Phytonutrients are natural compounds in plants that provide many functions in the plant itself, such as providing protection from pests and environmental stressors, along with imparting color and distinctive tastes and smells. There are thousands of phytonutrients in nature.
In the human body, phytonutrients stimulate enzymes that help the body get rid of toxins, boost the immune system, improve cardiovascular health, promote healthy estrogen metabolism, and stimulate the death of cancer cells.
Fruits and vegetables are rich sources of phytonutrients (together with whole grains, legumes, herbs, spices, nuts, seeds, and teas). To promote good health and to get the benefits of all phytonutrients, it is important to eat fruits and vegetables of varied color each day, ideally one to two of each color per day.
The Institute for Functional Medicine (2014) 'Phytonutrient Spectrum Comprehensive Guide'