When Apple held its initial public offering (IPO) in 1980, a share cost $22. As of this writing, a share sells for $206.50.

It was a good buy early on, but who could have imagined its future increase in value from that first day?

You could say the same is true for apples of the Fiji, Gala, and Delicious varieties.

Of course, everyone has heard that an apple a day keeps the doctor away. But who knew that its nutrients — especially the flavonoids — would keep heart disease and cancer away too?

New research published in Nature Communications affirms the importance of eating a diet high in polyphenol flavonoids. And apples deliver many kinds — including quercetin, catechin, and procyanidins.

These compounds fight chronic inflammation and all the trouble it can cause.

Especially powerful are apple peels that are darker, redder, and bluer. (Macoun apples have shades of blue).

Other foods high in flavonoids include tomatoes, tea (green, in particular), and dark chocolate (75% cacao), as well as berries, citrus fruit, and leafy greens.

According to the study, which was based on data from more than 50,000 adults, people who consume 500 mg of flavonoids daily (enjoy seven to nine servings of fruits and veggies every day, along with green tea) have the lowest risk of death from heart disease and cancer.

The phytonutrient is especially beneficial to smokers, drinkers, and those with obesity or sedentary habits.

Of course, eating flavonoid-rich foods won't erase all the risks from an unhealthy lifestyle, but it's a great investment in your future.