KNES 337 Final

what is one of the first signs of vit A deficiency

night blindness

What are the classes of lipids

1. triglycerides = glycerol + fatty acid

2. Phospholipids (lipid bilayer such as cell membranes)

3. sterols (cholestrol, vitamin D)

What are triglycerides and why are they important?

They make up ~98% of dietary fat, are the main form of body fat storage, and are used for energy and tissue maintenance.

what determines the type of triglyceride?

The fatty acids it contains—primarily saturated or unsaturated.

How are dietary fats classified, and what are key examples?

• Saturated fats: animal fats (butter, lard), coconut oil, palm kernel oil

  • can raise bad cholestrol (LDL=low density lipoprotein), should be eaten in moderation

• Unsaturated fats:

  • lower LDL, and maintain or raise good cholestrol (HDL= high density lipoprotien)

    • Monounsaturated (Ω-9): olive oil, avocados, peanuts, almonds, canola

    • Polyunsaturated (both essential, must get from diet):

      • Ω-3: EPA/DHA (fish, shellfish), ALA (flaxseed, soybean, walnut, rapeseed)

      • Ω-6: corn, safflower, sunflower oils

Which fatty acids are generally considered beneficial vs cautionary?

Beneficial: Omega-3 (fish, flaxseed, walnuts) and Omega-9 (olive oil, canola, avocados)

Use with caution: Excess Omega-6 (corn oil, sunflower oil)

What are long-chain omega-3 fatty acids and their main health effects?

EPA and DHA; found in high amounts in brain and nervous tissue. They reduce heart disease risk and decrease blood clotting, but very high intake can impair clotting → ↑ bleeding and hemorrhagic stroke risk. Recommendation: fish ~2×/week.

What is DHA’s specific biological role?

DHA is an omega 3 fatty acid that is a structural component of the brain and retina and is essential for intellectual and visual development in late pregnancy and infancy; added to many infant formulas.

Why is the omega-6 : omega-3 ratio important?

High omega-6 intake reduces omega-3 benefits and increases inflammation. Recommended n-6:n-3 ≤ 4:1; typical Canadian intake >9:1, indicating a need to increase omega-3 intake.

Which fats are considered less healthy and why?

Trans fats and saturated fats; they raise LDL cholesterol and are usually solid at room temperature (e.g., meat, lard, block margarine)

Why were modified (hydrogenated) fats invented?

Unsaturated fats are unstable and become rancid with oxygen, heat, and time. Solid fats last longer and perform better in frying, so hydrogenation was developed.

What is hydrogenation and why was it used?

Adding hydrogen to liquid unsaturated oils to make them more saturated and solid, improving shelf life, cooking properties, and taste.

What are the two major drawbacks of hydrogenation?

• Increases saturated fat content (e.g., corn oil 6% → corn margarine 17%)

• Alters fatty acid structure, creating trans fats

What health risks are associated with trans fats?

Formed from partially hydrogenated vegetable oils; they raise LDL, lower HDL, promote inflammation, and are worse than saturated fats. Increased risk of heart disease, stroke, sudden cardiac death, and type 2 diabetes (≈2 g/day increases risk).

What are common dietary sources of trans fats?

Margarine, shortening, peanut butter; deep-fried fast foods; salad dressings, mayonnaise; baked goods (cookies, cakes, crackers, doughnuts); fried snacks & chips.

Where is cholesterol found and where does it come from?

Found only in animal products; plants contain none. Blood cholesterol comes from endogenous synthesis (~2/3 by liver) and dietary intake (~1/3).

Is cholesterol an essential nutrient and does dietary cholesterol raise LDL?

Not essential. Dietary cholesterol has a modest effect on LDL compared to saturated fat, which raises LDL more strongly.

What are the main functions of cholesterol in the body?

Present in every cell; structural component of cell membranes, nerves, and brain; precursor for steroid hormones (estrogen, testosterone), vitamin D, and bile acids.

Can cholesterol be used for energy?

No — provides 0 kcal/g.

Does heart disease affect women and men equally?

