Nutritional Differences Among Organic vs. Conventionally Grown Foods

I have started a research project to determine if there is enough scientific evidence supporting the idea that eating organic foods has more nutritional value than conventionally grown foods.  There are many claims that this is the case, and while I do not believe there is enough evidence to support this idea, I owe it to my readers to investigate.  Aside from health, there are other reasons one may have for buying organically grown foods including political, social, moral, and environmental reasons.  (Though all of these are debatable, as well.  For instance many argue that locally-grown, conventional foods are healthier than organic foods that are shipped from across the country.  And, conventional farming uses less land than organic. I'll save those debates for another day). 

Personally, I try to buy organic foods for the purpose of avoiding additional chemicals.  I like to buy meats, eggs and produce knowing that they have the least amount of pesticides, growth hormones, or any other added chemical that is not naturally-occurring in the food.  On the other-hand, I will agree that it is better to buy locally because many local farmers do, in fact, follow organic farming methods but they are too small to afford the high price of getting certified organic. (Again, another blog topic for another day).

Aside from chemicals, there are many people who believe that organic foods have a higher nutrient content than conventionally grown foods.  I have spent hours today searching through the library databases trying to find out how many studies have confirmed nutritional differences between the two farming methods and I am coming up empty.  I will continue to research this topic and will keep looking for new studies that may show differences.  But for now, I am not seeing enough scientific data backing up the idea that organic foods are more nutritious than conventional. 

Here is one abstract I found in PubMed:

Bourn D, Prescott J. A comparison of the nutritional value, sensory qualities, and food safety of organically and conventionally produced foods. Crit Rev Food Sci Nutr 2002;42(1):1-34

Given the significant increase in consumer interest in organic food products, there is a need to determine to what extent there is a scientific basis for claims made for organic produce. Studies comparing foods derived from organic and conventional growing systems were assessed for three key areas: nutritional value, sensory quality, and food safety. It is evident from this assessment that there are few well-controlled studies that are capable of making a valid comparison. With the possible exception of nitrate content, there is no strong evidence that organic and conventional foods differ in concentrations of various nutrients. Considerations of the impact of organic growing systems on nutrient bioavailability and nonnutrient components have received little attention and are important directions for future research. While there are reports indicating that organic and conventional fruits and vegetables may differ on a variety of sensory qualities, the findings are inconsistent. In future studies, the possibility that typical organic distribution or harvesting systems may deliver products differing in freshness or maturity should be evaluated. There is no evidence that organic foods may be more susceptible to microbiological contamination than conventional foods. While it is likely that organically grown foods are lower in pesticide residues, there has been very little documentation of residue levels.

You can find this abstract and more information by searching http://www.ncbi.nlm.nih.gov/pubmed/

My plan is to blog about my findings as I continue to research this topic.  If you haven't already, subscribe to my RSS feed and you will receive updates on my research project.

Comments

[Trish]

Here are a couple of more studies Kim and recent ones too.

1) Researchers studying cultivation practices for high-bush blueberries in New Jersey found that blueberry fruit grown organically yielded significantly higher fructose and glucose levels, malic acid, total phenolics, total anthocyanins and antioxidant activity than fruit grown using conventional methods.
Journal of Agricultural and Food Chemistry, Vol. 56, pages 5,788-5794 (2008), published online on July 1, 2008.

2) A report jointly produced by The Organic Center and professors from the University of Florida Department of Horticulture and Washington State University provides evidence that organic foods contain, on average, 25 percent higher concentration of 11 nutrients than their conventional counterparts.,
www.organic-center.org/reportfiles/5367_Nutrient_Content_SSR_FINAL_V2.pdf.
March 2008

More studies cited here
http://www.ota.com/organic/benefits/nutrition.html

LOCAL OR ORGANIC?
I agree the label 'organic' can sometimes just be window dressing. And local is often organic or mostly so without having the label.
It comes down to know your farmer. Ask around at your farmers market, co-op or local market. People who are knowledgeable about their practices will inform you. An example is Chicoine Family Farm (Easthampton) you can buy their beef at several local farmers market (evening Springfield). They do not have an organic certification, but they grass-feed their cattle, don’t use hormones or antibiotics and take every measure they can to ensure the herd’s safety and wellness. Good people, good food and a healthy buy.
If a local farmer practices organic techniques but doesn’t have the organic paper I’d definitely choose them over one that’s been trucked in but has the label.

[Kimberly Bither]

Thanks Trish.

