Organic tomatoes healthier: study

Xinhua News Agency


LONDON, Jul 5, 2007 (Xinhua via COMTEX) -- A 10-year study comparing organic tomatoes with those grown conventionally suggests that organic food is healthier for people.

New research published in the latest issue of New Scientist available Thursday found levels of the flavonoids quercetin and kaempferol were found to be on average 79 and 97 percent higher, respectively, in organic tomatoes. Flavonoids have been linked to reduced rates of cardiovascular disease, some forms of cancer and dementia.

Differences in soil quality, irrigation practices and the handling of harvested produce have made direct comparisons difficult in the past. So in this study, researchers at the University of California, Davis, used data from a long-term project in which standardized farming techniques are used to reveal trends in crop productivity.

The researchers say the finding can be explained by the availability of nitrogen. Flavonoids are produced as a defense mechanism that can be triggered by nutrient deficiency. The inorganic nitrogen in conventional fertilizer is easily available to plants and so, the researchers suggest, the lower levels of flavonoids are probably caused by over-fertilization.

Previous research has found no differences between organic and conventional crops such as wheat or carrots.