Science of organic food – are they healthier?

Organic foods have been increasingly popular these days moving from local co-ops and farmer’s markets to large retail chains that specialize in organic foods (such as Whole Foods) to general large retail chains who dedicate portions of their produce sections to organic produce. Even dairy and meat sections of most supermarket chains have sections that contain organic products.

But what is the underlying science of organic food whatever the source? Is it healthier? Is it worth the additional cost? Is there some indication that farm productivity is higher in organic farms?

It’s time for a skeptical look at the cost and benefits of organic foods.

What are organic foods?

Organic foods are usually crops, meat or other animal products (milk, cheese, honey) which have been produced without the use of synthetic pesticides and fertilizers. Some people broaden that description to include genetic modification (or GMO or GM) along with certain preservation techniques such as food irradiation. In addition, some organic meats and animal products also state that they are produced without the use of antibiotics and growth hormones.

Organic farming was pioneered in the early part of the 20th century based on the unproven idea that chemical pesticides and fertilizers supposedly had a negative effect on flavors and nutritional values of foods. Over the years, organic farming has grown into a huge business based on the supposed health and flavor benefits, but also on the the potential benefits that organic agriculture may have on the environmental impact of agricultural chemicals. In addition, there is a lot of concern about the persistence of pesticides on our food sources.

The standards for what is or isn’t organic food is highly variable. Many governments usually set standards for foods to be legally sold as organic. In some countries, the regulatory role is taken on by non-governmental agencies. The Soil Association performs such a function in the UK, while the European Union sets its own rules for organic certification.

In the United States, the USDA does have a certification program for organic foods. (Editor’s note: because one reader repetitively and excessively whined  with pedantic legal verbosity about what constitutes organic foods, and because regulations are not the point of this article, I’ve deleted most of it–this article is about the science).

Organic foods have become a cultural icon in the developed world. About 58% of Americans prefer organic food to regular food, according to a 2011 Thomson Reuters-NPR Health Poll (pdf), about 34% are concerned about “toxins” in non-organic foods. A minority also believe they taste better and are better for the environment, there are broad reasons for preferring organic foods. Another poll in 2003 found that 68.9% of Vermonters believed that organic food was “healthier.”

The myths and science of organic foods

 

But, are those organic really better for you? Well, in an article in the  Annals of Internal Medicineconcluded that, using terms that you don’t find too often in scientific literature:

[infobox icon=”quote-left”]…the published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods.[/infobox]

In another systematic review of 50 years of research comparing the nutritional advantages between organic and non-organic foods, published in Clinical Nutrition, the researchers found that:

[infobox icon=”quote-left”]…evidence is lacking for nutrition-related health effects that result from the consumption of organically produced foodstuffs.[/infobox]

Finally, another systemic review, arrived at nearly the same conclusion:

[infobox icon=”quote-left”]…there is no evidence of a difference in nutrient quality between organically and conventionally produced foodstuffs.[/infobox]

All of these articles are systematic reviews, which are probably the pinnacle of peer-reviewed scientific research. In other words, they nearly represent the scientific consensus on organic foods.



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More science of organic food

 

Of course, nutritional quality isn’t the only reason to buy organic foods. The first review, mentioned above in the Annals of Internal Medicine, stated that “consumption of organic foods may reduce exposure to pesticide residues and antibiotic-resistant bacteria.” Not exactly a ringing endorsement, and the evidence overall was all over the place with regards to the supposed benefits to food safety:

  • Two studies included in the review reported significantly lower urinary pesticide levels among children consuming organic versus conventional diets. However, the studies made no indication whether there was any clinical significance–one of the hallmarks of evidence-based medicine.
  • The risk for contamination with detectable pesticide residues was lower among organic than conventional produce, but differences in risk for exceeding maximum allowed limits were small. Again, clinical significance was lacking.
  • On the other hand, studies of biomarker and nutrient levels in serum, urine, breast milk, and semen in adults did not identify clinically meaningful differences. Yes, I said that!
  • Estimates of differences in contaminant levels in foods were highly variable except for the estimate for phosphorus, which were significantly higher than in conventional produce, although not clinically so.
  • Escherichia coli contamination risk did not differ between organic and conventional produce.
  • Bacterial contamination of retail chicken and pork was common but didn’t differ between organic or non-organic farming methods. However, the risk of finding bacteria resistant to 3 or more antibiotics was higher in non-organic than in organic chicken and pork. This difference might be important if that bacterial contamination spreads to family members.
  • Only 3 of the human studies examined clinical outcomes, finding no significant differences between groups that consumed either organic or conventional foods for allergic outcomes (eczema, wheeze, atopic sensitization) or symptomatic Campylobacter infection.