I agree local is good, if it is available. And we agree, it is typically "organic", anyway, with or without the label. And to add to that many labels that state organic aren't necessarily great. As the demand for organic foods grows, the farming practices become closer to conventional. In their defense, they have to in order to meet demand. The reality is that if you have the means to buy organic, and choose to, that is fine, but it could not sustain our entire 300 million population.

Like anything, there is never one rule, but usually loose guidelines (at least in my opinion). For example, you are right it is good to know the local farm practices and most likely your food will be fresher. (Thanks for the tip on the farm in Easthampton, I was not aware of them and will look for them, as I too, prefer local meat.) However, I can't imagine not having any fruits and vegetables all winter long, so then it is necessary to have them shipped in. I guess what I am saying is that it is OK to buy local and shipped, depending on the circumstance. As for meat, I do try to avoid the "big-name" companies and buy local or organic meats, when possible.

Thanks for sharing the additional studies. I still think in order to really prove any nutritional superiority, we are going to need a lot of studies. As for the OTA website, I try to shy away from those as their information will be biased, which is why I always try to get my info from government or universities as it should be less biased.

My biggest concern when writing and addressing the topic of organics vs. conventional is cost to society. I feel that the media, as well as people, are trying to make everyone think they have to buy organic. However, this is just not affordable for many struggling Americans families and I don't want them to think if they buy conventional, because it is what they can afford, that they are not getting nutritious foods. As they still are getting nutritious foods.

Thanks, Trish, for sharing and I hope to be writing a lot about this topic in the coming months.

Keep the comments coming!

[VicinSea]

One of the things to look for: the USDA required nutritional labeling information used by food processors hasn't been updated since the 1940's, even though the information available through the USDA has been updated many times-manufacturers still use the old info because it is consistently more attractive than the current info. I wrote about this a while ago and have some links in the story that might help your research.

http://vicinsea.blogspot.com/2008/03/new-reason-to-grow-your-own-veggies.html

[Trish]

Thanks Kim. All good points and counter-points.

WINTER FRUITS & VEGGIES
“I can't imagine not having any fruits and vegetables all winter long” ME TOO! I completely agree with you there. There's no need to become a 'localvore'. I think it's more a matter of discovering what else is possible (Winter greens, squashes etc.)

STUDY BIAS?
I understand your concern. I’m sure that’s why OTA teamed up with several universities (U of FL, WSU) and had Dr. Andre Weil (University of Arizona) write the forward.

Another point to consider. You may have noticed that the OTA/multi-University study is not just a new study adding to the noise but rather a meta-analysis of 97 previously published studies.

It also highlights the lack of focus on phytonutrients, the dynamic nutrient group recently in the spotlight and known for their positive impact on CRP levels amongst many other markers.
They also point out that a large-scale, multi food comparison would cost huge bucks. What unbiased agency or organization would pay for such a study?

Even supposedly neutral organizations such as the ADA have been questioned by the conscientious press for selling corporate sponsorships to Kraft. Ensure, Monsanto and Equal. .
http://blog.kimberlyfitness.com/the_wellness_workout/2006/12/conflict_of_int.html

CAN ORGANIC FEED THE WORLD?
If we cast aside the window dressing of “organic” and focus instead on organic farming as a part of a whole range of sustainable policies and practices I think a different conclusion is possible.

An entomologist from University of California, Berkeley has a fascinating paper here that addresses world hunger dilemma with regard to the organic farming vs conventional farming question.

“Our current world food production is more than sufficient to provide an adequate diet to all humans, yet more than 840 million people are suffering from hunger. Hunger is a problem of poverty, distribution, and access to food. The question then, is not "how to feed the world", but rather, how can we develop sustainable farming methods that have the potential to help the world feed and sustain itself.”
http://www.cnr.berkeley.edu/~christos/articles/cv_organic_farming.html

Here a director of one of the worlds biggest biotechnology companies concurs with him - that world hunger is more of an economical/political problem than a farming one.
http://www.psrast.org/orgfarmmonbiot.htm

In a nutshell it comes down to the fact that organic farming empowers citizenry to produce their own food rather than be merely customers of a global food production industry.

“Give a man a fish(or food) feed him for a day. Teach a main to fish (or farm) and feed him for life.”

[Colin Shaw]

There is also research in the UK and Denmark about organic milk. Details of the findings can be found at: http://news.bbc.co.uk/1/hi/health/4153951.stm

The research found that: "organically produced milk which was, on average, 50% higher in Vitamin E than conventionally produced milk.

Organic milk was also 75% higher in beta carotene, which is converted into Vitamin A in the body."

Col - www.organicgarden.org.uk