By identifying the genes involved in creating the compounds, researchers believe they are a step closer to breeding super vegetables such as kale and cabbage with mega-doses. Dr Juvik, whose work is published in the journal Molecular Breeding, said: 'It's going to take a while.
"This work is a step in that direction, but is not the final answer.
"We plan to take the candidate genes we identified here and use them in a breeding programme to improve the health benefits of these vegetables. Meanwhile, we'll have to make sure yield, appearance, and taste are maintained as well."
Phenolic compounds are flavourless and stable, meaning the vegetables can be cooked without losing any health benefits. Once consumed, the compounds are absorbed into the body and either sent to certain areas or concentrated in the liver.
Flavonoids spread through the bloodstream and reduce inflammation through antioxidant activity. Humans cannot produce their own phenolic compounds.
Dr Juvik said: "These are things we can't make ourselves, so we have to get them from our diets.
"The compounds don't stick around forever, so we need to eat broccoli or some other Brassica vegetable every three or four days to lower the risk of cancers and other degenerative diseases."