In other words, there is some very slight evidence that the organic foods are safer. But mostly, the evidence was equivocal or nonexistent. Given the higher cost of organic foods, it’s hard to come up with a cost:benefit equation that is convincing, especially if you can’t develop a realistic clinical risk from small pesticide contamination. To be fair, some may argue no pesticides is the best level, an example of the appeal to nature logical fallacy.

But what if simply washing the fruits and vegetables removes most of the pesticides and other chemical contaminants? That reduces any risk that might be of concern with conventional produce. And since we are supposed to thoroughly cook poultry and pork, don’t we reduce the risk of bacterial contamination? If we can reduce the the minor risks of chemical and bacterial contaminations from traditional agricultural products, and we derive no known nutritional benefits from them, then why are we paying so much more for it?

Paying more for organic food

 

In general, organic foods are more expensive (sometimes significantly more expensive) than traditional foods. There are a few reasons why the prices are higher, some just market preference, which are really dependent upon person feelings.

  1. Taste. OK, this is totally subjective. Some produce comes from heirloom plants,  which are cultivars that were commonly grown during earlier periods in human history, but which is not used in modern large-scale agriculture. Many heirloom fruits and vegetables have kept their traits through, such as potato open pollination, while fruit varieties such as apples (red and green apples instead of black) have been propagated over the centuries through grafts and cuttings. They do have different flavors and textures that can be interesting and quite tasty. But they are expensive, and can only be found at local markets, some specialized supermarkets, and rarely off-season.
  2. Green. Some people believe that organic farming is better for the environment, and better for slowing climate change. However, in another high quality systematic review of conventional vs. organic agriculture, the authors found that “Our review and meta-analysis of yield data comparing organic and conventional agriculture showed that currently organic yields of individual crops are on average 80% of conventional yields.” In other words, organic farming is substantially less efficient than traditional farming.
  3. Support small farmers. Maybe. Again, the cost is going to be higher, and this does limit these foods to a certain economic class of people who can afford the food. Remember, large agribusiness does drive costs of food down, so that larger numbers of people can afford food, a critical consideration for those who think it’s critical to feed people.
  4. Evidence be damned, no chemicals are going into my kids. Don’t breathe then. What am I going to say to that? Some people want to reduce risk to near 0%. I guess in that case organic produce might do that. But how do you know that your produce is actually organic? Or that the fertilizer wasn’t contaminated with some type of manure that was infected with some obscure bacteria? Reducing risk to zero is impossible.

Summary

 

As Steven Novella says at Science-Based Medicine,

[infobox icon=”quote-left”]The recent review of organic vs conventional produce agrees with previous systematic reviews that there is insufficient evidence to conclude that organic produce is healthier or more nutritious that conventional produce. Despite the scientific evidence, the alleged health benefits of organic produce is the number one reason given by consumers for buying organic. This likely represents the triumph of marketing over scientific reality.[/infobox]

Yes marketing sometimes does triumph over real science. Big Tobacco has, for years, claimed that smoking was healthy, despite 50 years of real science that said “nope, it’s dangerous.” The current medical marijuana craze has no basis in science.

A lot of Big Agriculture produces organic food to be sold. They charge more, partially because it costs more to produce, but also because people are willing to pay more for organic foods, despite the lack of scientific support that it’s healthier or better.

Whatever your reasons, if you’ve got the money, go ahead buy some organic food if that makes you happy. It’s just not going to do much for you from a health perspective. The science of organic food just doesn’t support that opinion.

Editor’s note: A version of this article was originally published in December 2012. It has been substantially revised and updated to include more comprehensive information, to improve readability and to add current research.

Key citations

 

 

The Original Skeptical Raptor
Chief Executive Officer at SkepticalRaptor
Lifetime lover of science, especially biomedical research. Spent years in academics, business development, research, and traveling the world shilling for Big Pharma. I love sports, mostly college basketball and football, hockey, and baseball. I enjoy great food and intelligent conversation. And a delicious morning coffee!