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Organic Food: Is It Better For You?

In 1952 Martin Gardner, who just passed away this week at the age of 95, wrote about organic farming in his book Fads and Fallacies in the Name of Science. He characterized it as a food fad without scientific justification. Now, 58 years later, the science has not changed much at all.

A recent review of the literature of the last 50 years shows that there is no evidence for health benefits from eating an organic diet. The only exception to this was evidence for a lower risk of eczema in children eating organic dairy products. But with so many potential correlations to look for, this can just be noise in the data.

Another important conclusion of this systematic review is the paucity of good research into organic food –- they identified only 12 relevant trials. So while there is a lack of evidence for health benefits from eating an organic diet, we do not have enough high-quality studies to say this question has been definitively answered. It is surprising, given the fact that organic food was controversial in the 1950s, that so little good research has been done over the last half-century.

It should be noted that we only recently had any rules in the US regarding the label “organic.” According to the USDA:

The Organic Foods Production Act (OFPA), enacted under Title 21 of the 1990 Farm Bill, served to establish uniform national standards for the production and handling of foods labeled as “organic.”

The definition of organic entirely relates to the method of production, no the final product. It involves three principles. One is sustainable farming that is optimal for the environment. That question is beyond the scope of this medical blog. Many people do advocate organic farming for this reason alone, and many of the principles of sustainable farming are being incorporated more generally into agriculture and animal husbandry.

The second principle is the establishment of an ecosystem, using cover crops, crop rotation, and other methods. Again –- I want to set aside the environmental questions and focus on the nutritional claims. Does organic farming result in produce that is more nutritious. There are different ways we can approach this question. One is addressed by the systematic review above –- can we measure a health advantage to eating an organic diet. The answer to that question, at the present time, is no. This could be due to the fact that there is no health benefit, or that any benefit is smaller than the studies currently available could detect. Long term modest health benefits are very difficult to detect with clinical trials, and it is therefore difficult to rule out such benefits, but at present there is no evidence of health benefits from an organic diet.

The second way to approach this question is to evaluate the food products themselves -– are they more nutritious. The most recent systematic review of the evidence concluded:

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.

There is also a recent study concluding that birds prefer seed that is conventionally produced over seed that is organically produced –- likely because conventional production methods result in a 10% higher protein content.

The third issue with organic food is what is not in or on them –- pesticides, hormones, and antibiotics. Here, again, we can take the same two approaches as with nutrition –- is there any evidence of a difference between organic and conventional produce, and is there evidence for a health benefit. There seems to be a consensus on the first question –- organic produce has less synthetic pesticides, and organic meat has less hormones and antibiotics than their conventionally grown equivalents. But is this safer for health? The review cited above is also relevant to this question, and essentially there is no evidence for greater safety of organic food over conventional food.

With regard to pesticides, it must also be noted that organic farming, while using methods to minimize pests and the need for pesticides, still use organic, rather than synthetic, pesticides. For example a rotenone-pyrethrin mixture is commonly used. Such pesticides are not as well studied as synthetic pesticides, often require more applications, and may persist longer in the soil. In fact the use of “natural” pesticides is nothing more than an appeal to the naturalistic fallacy –- there really is no evidence for superior safety, and they have not been adequately studied.

There is a recent study which has garnered a great deal of press linking organophosphates –- a type of synthetic pesticide –- to higher prevalence of ADHD. However, this is a preliminary observational study. While interesting, it really can only be used to justify further research, not any conclusions regarding the effects of organophosphates. (I discuss this article in more detail here.)

It does seem reasonable to minimize human exposure to pesticides. This can be accomplished, at least in part, however, by simply washing all produce thoroughly. I could not find any direct comparisons of organic produce to thoroughly washed conventional produce, but what evidence we do have suggests that residue levels are below safety limits and can be lowered further by washing. This is an area that does require continued monitoring and research, however.

Conclusion

Overall there does not appear to be any advantage for health to organic farming (sustainability and environmental effects being a separate issue). However, despite the fact that organic farming has been around for over 50 years, there is a surprisingly small amount of quality research available. The organic farming industry and popularity of organic products is growing. Organic products are more expensive, and questions remain about whether or not such methods would be adequate to supply our food needs. There may also be hidden health risks or unintended consequences to relying upon organic farming. There may also be benefits that have not been adequately documented. Therefore this is one area where I think it is reasonable to conclude more research is genuinely needed.

*This blog post was originally published at Science-Based Medicine*


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2 Responses to “Organic Food: Is It Better For You?”

  1. Marya says:

    What a great post! Dr. Novella makes the point that there is no evidence for the superiority of consuming organically produced foods over the conventionally produced ones in terms of health benefits. To arrive at this conclusion he relies heavily on a recent systematic review supported by the UK Food Standards Agency, which examined 12 studies, 8 of them in humans, 6 of which were RCTs and the remaining 2 observational studies. Because the article is available by subscription only, I could not access the whole paper. However, knowing what conducting clinical trials entails, I doubt that the 6 experimental studies followed the subjects for all that long. Perhaps not long enough to detect the benefit? Would love Dr. Novella to comment on this.
    Additionally, divorcing the potential direct health effects due to consumption of organic products from the effects of the production on the environment is a false dichotomy. The pesticides do not just stay on the skin of the produce, but get into our water supply; the antibiotics given to the animals in CAFOs do not just get into their meat, but also get into the water and produce resistant pathogens — there is plenty of work from the Netherlands to support the connection between agribusiness practices and human pathogen resistance emergence. Also, look at the staggering findings by the USGS about the contaminants found widely in our water supply and in what amounts.
    The monoculture model of conventional agribusiness also requires enormous amounts of petroleum for fertilizers and pesticides as well, a resource that is dwindling. And, perhaps most importantly, the impact of monoculture farming on the land itself is devastating, decimating arable lands and creating essentially sterile deserts which need centuries to recover.
    Having said all this, the mass-produced organic food business is not much more environmentally friendly than the conventional agribusiness, relying on monocultures and artificial fertilizing and pesticide management, as Dr. Novella aptly points out. Additionally, because it is concentrated in places remote from where it is consumed, its carbon footprint is still enormous. The really sustainable way to farm and eat, environmentally and human health-wise, is returning to small local farming, with a short distance from farm to table and a self-perpetuating cycle of earth’s nutrient consumption and repletion by a diverse biome, just like nature intended.
    My final sentiment is that, as people involved in healthcare of our nation, we must care about social and environmental justice. While these issues may fall more comfortably under the rubric of Public Health, doctors and nurses and other personnel at the bedside need to develop a greater appreciation for the context in which disease develops. This context includes healthy and sustainable food production and other social and environmental concerns.

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