, a range pulled down by too many deer may fail of replacement in as many decades.
    “So also with cows. The cowman who cleans his range of wolves does not realize that he is taking over the wolf’s job of trimming the herd to fit the range. He has not learned to think like a mountain. Hence we have dustbowls, and rivers washig the future into the sea.
    “We all strive for safety, prosperity, comfort, long life, and dullness. The deer strives with his supple legs, the cowman with trap and poison, the statesman with pen, the most of us with machines, votes, and dollars, but it all comes to the same thing: peace in our time. A measure of success in this is all well enough, and perhaps is a requisite to objective thinking, but too much safety seems to yield only danger in the long run. Perhaps this is behind Thoureau’s dictum: In wildness is the salvation of the world. Perhaps this is the hidden meaning in the howl of the wolf, long known among mountains, but seldom perceived among men.”

    I would hate to see the elk disappear, and hope for the return of the wolf, but until then, we humans will need to hunt some of the elk. I think my point in all this is that there are many answers to some of the same questions. While some choose to avoid meat completely, others may take different approaches to the issue by raising or hunting their own meat. These too can be positive solutions, even if they are not the choice you would make.

  4. Rita says:

    I don’t think this is the place to go into all the hunting stuff – needless to say, I have heard all these points discussed back and forth a million times – my point about people taking responsiblity for capital punishment was not really on topic, either, so I apologise for going off the very interesting thread, which was the quality of so-called organic foods – is this made a selling point in pet foods in the US? it seems to be here (Spain).

  5. skeptvet says:

    Certainly int he U.S “organic” is seen as synonymous with “healthy” by many people, so it’s a convenient thing to use in advertising a food. It’s not quite as meaningless as “natural,” but it still doesn’t really say anything useful about the quality of the food itself, even if it might have relevance to deciding what kind of agriculture on wishes to support.

  6. v.t. says:

    Penn & Teller did a stint on this recently, you could find a video on youtube. Pretty interesting when organic buffs couldn’t tell the difference between an organic piece of fruit or veggie to a non-organic one, and most all of the subjects said the non-organic tasted so much better.

  7. Pingback: Canine Nutrigenomics by Dr. Jean Dodds: Science as Windowdressing | The SkeptVet

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