Stress on our food plants may be hard for the plants, but good for us. Scientists are now studying the biochemical effects of agricultural practices in great detail, and one consistent finding is that plant stress--from insects, heat, sunlight, water and mineral deficiencies--can induce plants to produce higher levels of antioxidants and other phytochemicals that may be good for human health. Organic agriculture, with no pesticides or mineral concentrates, usually exposes crops to more stress, and its produce is usually higher in phytochemicals. Now, in a study of syrah grapes grown near Chateauneuf du Pape in southern France, French scientists have found higher levels of antioxidant anthocyanin pigments in the conventionally grown crop. They attribute this to the possibility that, because the grapevines were already severely stressed by heat and drought, the spraying of pesticides constituted an additional, chemical stress. If this theory is correct, then pesticides may sometimes contribute more to human nutrition than just higher crop yields and less expensive produce.
Vian M.A. et al., J. Agric. Food Chem. 2006 54 (15) 5230