The study suggested that the pesticides and herbicides used by conventional growers hampers the plants’ production of phenolics, chemicals that naturally defend the plants and are beneficial to human health. Fertilizers, on the other hand, appear to increase levels of anti-cancer compounds in the plants.

Plants produce flavonoids--phenolic compounds that have potent antioxidant activity--in response to environmental stressors, such as insects or competing plants. Plants that have been exposed to herbicides and pesticides have less of a need to produce such compounds, and therefore produce fewer antioxidants than organically grown food.

The study compared the total antioxidants found in corn, strawberries and marionberries (a type of blackberry) that had either been grown organically (no herbicides, pesticides or fertilizers used), sustainably (fertilizers but no herbicides or pesticides were used) and conventionally (synthetic chemicals were used).

Organic and sustainably grown foods were found to have significantly higher amounts of antioxidants than conventionally grown food. Specifically, levels of antioxidants in sustainably grown corn were 58.5 percent higher than conventionally grown corn, while organically and sustainably grown marionberries had about 50 percent more antioxidants than conventionally grown berries. Further, sustainably and organically grown strawberries had about 19 percent more antioxidants than conventionally grown strawberries.

Sustainably grown produce had the highest antioxidant levels overall, indicating that a combination of organic and conventional growing methods may be most beneficial.

The higher level of antioxidants in the organically grown food is enough to have a significant impact on health and nutrition, researchers noted.

Organic foods are important not only for what they give you--more antioxidants and nutrients--but also for what they don’t give you. If you eat organic vegetables, you will not be exposed to the chemicals and pesticides that are used with conventionally grown food.

Unfortunately, organic foods can be hard to find, especially for those living in rural areas, and are more expensive than non-organic foods.

If you don’t have access to organic vegetables, please realize that non-organic vegetables are better than no vegetables at all. The benefits of the vegetables, particularly if they are consumed raw, outweigh the risks of pesticide residues.

Dr Joseph Mercola