Organic tomatoes a better health option

Jul 8 2007

According to a new study organic food may be a better health option after all.

A 10-year study comparing organic tomatoes with those grown conventionally suggests that organic tomatoes have more antioxidants.

The researchers from the University of California say the levels of the flavonoids quercetin and kaempferol were found to be on average 79 and 97 per cent higher in organic tomatoes.

Alyson Mitchell, a food chemist who led the research, says these flavonoids are known antioxidants and have been linked to lower hypertension (high blood pressure), thus lowering heart disease and stroke risk and some forms of cancer and dementia.

Mitchell says in previous studies between organic and conventional crops such as wheat or carrots, differences in soil quality, irrigation practices and the handling of harvested produce have made direct comparisons difficult.

Mitchell's team used data from a long-term project in which standardised farming techniques are used to reveal trends in crop productivity.

The researchers believe that it is the quality of the soil that gives the organic tomatoes their higher flavonoid levels, specifically, the absence of fertilizers.

It appears that when nitrogen levels are not high enough in the soil, plants themselves produce flavanoids as a defence mechanism and when inorganic nitrogen, which is present in everyday fertilizers is used, over-fertilization takes place, which may hamper the production of flavonoids.

The findings support recent European research, which showed that organic tomatoes, peaches and processed apples have higher nutritional quality than non-organic.

But not all experts are convinced and say this latest study does not prove that a healthy diet must be organic.

Some believe the evidence of the health benefits for flavonoids is conflicting, and say higher flavonoid levels may not necessarily make organic food healthier and depends on the relevance of the differences to the human body.