The O word is on everything from spinach to ketchup -- should you bite?

Organic food sales have grown 15 percent or more every year over the past decade, which indicates many Americans are concerned about how their food is nurtured. And these days, the term "organic" is applied to many fitness foods such as pasta, chicken and milk. Heck, even Wal-Mart has jumped on the organic bandwagon.

But are these so-called "greener" foods worth their lofty prices? Let's find out.

The meaning of organic

Any food packaging that sports the USDA organic label was grown or made with ingredients grown with no pesticide and herbicide inputs -- chemicals that may have a detrimental impact on human health such as lowering immunity. In order to be labeled organic, at least 95 percent of the ingredients in the food have to have been organically produced. Livestock raised organically must be fed organic feed and can't be administered antibiotics or growth hormones. Genetically modified food is also not permitted under the organic umbrella.

The argument for organic

For some time, organic nay-sayers have claimed that there's little research proving that organic food is more nutritious. That is changing. There might not be much difference between organic and non-organic with respect to processed foods such as cereals and crackers. But organic fruits, vegetables and dairy do appear to contain more disease-fighting nutrients.
A four-year study conducted by United Kingdom's Newcastle University suggests that organic fruits and veggies contain extra iron, zinc, copper and a hefty 40 percent more antioxidants than their non-organic counterparts. Antioxidants can help ward off chronic diseases like cancer and heart disease and may improve muscle recovery after exercise.

The researchers also found that the organic dairy tested had a healthier fat profile making it more heart healthy. While, scientists from the University of California-Davis determined that tomatoes grown organically have more flavonoids which are antioxidants that protect against cancer. Vitamin C -- a powerful antioxidant in its own right that can boost immunity -- has also been found in more substantial amounts in organic fruits and vegetables.

Remember, when going organic, you may not be the only one benefiting. Organic agriculture keeps harmful chemicals out of the soil and waterways making it much more planet friendly. Farm workers and others involved in organic growing and production are also spared the ill effects of working with pesticides.

The argument against organic

Organic foods can cost twice as much as regular fare which is a problem if you are on a tight budget or have a family with many mouths to feed. The reason for the higher costs is that controlling pests and weeds without the use of man-made chemicals is more labor intensive and has added expenses. However, as organic becomes more popular, the price tags are dropping.
Some people assume that just because something is labeled organic it is healthier. Organic potato chips are still health pariahs and should be handled with caution.

Bottom Line

Turning over a new, greener leaf and going 100 percent organic may not be  economically and logistically practical for all. But if you choose organic versions of a few of the foods that you eat regularly, such as milk and apples, you can boost the percentage of your diet that is organic without completely emptying your wallet. The key is to be smart with your choices.
According to the Environmental Working Group, some produce has more pesticide residues than others. Peaches, apples, bell peppers, celery, nectarines, strawberries, cherries, lettuce, grapes, pears, spinach and potatoes are the dirty dozen and contain the most pesticide residues. So it might be wise to fill your cart with the organic versions of these if your budget allows.

Produce that is peeled such as avocado, kiwi and banana contain the least amount of pesticide residues. You can go to http://www.foodnews.org/pdf/EWG_pesticide.pdf for a full list of fruits and vegetables with the most and least pesticide residues.

While washing and rinsing produce may reduce levels of some pesticides, it does not eliminate them. Peeling also reduces exposure, but valuable nutrients such as fiber often go in the trash with the peel from produce such as carrots and apples.

Organic or not, you can improve your health and the health of the planet by choosing more foods that are grown and raised close to your home turf. The further food has to be transported, the more nutrients that are lost and the more fossil fuels that must be used in getting it onto your dinner plate. Farmers' markets are filled with healthy, homegrown fare that can keep you at the top of your game.

Matthew Kadey is a Canadian-based dietitian and nutrition writer (mattkadey.com)