Abstract from paper

Flavonoids, plant-derived polyphenolic compounds, have been linked with health benefits. However, evidence from observational studies is incomplete; studies on cancer mortality are scarce and moderating effects of lifestyle risk factors for early mortality are unknown. In this prospective cohort study including 56,048 participants of the Danish Diet, Cancer, and Health cohort crosslinked with Danish nationwide registries and followed for 23 years, there are 14,083 deaths. A moderate habitual intake of flavonoids is inversely associated with all-cause, cardiovascular- and cancer-related mortality. This strong association plateaus at intakes of approximately 500 mg/day. Furthermore, the inverse associations between total flavonoid intake and mortality outcomes are stronger and more linear in smokers than in non-smokers, as well as in heavy (>20 g/d) vs. low-moderate (<20 g/d) alcohol consumers. These findings highlight the potential to reduce mortality through recommendations to increase intakes of flavonoid-rich foods, particularly in smokers and high alcohol consumers.

great paper--protective effects from flavonoids: oranges tomatoes grapefruit cherries: anti-inflammatory,anti-carcinogenic

celery parsley for bladder ovarian cancers and glioma

Green Tea

grapes berries peanuts balsamic sage for prostate breast cancers

berries for cardiovascular disorders

Fisetin(in strawberries peaches onions grapes kiwi cucumber tomatoes) flavonoid for myeloma and melanoma

kiwifruit

Quercitin apples onions garlic--article is contradictory here--can cause DNA damage but also says protective against cancer in low doses but opposite effect in high does--helps colon cancer

Not advisable to take flavonoids in supplement form

You're asking about a really wide range of compounds, some of which are beneficial and some of which can be toxic. There's not going to be a good single source.

Can you be more specific about what you're looking for?

Yum...flavonoids. I love cocoa, and now I've got a great reason to drink it even more often.

Yum to dark chocolate, too.