Eat the rainbow. You’ve heard this advice before, and it seems sound. After all, fruits and vegetables are packed with vitamins, minerals, and belly-filling fiber. But they’re also loaded with good stuff you may not have heard of: phytonutrients.

Phytonutrients have many aliases: phytochemicals, polyphenols, antioxidants. They’re natural chemicals produced by plants to help protect them from threats like bugs, fungi, parasites, and even the sun. When you eat these plants, similar protections are passed to you.

You’ve surely heard of a few of these powerhouses, but there are actually thousands of them. Vanessa Millovich, RDN, a dietitian at Kate Farms, answers some common questions about how phytonutrients can do your body good.

Question #1: What are the key health benefits of phytonutrients?

Every fruit and vegetable contains multiple phytonutrients, which combine to offer a variety of health benefits. Here’s a guide to some common phytonutrient groups.

Carotenoids: Most often found in yellow, orange, and red foods, carotenoids include names you know: beta-carotene, luetin, and lycopene. In some cases, the body converts them to vitamin A, which is important for healthy vision. Carotenoids can also boost the immune system and reduce inflammation, which is root cause of many chronic conditions.

Ellagic acid: This phytonutrient is thought to protect against cancer by slowing the growth of tumor cells. Pomegranates, strawberries, and raspberries all have high concentrations.

Glucosinolates: They’re found in cruciferous vegetables like brussels sprouts and cabbage and may protect against certain cancers.

Phytoestrogens: These phytonutrients—found in soy, sesame seeds, and flaxseeds—mimic the effect of estrogen, making them especially good for women. Studies suggest they protect against endometrial cancer and bone loss.

Polyphenols: This large class includes everyone’s two favorite phytonutrients: resveratrol, found in grapes and red wine; and caffeine, found in coffee. Both have been linked to improved cardiovascular health.

Saponins: Beans, peas, soybeans, herbs, and quinoa have high concentrations of saponins, which may help lower cholesterol, strengthen your immune system, and reduce cancer risk.

Question #2: How do phytonutrients work?

Most act as antioxidants in the body, attaching themselves to free radicals and essentially deactivating them. Free radicals are single oxygen atoms that, left unchecked, damage healthy cells and cause inflammation.

Question #3: How do I get phytonutrients?

You can take supplements—quercetin and beta-carotene are two common ones—but you can get all the phytonutrients you need from food. Specifically, colorful foods. Here are some great sources:

• Red: tomatoes, peppers, strawberries, watermelon, grapes, apples

• Orange: carrots, peppers, squash, oranges, apricots, cantaloupe

• Yellow: peppers, corn, bananas, pineapple

• Green: spinach, kale, cabbage, avocados, asparagus

• Blue and purple: blueberries, blackberries, eggplants, raisins, grapes, plums

Question #4: Is it just about color?

Color is a great guide. In general, the brighter or deeper the color, the more phytonutrients a fruit or vegetable contains. That said, color isn’t everything.

Remember: Phytonutrients are natural pesticides. As a result, they have a naturally bitter, acrid, or astringent flavor. So, as with color, the stronger the flavor, the higher concentration of phytonutrients. For example, flavonoids, a type of polyphenol, add bitterness to garlic and onions.

Question #5: Are phytonutrients critical to good health?

Phytonutrients are not essential, and even though they sound similar, they’re not vitamins and minerals or substitutes for them. But eating plant-based foods every day can help prevent disease and keep your body functioning optimally. 

In fact, a meta-analysis found that eating fruits and vegetables is associated with a reduced risk of cardiovascular disease, cancer, and all-cause mortality. 

Question #6: How do I know I’m getting enough—and the right ones?

You don’t have to focus on a single phytonutrient or micromanage your intake. Instead, put plenty of color on your plate. As a general guideline, you want to eat five servings of fruits and vegetables a day, and the frozen kinds work just as well. 

Along with disease prevention, fruits and vegetables contain plenty of fiber, which will fill you up, help control your appetite, and can help reduce your calorie intake—all great benefits.