In the past week, many news media outlets reported on research by UC Davis food chemist Alyson Mitchell that was published in the June 23 issue of the Journal of Agricultural and Food Chemistry. For example, on July 5, the BBC News titled its story "Organic tomatoes 'better' for heart." The story was picked up in Australia, India, Africa and many American publications.
Mitchell and her colleagues studied dried tomatoes that had been collected over 10 years for an unrelated research project that compared organic, conventional and intermediate growing methods. They found statistically higher levels of quercetin and kaempferol aglycones in organic tomatoes, according to the journal article. The substances are flavonoids believed partly responsible for lower rates of cardiovascular disease and some cancers in people who eat lots of fruits and vegetables. Mitchell received a $34,000 ANR Core Issues Grant in 2004 to conduct her research.
According to the Sacramento Bee article, published July 4, the research adds to a conflicting body of knowledge about whether organic foods provide significant nutritional benefits.
"There's a lot of confusion," Mitchell is quoted in the Bee. "For every study that shows there's a difference, there's another that shows there isn't."
Bee writer Carrie Peyton Dahlberg reported that Mitchell said the higher levels of flavoniods in the organically grown tomatoes may be due to an increase in organic matter and overall soil fertility due to organic production methods.
"That meant growers didn't need to use as much compost to keep nitrogen levels high. And without that extra boost of growth-promoting nitrogen, plants seemed to devote more energy to producing flavonoids," Dahlberg wrote.
However, the article notes that Mitchell said that the research findings don't necessarily mean that all organic tomatoes would contain more flavonoids.
