Flavonoid rich organic food better for you
Published July 6th, 2007
Organic fruit and vegetables may be better for you than conventionally grown crops, US research suggests
Researchers report that in a ten-year study comparing organic tomatoes with standard produce, it has been found that organic tomatoes contained almost double the level of flavonoids, a type of antioxidant.
Writing in the Journal of Agricultural and Food Chemistry, the team said nitrogen in the soil may be the key.
Dr Alyson Mitchell, a food chemist at the University of California, and colleagues measured the amount of two flavonoids - quercetin and kaempferol - in dried tomato samples that had been collected as part of a long-term study on agricultural methods.
They found that on average they were 79% and 97% higher respectively in the organic tomatoes than in the conventionally grown fruit.
New Scientist magazine reported that the different levels of flavonoids in tomatoes are probably due to the absence of fertilisers in organic farming.
Flavonoids are produced as a defence mechanism that can be triggered by nutrient deficiency, such as a lack of nitrogen in the soil.
The inorganic nitrogen in conventional fertiliser is easily available to plants and so, the researchers suggests, the lower levels of flavonoids are probably caused by over-fertilisation.
The Food Standards Agency says there is some evidence that flavonoids can help to reduce the risk of cardiovascular disease and they are currently carrying out a study to look at the health benefits in more detail.
“These findings also confirm recent European research, which showed that organic tomatoes, peaches and apples all have higher nutritional quality than non-organic.”
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