Transcript Key Terms Phytochemicals

Judith E. Brown
www.cengage.com/nutrition/brown
Phytochemicals and
Genetically Modified Food
Unit 21
Prof. Albia Dugger • Miami-Dade College
Phytochemicals
• People who eat lots of fruits, vegetables,
whole grains and other plant foods are less
likely to develop many health problems
• Plants contain thousands of potentially
beneficial substances called phytochemicals
Key Terms
• Phytochemicals
• Chemical substances in plants which likely
perform important functions in the body
• Zoochemicals
• Chemical substances in animal foods which likely
perform important functions in the body
Nutrition Superstars
Some Phytochemicals
Characteristics of Phytochemicals
• Functions in plants:
• Provide color and flavor
• Protect from insects, microbes, oxidation
• Used in energy processes, hormones
• Not all phytochemicals are healthful
• Naturally occurring toxins
Phytochemicals and Health
• Diets rich in phytochemicals protect against
many diseases
• Heart disease, certain cancers, infectious
diseases, osteoporosis, type 2 diabetes, stroke,
hypertension, cataracts, age-related macular
degeneration, and other disorders
Age-Related Macular Degeneration
• Age-related macular degeneration
• Eye damage caused by oxidation of the macula
(central portion of eye responsible for detail)
• Leading cause of blindness in adults over 65
• Prevented by carotenoids (antioxidants)
Cataracts
• Cataracts
• Complete or partial clouding of the lens of the eye
Phytochemicals Work in Groups
• Most (if not all) phytochemicals work together
when consumed at the same time
• Pills containing individual phytochemicals
don’t have the same effect
Beta-Carotene Studies
• Smokers with high beta carotene levels from
fruits and vegetables had low cancer rates
• Smokers who took beta carotene
supplements had higher cancer rates
• Conclusion: A combination of chemicals in
plant foods reduced cancer
Plants Beat Pills
Vegetable Extracts and Essences
• It would take 100 pills to
get the same amount of
just one phytochemical
(sulforaphane) in one
serving of cruciferous
vegetables such as
broccoli
Key Terms
• Cruciferous vegetables
• Sulfur-containing vegetables whose outer leaves
form a cross (crucifix)
• Includes broccoli, cabbage, cauliflower, brussels
sprouts, mustard, collard greens, kale, bok choy,
kohlrabi, turnips, broccoflower, and watercress
How Do Phytochemicals Work?
• Phytochemicals can:
• Act as hormone-inhibiting substances to prevent
initiation of cancer
• Act as antioxidants that prevent and repair
damage due to oxidation
• Neutralize enzymes that promote cancer
• Modify utilization of cholesterol
• Decrease formation of blood clots
Phytochemicals
Phytochemicals
Top Antioxidants
• Bright-colored pigments
are strong antioxidants
• Zeaxanthin
• Anthocyanin
• Lycopene
Naturally-Occurring Food Toxins
• Solanine
• In green potatoes
• Oxalic acid
• In dark green, leafy
vegetables
• Cyanide
• In cassava
Naturally-Occurring Food Toxins
• Ackee fruit
• Part edible, part deadly poison
Caffeine
• Caffeine is a habitforming phytochemical
• Withdrawal can cause
headaches
Genetically Modified (GM) Foods
• Genetic engineering
• Process of biotechnology used to modify the
composition of a food by altering its genetic
makeup – includes transfer of genes from one
species to another
• Food products produced are sometimes called
GM or GMOs (genetically modified organisms)
Genetic Modification of Plants
Genetic Modification of Animals
• Biotechnology has also genetically
engineered animals used for food
• Atlantic salmon, pigs, cattle, chickens
• Animal products from cloned animals make
up a small fraction of meat sales
Are GM Foods Safe?
• Over 60% of processed foods contain GM
ingredients
• 80% of soybeans, 30% of corn are GM
• Tomatoes, squash, cantaloupe, potatoes
• Organic produce is not GM
GM-Free Foods
Benefits and Concerns of GM Foods