Fresh fruit and vegetables that are not treated with pest-fighting chemicals may contain up to 60 percent more cancer-fighting phytochemicals, a recent study indicates.

After studying the effect on three different types of produce, the researchers found that food grown without pesticides and herbicides contained between 19 and 60 percent more flavonoids, a particular kind of phytochemical with certain cancer-fighting properties. These foods were compared to food produced in the conventional way.

The findings were published in a recent issue of the American Journal of Agricultural and Food Chemistry.

An added benefit

The researchers believe that this study might point to the anti-cancer benefits of organic produce. This could be an added benefit of buying organic food.

Flavonoids are antioxidants, which can be found in a wide variety of fruit, vegetables, tea and wine. Oxidation is associated with an increased risk of heart disease, stroke and several other diseases.

More research is, however, needed to determine whether flavonoid content stays elevated when food is transported from the field to the supermarket.

Methodology and results

During the study, the researchers compared flavonoid content in strawberries, corn and marionberries (a type of blackberry found in the US). Three different types of samples were compared: samples produced without the use of pesticides, herbicides or fertiliser; samples produced with fertiliser only; and samples produced by using all three of these chemicals (the conventional method).

The researchers found that the flavonoid levels were 59 percent higher in corn that have been produced with fertiliser only in comparison to corn raised with pesticides and herbicides as well. Marionberries and strawberries grown with or without fertilisers respectively had approximately 50 percent and 19 percent more flavonoids than berries grown in the conventional way.

The researchers believe they would find similar results in other types of fruit and vegetables.

Foods contain different amounts of flavonoid

Plants contain flavonoids to protect themselves from outside stresses, like pests and ultraviolet radiation. When pesticides are used, natural flavonoid levels are lowered.

The shortcomings of the study may be that the researchers didn't measure the different types of flavonoids present in the selected crops. Not all flavonoids are equally beneficial in humans and some might even be harmful, he said.