Phytochemicals are non-nutritive plant chemicals that have protective or disease preventive properties. They are non-essential nutrients, meaning that they are not required by the human body for sustaining life. It is well-known that plant produce these chemicals to protect themselves but recent research demonstrate that they can also protect humans against diseases. There are more than thousand known phytochemicals. Some of the well-known
phytochemicals are lycopene in tomatoes, isoflavones in soy and
flavanoids in fruits. There are many
phytochemicals and each works differently. These are some possible actions: Antioxidant - Most
phytochemicals have antioxidant activity and protect our
cells against oxidative damage and reduce the risk of developing certain types of cancer.
Phytochemicals with antioxidant activity: allyl sulfides (onions, leeks, garlic), carotenoids (fruits, carrots), flavonoids (fruits, vegetables), polyphenols (tea, grapes).Hormonal action - Isoflavones, found in soy, imitate human
estrogens and help to reduce menopausal symptoms and osteoporosis. Stimulation of
enzymes - Indoles, which are found in cabbages, stimulate
enzymes that make the
estrogen less effective and could reduce the risk for breast cancer. Other phytochemicals, which interfere with enzymes, are
protease inhibitors (soy and beans),
terpenes (citrus fruits and cherries).Interference with DNA
replication - Saponins found in beans interfere with the
replication of cell DNA, thereby preventing the multiplication of
cancer cells. Capsaicin, found in hot peppers, protects DNA from carcinogens. Anti-bacterial effect - The phytochemical allicin from
garlic has anti-bacterial properties. Physical action - Some
phytochemicals bind physically to cell walls thereby preventing the adhesion of pathogens to human cell walls. Proanthocyanidins are responsible for the anti-adhesion properties of cranberry. Consumption of cranberries will reduce the risk of urinary tract infections
Relevant Topics in General Science
