The debate about organic food is in the news again today as a long-term Californian study suggests that organically grown tomatoes contain more of two types of flavonoids, quercetin and kaempferol. The leader of the research, Alyson Mitchell, suggests that this is because non-organic tomatoes are grown with fertiliser that makes nitrogen easily available to the plants. Flavonoids are produced by the plants as a defence mechanism against nutrient deficiency so, she concludes, less are generated when tomatoes are grown in this nitrogen rich soil.
Flavonoids are antioxidants. It has been proposed that they are one of the components present in fruit and vegetables that may be responsible for the relatively low rate of cardiovascular disease that has been associated with high levels of fruit and vegetable consumption. There is, however, not enough evidence to show that increasing intakes of flavonoid rich foods will reduce heart disease, because other factors associated with high fruit and vegetable intakes may be responsible for their cardiovascular protection.