There was article today in the New York Times with a study casting doubt on the advantages or Organic Meat and Produce. http://www.nytimes.com/2012/09/04/science/earth/study-questions-advantages-of-organic-meat-and-produce.html?_r=1
Their conclusions said “the fruits & vegetables were on average, no more nutritious than their conventional conterparts” They also concluded “conventional fruits and vegetabls did have more peticide reside, but the leveles wer almost always under the allowed safety limits” “The Envoirnmental Protection Agency sets the limits a levels that do not harm humans.”
I say their study did not cover the effects of the pesticides we find in our body and even in the bodies of our newborn babies. They simply did not carry the study far enough. Pesticides found in our food cause our liver to work really hard . As a result or liver does not have the energy to produce the necessary bile acids that allow for the vital digestion and absorption of the fat, oils and fat souluable vitamins from the foods you eat among other functsion. All of these activities keep us healthy and young.
My conclusion is to follow the EWG list of the Dirty Dozen and the Clean 15
http://www.ewg.org/foodnews/summary/
As regards to fish I like to follow the guidelines put out by the Marine Stewardship Council which certifies seafood that is caught or raised in a sustainable, environmentally friendly manner. Items that meet its criteria are marked with a MSC-certified label. They also tell you which fish have the most amout of mercury and other toxins in them. You can read the full article on healthy fish 
https://eatwellenjoylife.com/seafood-sustainability/
Finally regarding animals we eat, the article says”organic meant contained considerably lower levels of antibiotic-resistant bacterian than conventionally raised animals did, but bacteria, antibiotic resistant or otherwise would be killed during cooking.” Personally I never eat meat or chicken that is convetionally raised becuase I don’t want the antibiotics in my system, nor I want to support the inhumane treatment of those animals. Have you ever seen a factory farm? It is so disgusting and shows no regard for other living things. Not something I advocate.
I hope this information helps you make the best healthy choices for yourself.
