Eating broccoli twice a week could lower the risk of cancer, type-two diabetes and heart disease, scientists suggest.
Antioxidants such as phenols and flavonoids found in the vegetable are thought to help the body fight off disease.
Scientists believe eating broccoli - or other vegetables from the Brassica group - every three to four days gives enough of these compounds to improve the immune system by stopping inflammation.
Researchers at the University of Illinois in the US are trying to breed vegetables with mega-doses of the antioxidants, in the hope of creating a true "superfood".
Geneticist Dr Jack Juvik, who is leading the project, said: "We need inflammation because it's a response to disease or damage, but it's also associated with initiation of a number of degenerative diseases. People whose diets consist of a certain level of these compounds will have a lesser risk of contracting these diseases."
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."