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
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.