Phytochemicals or phytonutrients are chemical compounds that naturally occur in plants, and have protective, disease-preventing properties.
A variety of these beneficial compounds have been identified by researchers in helping the body to maintain peak health and combat disease, and a growing body of research strongly links the importance of diet to health.
Studies are showing that as we move away from the natural, plant-based diet of our ancestors we succumb to "modern" diseases. Evidence of this can be seen in remote societies who still embrace traditional dietary practices. These people have been reported to live extraordinarily long lives that are free of such illnesses as cancer, heart disease and arthritis.
Here are a few ways in which these beneficial compounds protect human health:
Phytonutrients are grouped into classes depending on their protective functions as well as individual physical and chemical characteristics of the molecules. Each class offers a unique kind of protection for the body. But for overall health, all classes of phytonutrients should be consumed, and an easy way to boost phytonutrient intake is to simply eat a mix of naturally colorful foods.
Here are the main classes of phytochemicals and some of their individual health-boosting properties.
These phytonutrients form a large class that have been the subject of extensive research as a disease preventive. Phenols protect plants from oxidative damage and perform the same function for humans. Food sources rich in polyphenols include onion, apple, tea, red grapes, grape juice, strawberries, raspberries, blueberries, cranberries, and certain nuts.
Terpenes are one of the largest classes of phytonutrients and are found in green foods, soy products and grains. The most popular terpenes are carotenoids, such as Beta-carotene. Terpenes function as antioxidants, protecting lipids, blood and other body fluids from attack by free radicals, which cause disease.
Other investigations have revealed that phytosterols block the development of tumors in colon, breast and prostate glands.
Found in cruciferous vegetables, glucosinolates are powerful activators of liver detoxification enzymes. They also regulate white blood cells which coordinate the activities of all immune cells. Their actions involve blocking enzymes that promote tumor growth, particularly in the breast, liver, colon, lung, stomach and esophagus. Some examples of foods containing glucosinolates are broccoli, cabbage, garlic and mustard.
This subclass includes phytonutrients that interact with Vitamin C, and the vegetables that contain indoles also contain significant amounts of Vitamin C. Indole binds to carcinogens and activates detoxification enzymes.
Garlic and onions are the most potent members of this class, which also includes leeks, shallots and chives. The allylic sulfides in these plants are released when the plants are cut or smashed. As a group, allylic sulfides appear to possess antimutagenic and anticarcinogenic properties as well as immune and cardiovascular protection. They also appear to stop the growth of tumors, fungi, parasites and cholesterol. Garlic and onions, like their cruciferous relatives, can also activate liver detoxification enzyme systems.
A growing body of research has linked the consumption of fruit and vegetables and other foods that are naturally high in phytochemcials with lowering the risk for chronic diseases including specific cancers and heart disease, and protecting health in general. Therefore an effective way to boost health and reduce the risk of cancer and heart disease is to increase consumption of phytonutrient-rich foods including fruits, vegetables, grains and teas.