Unit 21 Flashcards
Phytochemicals and genetically modified foods
What are phytochemicals?
Biologically active compounds of plants (protect them from bacteria, animals, and give pigmentation and flavor) believed to reduce risk of chronic disease in humans
Are phytochemicals essential?
No, none of them are, but they are beneficial
How are phytochemicals useful to our tissues?
Have protective and antioxidant properties
Are some phytochemicals toxic to us?
yes
What disease can phytochemicals protect us from?
- cancer
- heart disease
- high blood pressure
- other chronic diesease
The correct balance of phytochemical is unknown, but to get get adequate levels, we need to:
- follow the advice in Canada’s Food guide
- eat a variety: don’t eat the same foods everyday
T/F: phytochemicals can reduce free radicals
True
How do phytochemicals work?
- antioxidant
- hormonal action
- stimulation of enzymes
- protect DNA
- physical action
How do phytochemicals work as an antioxidant?
protect cells against oxidative damage and reduce risk of developing certain types cancer
Phytochemicals as antioxidants
What foods do we find allyl sulfides in?
garlic
Phytochemicals as antioxidants
What foods do we find cartenoids in?
carrots
Phytochemicals as antioxidants
What food do we find flavonoids in?
Berries
Phytochemicals as antioxidants
What foods to we find polyphenols in?
Grapes
What are the hormonal actions of phytochemicals?
isoflavones found in soy imitate human estrogens and help to reduce menopausal symtpoms and osteoporisis
How do phytochemicals stimulate enzymes?
Indoles found in broccoli and cabbage, stimulate enzymes that make estrogen less effective
What type of cancer could broccoli protect against?
breats cancer – make estrogen less effective
How do phytochemicals proctect DNA?
capsacin found in hot peppers, protects DNA from carcinogen
What is the theory behind how cranberries reduce the risk of urinary tract infections?
Some phytochemicals bind physically to cell walls preventing adhesion of pathogens to human cell wall. Proanthocyanidins are responsible for the anti-adhesion properties of cranberries
How many phytochemicals have been identified? What does this mean in terms of supplements?
Up to 10000 have been identified, they cannot all be isolated and put into a supplement
How health benefits of phytochemicals associtaed with foods or supplments?
Foods
What is an example of a phytochemical supplement that can harm health?
beta-carotene, leads to more lung cancer
What is solanine?
The green part of potatoes that occurs when they are exposed to light. This is a natural defense againts insects eating them (bitter)
Symptoms include diarrhea, vomitting, headache, paralysis
What is aflatoxins?
Fungi growing on nuts/peanuts, dried foods, grains, and spices which can cause liver cancer with chronic exposure
What are 2 anti-nutrients?
- oxalic acid
- phytates
Where is oxalic acid found?
Spinach
Why is ocalic acid an anti-nutrient?
bind to calcium and irritate the stomach which can cause kidney stones
Where are phytates found?
Whole grains
Why are phytates anti-nutrients?
Bind minerals (iron and zinc)
What can reduce phytates?
cooking, baking, sprouting, fermentation
What are examples of selective breeding?
- wild corn - use to be only 5 kernals/stalk
- super sweet corn
- leaner animals
- chickens
How many eggs did chickens used to lay a year? How many now?
Used to lay 50 eggs/year
Now 245 eggs/year
What is genetic engineering?
modifying genetic material of living cells so they produce new substances or perform new functions
insert gene from one organism into another
What are some benefits of food biotechology?
- extended shelf life
- efficient food processing
- biopharming
- improved nutrient composition
- gentically assisted agriculture
food biotechnology
What is an example of extended shelf life?
Tomatoes - stay firm longer
- antisense gene
- binds native gene and prevents synthesis of softening protein
- harvested at more flavourdul, nutritious vine-ripe stage (1994-1997)
What is an example of efficient food processing?
- rennin - coagulate milk in cheese
- traditionally from calf stomach
- now massed produced in bacteri – saves time, money, and space
Impossible meat - how does it work?
Contains genetically engineered soy protein and heme protein made from genetically engineered yeast – gives meat taste
Beyond meat does not use GMOs
What is biopharming?
Using animals and plants to produce drugs
What are some examples of biopharming?
- cow produce vaccine in milk
- use banmanas to make edible vaccine
- hydroponically grow tomato plants to secrete desired protein through roots into water
What are some examples of nutrient composition?
- soybeans - upgrade protein quality (why soy is now considered a complete protein)
- canola: increase monosaturated fatty acids
- golden rice: genes from daffodil and bacteria to make beta-carotene
How many child deaths are precipitated by vitamin A deficiency each year?
1.15 million
What percantage of RDA of vitamin A is supplied by 1 cup of golden rice?
50%
What % of canola crops in canada are GM to withstand herbicides?
90-95%
What crops are GM in canada?
- soy
- corn
- canola
- sugar beets
- alfafa
What imported crps are usually GM?
US squash and 80% of hawaiin papayas
What are 3 concerns when it comes to GM food? Explain each briefly.
- Allergenicity: transfer of genes from commonly allergenic organisms to non-allergenic organisms is discouraged
- Gene transfer: gene transfer from GM foods to cells of the body or to bacteria in the GI tract is of concern if the transferred genetic material adversly affects human health (antibiotic resistance genes)
- Outcrossing: migration og genes from GM plants into conventional crops
