“I love adding it onto a salad or mixing it on any kind of dish,” Singh says. It’s a member of the bitter greens family, he continues, “and bitters are also good with digestion and bloating.” Plus, they’re rich in calcium, potassium, folate, and a host of other vitamins and minerals; arugula is also a cruciferous vegetable, which means it’s packed with fiber and prebiotic material to sustain gut health. 

“It gives a little spice to your food, a little flare to it,” Singh continues. “People say, ‘Oh, my salad is monotonous,’ well, do something different. Put some cilantro in there, put some arugula in there, and all of a sudden you’re eating something different, even though it’s really still a salad.” 

What Mayer calls your “own personal testing mechanism.” Translation? A simple taste test. 

Take a bite into any polyphenol-rich berry (blueberries, blackberries, strawberries, what have you), and really savor it. Reflect on the first explosion of flavor, the aftertaste, and how concentrated it seems. If it tastes rich and sweet, it’s likely brimming with polyphenols; if it’s bland, perhaps less so.

The thing is, polyphenols are produced in the plant’s root system—meaning, when the soil is stripped of its microbial life and pumped with pesticides, the plant’s nutrient content suffers. Functional medicine doctor Mark Hyman, M.D., agrees, as he once told us that broccoli was twice as nutritious 50 years ago when the soil was brimming with diverse microbial life. And it’s those nutrient-dense fruits and veggies that actually provide the most intense, mouthwatering flavor.

That’s why, Mayer explains, if the berries don’t taste like, well, berries, “they probably have a low concentration of polyphenols.” Take strawberries, for example: Have you ever eaten a tiny—yet intense!—organic strawberry and remember the rush of flavor? “Compare them to the big strawberries you find in the supermarket, and they have essentially no taste,” Mayer says. “If you didn’t see it, you wouldn’t know it’s a strawberry.” 

See, plants produce polyphenols when they’re injured or under stress, Mayer explains on this episode of the mindbodygreen podcast—like exposure to pests, drought, or UV light. Those stress signals shimmy down into the plant’s root system, which excretes a sugar-like molecule that attracts microbes into the roots. “These microbes then stimulate the plant roots to produce polyphenols, which is the medicine of the plant,” he continues. 

Here comes the fun part: When you eat those stressed out, polyphenol-rich plants, these unique phytonutrients and other plant compounds (e.g., fiber) interact with our gut microbes to help produce good-for-you molecules.* “We ingest [the plants], and then our own microbes break [them] down. It’s almost like a sealed package,” says Mayer. “They break it down once it gets down to the large intestine and open up the package with all the goodies that are in there.”*

Still with us? Below, find Mayer’s menu of polyphenol-rich foods.