What are Phytochemicals and How Do They Improve Your Health?

For centuries, plant foods have provided humans with both basic nutrition and nutraceutical benefits. However, not until recently did studies firmly prove the nutritional and disease-fighting benefits of eating fruits and vegetables. This is because plant foods of various colors contain a wide range of life-giving minerals and phytochemicals. 


In his book, 5 Colors a Day to Better Health, Dr. Bill Releford explains the nutritional and health benefits of a plant-based diet rich in plant foods of various colors. In this article, we are going to explain what phytochemicals are, and the role the health benefits they provide. 

Phytochemicals, What are they?

Fruits, vegetables, grains, beans, etc., contain bioactive nutrients known as phytochemicals. Phytochemicals (In Greek, Phyto means “plant”) give plants their color, aroma, and flavor. When consumed, phytochemicals or phenolic compounds provide nutritional as well as other health benefits such as reducing the risk of chronic diseases.


Fruits and vegetables with brighter or deeper colors are especially rich in phytochemicals. A larger concentration of these helpful plant compounds is often found in the skins and peels of fruits and vegetables. Research shows that taking phytochemicals in the form of supplements is not as effective as when it is consumed from plant foods. This is because phytochemicals in food sources are easily absorbed compared to those taken in supplement form. 

Phytochemicals Found in Plant Foods and their Health Benefits

Researchers have been able to identify over 4,000 phytochemicals. However, only about 150 of these compounds have been studied in depth. Some of the most beneficial phytochemicals are anthocyanins, flavonoids, antioxidants, carotenoids, sulfides, lycopene lutein, and zeaxanthin. 


Most of the evidence that has been gathered on the health benefits of phytochemicals is based on observing people whose diets are largely plant-based. Scientists have found that these people have significantly lower rates of cardiovascular diseases and certain types of cancer. The following are the phytochemicals in the most-researched fruits and vegetables and their benefits to human health. 

Red Foods— Red Cabbage, sweet red peppers, tomatoes, watermelon

Red plant foods contain lycopene, a carotenoid that is responsible for red pigments. This compound prevents prostate cancer, reduces the damage caused by free radicals, and reduces the negative effects of UV rays on the skin. Lycopene is also thought to play a role in preventing macular degeneration and heart disease.

Orange Foods—Carrots, apricots, sweet potatoes, cantaloupe, pumpkin, squash

Orange plant foods contain a significant amount of carotenoids and beta-carotene that help with night vision, prevent cancer by repairing DNA, and provide the Vitamin A we need. They may also help limit the growth of cancer cells and reduce the risk of heart diseases.

Green Foods - Kale, Broccoli, bok choy, cabbage, spinach, leaf and romaine lettuce, spinach, Brussels sprouts 

Green foods are packed with important minerals and B-complex vitamins. Most green fruits and veggies contain lutein, which is important for eye health. Other phytochemicals found in green foods are indoles and sulforaphane which are known to prevent cancer cell growth by releasing detoxification and antioxidant enzymes that protect substances that cause cancer.

White/Green Foods - Chives, onions, celery, garlic, pears 

Foods in this color category have a variety of helpful plant chemicals. Celery contains organic sodium, an electrolyte that aids fluid balance, which keeps the joint fluids healthy. Onions, chives, and garlic contain allicin, a phytochemical with antiviral and antibacterial effects. Allicin can also help reduce the effects of fatty foods.

Green/Yellow Foods - Green peas, avocado, yellow corn, collard greens, honeydew melon

Yellow and green pigmented foods contain zeaxanthin and lutein, carotenoids that help lower the risk of developing osteoporosis, cataracts, and macular degeneration. Orange and yellow foods are high in Vitamin C, which helps heal the skin. They also help prevent cardiovascular diseases by preventing inflammation and improving circulation.

Red/Blue/Purple Foods - Currants, concord grapes, red apples, prunes, beets, blackberries, blueberries, strawberries, cranberries

Foods in these color categories are especially high in flavonoids that help ward off everyday toxins. Red, blue, and purple foods also contain anthocyanins, a powerful antioxidant that helps to prevent diabetes, neuronal diseases, cancer, and cardiovascular illnesses. Anthocyanins also have anti-aging effects and they help reduce the damages caused by ultra-processed foods.

In Conclusion

Nature has provided us with a plethora of colorful foods with various health benefits. Each plant food has various phytochemicals; broccoli, for example, contains thousands of phytochemicals! All of these phytochemicals have different functions in the body. It is important to note that no single fruit or vegetable contains all the nutrients or can provide you with all the health benefits. This is why you need to include a wide range of fruits, vegetables, whole grains, legumes, and other plant foods in your diet. To get the best concentration of phytochemicals from plant foods, nutritionists recommend that they are lightly cooked.

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