We’re told that we should eat the rainbow, choosing a diet filled with a colorful variety of fruits and vegetables. These nutrient-dense foods contain a range of vitamins, minerals, and phytochemicals. But while we understand that phytochemicals keep us healthy, we might not understand why. 

Phytochemicals, also called phytonutrients, are substances found in fruits, vegetables, and grains that are part of a plant’s immune system, meant to keep it healthy and free of disease. And by keeping the plants healthy, they also serve to keep the person eating them healthy.

“Phytochemicals, which are found in the colorful parts of fruits and vegetables, are basically a plant’s defense system to protect them from oxidative damage. They also play that role in humans,” says Rachel E. Scherr, a dietitian and lecturer at San Francisco State University.

The reason it’s important to eat the rainbow is because each color of fruit and vegetable contains a different variety of phytochemicals, and to consume a wide variety of disease-fighting compounds, you need to eat a variety of plants. 

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Different Types of Phytochemicals

There are hundreds of types of phytochemicals, each found in different foods that do different things for the body. For example, carotenoids are the phytochemicals found in yellow and orange fruits and vegetables. Beta-carotene and lycopene are examples of carotenoids, of which beta-carotene is the most abundant in our diets.

“They’re neat because carotenoids are actually stored in our skin, which means we can easily measure them to see how much we’re consuming in our diet,” says Scherr.

What are Carotenoids?

Carotenoids function like antioxidants, meaning that these guys are really good at hunting down free radicals and pairing off with them so that they aren’t free to do damage to our cells.

According to an article in the journal Nutrients, carotenoids are known to be “potent scavengers of other reactive oxygen species.” Carotenoids are specifically focused on fighting free radicals that can cause cardiovascular diseases, cancer, and eye diseases. 

How do Polyphenols Help the Body?

Polyphenols, which are found in berries, chocolate, wine, and coffee, have both antioxidant and anti-inflammatory benefits for the body. Like carotenoids, polyphenols can suppress the action of free radicals by directly scavenging them and donating an electron to that free radical, which makes them less reactive in the body and keeps them from causing damage.

They’re known to keep arteries flowing, improve digestion and brain function, reduce blood sugar levels, and fight against cardiovascular disease and certain types of cancers. 

Isoflavones and Anthocyanins

Isoflavones, sometimes called phytoestrogens, are found in soy, lentils, and legumes. These naturally occurring estrogens are effective for improving cardiovascular disease but also reducing the impact that many women may experience during menopause. They have a chemical structure that’s similar to estrogen, so they can bind to estrogen via receptors in the body.

Anthocyanins are the phytochemicals that give purple and blue fruits and vegetables their pigment. They’re a type of flavonoid that also functions like an antioxidant to protect against DNA cleavage, the breaking of the covalent bonds that make up the backbone of DNA. They also improve immunity by boosting the production of cytokines and strengthening cell membranes. 

They’re known to improve cardiovascular, metabolic, and cognitive health as well as exercise performance and the risk of certain types of cancer.

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How a Plant-Based Diet Boosts Your Defense System

So, if you’re wondering why a plant-based diet is so important and why it has so many benefits for your health, phytochemicals are a big reason why.

The more often you consume a plant-based diet and all the fruits and vegetables that go along with it, the more likely you are to consume phytochemicals, the body’s very own defense system against aging. 

Read More: Microgreens Pack a Macro Nutritional Punch

Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

Sara Novak is a science journalist based in South Carolina. In addition to writing for Discover, her work appears in Scientific American, Popular Science, New Scientist, Sierra Magazine, Astronomy Magazine, and many more. She graduated with a bachelor’s degree in Journalism from the Grady School of Journalism at the University of Georgia. She’s also a candidate for a master’s degree in science writing from Johns Hopkins University, (expected graduation 2023).