when you thought you'd learned everything there is to know
about anti-oxidants, you may have started reading reports
about phytochemicals. Don't
panic -- phytochemicals may sound futuristic, but the name is just the most recent label emphasizing the plant source of most of these protective compounds. What is "new" about phytochemicals is recent research about the disease preventing possibilities they hold.
Phytochemicals are certain organic components of plants which scientists have isolated as being beneficial to human health in a different way from traditional anti-oxidants. They are sometimes referred to as phytonutrients, but unlike the traditional nutrients (protein, fat, vitamins, minerals), they are not "essential" for life so the term phytochemical is more accurate. Still, a true nutritional role for phytochemicals is becoming more probable every day as researchers uncover more and more benefits. It is possible that phytochemicals may indeed someday be classified as essential nutrients.
Phytochemicals have proven to be beneficial in many ways. They may serve as anti-oxidants in a bodily system when required; for example, the phytochemical beta-carotene can metabolize to create vitamin A, a powerful anti-oxidant. Additionally, phytochemicals may enhance immune response and cell-to-cell communication, allowing for the body's built-in defenses to work more efficiently. Phytochemicals may even alter estrogen metabolism, cause cancer cells to die (apoptosis), repair DNA damage caused by smoking and other toxic exposure, and detoxify carcinogens by working with bodily enzymes.
Some of the common classes of phytochemicals include carotenoids, flavonoids, phenols and terpenes. Of all the phytochemicals, we probably know the most about carotenoids, the red, orange and yellow pigments found in fruits and vegetables. Carotenoids are actually a subclass of a phytochemical called terpenes, probably the most common of all the phytochemicals. Terpenes can be found in almost all plant life and have a beneficial function within plants themselves; in humans, they also seem to battle against certain cancers and even heart disease. The subclass carotenoids include alpha- and beta- carotene, beta-cryptoxanthin, and lutein, found in carrots, leafy green and yellow vegetables, and citrus or pulpy fruits. Another cartenoid, lycopene, is found heavily in tomatoes. There have been several studies suggesting that these compounds are among the most beneficial components of fruits and vegetables.
Polyphenols are another common phytochemical and generally come in two classifications: flavonoids and non-flavonoids. Found in strawberries, blueberries, raspberries, teas, and soybeans, polyphenols appear to fight allergies, inflammation, free radicals, hepatotoxins, platelet aggregation, microbes, ulcers, viruses and tumors. Some sub-classes of polyphenols also inhibit specific enzymes; for example, flavonoids block the angiotensin-converting enzyme (ACE) that is responsible for raising blood pressure. Flavonoids also protect the vascular system and strengthen the tiny capillaries that carry oxygen and essential nutrients to all cells.
Our understanding of phytochemicals is still in its infancy, but research in this area is expanding rapidly because it appears that phytochemicals offer a measurable amount of protection against oral cancer and other diseases. Will phytochemicals be the preferred "prescription" of tomorrow? Possibly, but in any case they are helping teach us more about natural defenses against cancer, and that is a good thing by any name.