Phytochemicals
•Medicinal properties of food have a long history – “Let food be thy medicine and medicine be thy food”
(Hippocrates 2500 years ago)
•Almost all cultures use plants as a part of healing, either food plants or herbs
DEFINITION
•In the last 20 years, there has been an explosion of research into other “nutrients” in food
•We are now aware that there are many compounds found in foods that can have a biological effect, but
are not part of normal metabolism
•These compounds are often found in plants (hence the name “phyto”)
More than 900 different phytochemicals have been identified as components of food
It is estimated that there may be more than 100 different phytochemicals in just one serving of vegetables
FUNCTION
•Plants contain phytochemicals because they are beneficial to the plant. For example:
•Carotenoids are produced by plants as photosynthetic pigments and as reproductive compounds (by
attracting insects)
•Flavanoids are involved in nitrogen fixation
•Terpenoids are toxic to insects
•Others help to resist attacks of bacteria, and defend against free radical attack
What Is So Exciting About Phytochemicals?
•Inhibit various hormone actions and metabolic pathways that are associated with the development of
cancer and heart disease
•Some phytochemicals have been found to lower LDL cholesterol, or prevent blood clotting
•Others have been found to have powerful antimicrobial properties
•Many function as antioxidants
ANTIOXIDANTS
 A certain amount of free radical formation is a normal part of metabolism
 Free radicals can damage the basic structure of cells and thus lead to chronic diseases (notably cancer
and heart disease) and accelerate the aging process
 Antioxidants help deactivate free radicals
 Plants are vital sources of antioxidants for humans and other animals
 Humans also make their own: glutathione peroxidase, superoxide dismutase
Factors that increase free radical damage include high levels of energy expenditure, exposure to sunlight
and oxidative pollutants, and inadequate dietary intake of antioxidants
Phytochemicals In Foods
Tomatoes, Watermelons, Grapefruit, Guava
 Phytochemical found: Lycopene (carotenoid)
 Lycopene has been found to be 2 times as powerful as beta carotene in the destruction of free radicals
 Consumption of lycopene has been associated with a decreased risk of prostate cancer
Cruciferous vegetables: broccoli, cauliflower, cabbage, dark leafy greens
 Phytochemicals found are: Indoles
 May help prevent certain types of cancer
 Breast cancer: inhibits estrogen-induced growth of cancer cells and converts the more dangerous forms
of estrogen to safer forms
Onions, Garlic, Scallions, Chives
 Phytochemicals Found: Allium compounds
 They help to keep healthy cells in the body from being damaged by free radicals
 Antimicrobial effects
More Research on Garlic
 Trials show several promising, modest, short-term effects of garlic supplements on lipid and
antithrombotic factors
 Effects on clinical outcomes are not established, and effects on glucose and blood pressure are none to
minimal
 High dietary intake of garlic may be associated with decreased risks of multiple cancers
www.americanheart.org
Raspberries, Strawberries, Walnuts, Blackberries, Grapes
 Phytochemicals found: Ellagic Acid
 Appears to make blood less likely to clot therefore is beneficial in preventing heart disease.
 Early evidence shows that ellagic acid acts as a scavenger to "bind" or chemically engage cancercausing chemicals, making them inactive.
Spinach, Kale, Leeks, Peas
 Phytochemical found: Lutein
 Lutein is concentrated in the retina and lens of the eye
 May protect against age-related macular degeneration, the leading cause of blindness in people over 65.
http://www.eyesight.org/Adult/adult.html
Soybeans
 Phytochemicals found: Isoflavones (coumesterol, genistein)
 Research suggests that soy isoflavones benefit humans in four ways: as phytoestrogens, as cancerenzyme inhibitors, as antioxidants, and as immune system enhancers or stimulants.
Green Tea: contains high levels of flavanoids
 Shuts off the formation of cancer cells
 Turns up the body’s defense system and suppresses cancer advancement
 Has also been indicated to lower LDL, increase HDL in large quantities
 Anticariogenic effects
Phytochemical Supplements
•There are some available, but remember: They will only provide selected components in a concentrated
form, and not all of the compounds that occur naturally in foods.
Is There A Negative Side?
•Some studies on animals containing large amounts of phytochemicals have had negative results (from
supplements)
•CARET study
•Optimal levels of phytochemicals have yet to be determined
How Can You Increase The Phytochemicals In Your Diet???