The new paper did find just that, though the benefit may be meaningless. Antioxidants and flavonoids have yet to show any measurable health benefit, but the demographic that buys organic food is more likely to buy those kinds of supplements touting benefits of phytochemicals.
The organic proponents in this new paper claim that the contradictory and conflicting results from previous research on organic and conventional crops’ phytochemical content could be a function of short study periods and the exclusion of variables such as weather - and think they have done a better job. They undertook a study from 2009 to 2014 of organic process (the European Commission definition) and conventional “Red Baron” and “Hyskin” onions, which have flavonoids such as quercetin.
Modern health fads suggest that these flavonoids and others are beneficial for people with a range of health conditions.
Teagasc Research Officer, Dr. Dilip Rai, Teagasc Food Research Centre Ashtown, explains, “Over the six-year study, measurements confirmed that weather could be a factor in flavonoid content, regardless of whether they were grown under organic conditions or not. For example, the levels of flavonols decreased in Red Baron onions from 2010, the year with the lowest temperatures, but increased in 2011 and 2014 when temperatures were higher and rainfall was down. The researchers also found that antioxidant activity was higher in both varieties of organic onions. And the flavonols in organic onions were up to 20 percent higher than in conventional ones.”
Citation: Feiyue Ren, Kim Reilly, Joseph P. Kerry, Michael Gaffney, Mohammad Hossain and Dilip K. Rai, “Higher Antioxidant Activity, Total Flavonols and Specific Quercetin Glucosides in Two Different Onion (Allium cepa L.) Varieties Grown under Organic Production Results from a Six-Year Field Study”, Journal of Agricultural and Food Chemistry, http://pubs.acs.org/doi/pdf/10.1021/acs.jafc.7b01352