Antioxidants in organic tomatoes are healthier for heart & blood pressure, revealed in a 10-year US research study comparing organic tomatoes with those grown conventionally.
Antioxidants have been linked to reduced rates of cardiovascular disease, some forms of cancer and dementia.
The study published in the Journal of Agricultural and Food Chemistry.
Alyson Mitchell, a food chemist who led the research at the University of California, Davis, revealed that the levels of the flavonoids quercetin and kaempferol were found to be on average 79 and 97 per cent higher, respectively, in organic tomatoes. Researchers measured the amount of the antioxidant (flavonoids) in dried tomato samples of both organic and non-organic varieties as part of a long-term study on agricultural methods.
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.
New Scientist magazine also reported that the different levels of flavonoids in tomatoes are probably due to the absence of fertilisers in organic farming.
The US Food Standards Agency (FSA) says there is some evidence that flavonoids can help reduce the risk of cardiovascular disease but they are currently carrying out a study to look at the health benefits in detail.