Yes, but women on average die 10 years later than men as estrogen is protective before menopause.

List major factors contributing to cardiovascular disease (CVD) risk.

Smoking, menopause, male gender, heredity, lack of exercise, diabetes, central obesity, high LDL/low HDL, hypertension

What causes atherosclerosis and CVD (cardiovascular disease)?

Elevated blood cholesterol & triglycerides and chronic inflammation, which increase plaque formation in arteries.

What is the composition of chylomicrons, VLDL, LDL, and HDL?

Chylomicron = 80% triglyceride, 7% cholestrol, 2% protein

VLDL = 50% triglyceride, 12 % cholestrol, 10% protein

LDL = 10% triglyceride, 50% cholesterol, 25% protein

HDL = 5% triglyceride, 20-50% cholestrol, 50% protein

What role does HDL cholesterol play?

What role does LDL cholesterol play?

HDL: Removes cholesterol from blood, transports it to the liver for excretion; high HDL protects against heart disease.

LDL: Incorporates into arterial plaque, narrows blood vessels; elevated LDL increases heart disease risk.

How can you lower total cholesterol and LDL?

Decrease saturated fat (<10% calories) & trans fat (0 g/day), increase fiber, lose weight if needed.

How can you increase HDL cholesterol?

Increase physical activity, quit smoking, lose weight if needed.

How can you lower triglycerides?

Decrease sugar, alcohol, total fat (<30% calories), lose weight if needed, increase activity.

How are triglycerides transported in the blood, and why are they important for heart disease?

Triglycerides are transported attached to VLDL (very low density lipoprotien, transports triglycerides from liver to tissues for energy and storage). High blood triglyceride levels increase heart disease risk, so prevention and treatment should include managing triglyceride levels.

Why was rickets common during industrialization (1880–1920)?

Coal smoke blocked UV light → ↓ vitamin D synthesis → poor bone mineralization

What dietary pattern led to beriberi in Japanese navy crews?

Diet of polished white rice (nutrients removed with bran/germ, so people didnt get enough thiamin)

What are the classic signs of pellagra and why did it occur in the early 1900s USA?

3 D’s (dermatitis, diarrhea, dementia); corn-based diet with poorly absorbed niacin

Key consequences and early sign of vitamin A deficiency?

Preventable childhood blindness; early sign = night blindness

what is the precursor to vit A in plant foods? what foods is it in? is their an upper limit of it?

beta-carotene
deep orange fruits/veggies, dark green veggies
no upper tolerable limit but high intakes may turn skin yellow-orange

What is pre-formed vitamin A? what kind of food is it in? Where else is it found

retinol
animal products w fat like meat, fish, etc
acne medications; can cause dangerous birth defeccts and even death. cannot be pregnant while taking medication

what is goiter? what can it lead to? what % of the world is at risk

iodine deficiency (need iodine for the production of thyroid hormone)
-leads to hypothyroidism = weight gain, inability to tolerate cold, and fatigue
-also can lead to intellectual disability in children if the mother was deficient during pregnancy
30%

When would we want to maximize bone mass? why

want to maximize during growth years so we can have a sufficient peak at age 30

what are the water-soluble vitamins? what does this allow? whats the exception

vit B and C --> they can wash out of the body in one to several days. however, that does not make them safe in high doses, as that can stress the kidney.
B12 in the exception bc it can be stored for up to one year in the liver

what is oxidative stress caused by

free radicals that are produced in response to normal metabolism using O2; uv radiation; air pollution; tobacco smoke

what are 4 things you can do to minimize nutrient loss?

1. refrigerate fruits and veggies
2. minimize oxidation, reduce contact w air
3. wash fruits/veggies before cutting
4. minimize cooking losses, steam or stir-fry veggies. avoid high temp for long time

folate is the _______ form
folic acid is the _______ form

natural
synthetic

what foods contain folate?
what foods contain folic acid?

leafy green veggies, legumes, lentils
fortified grain products (in canada every bread has it)

Is folate or folic acid more bioavailable?

folic acid

how does a lack of folate effect DNA

how does lack of folate affect the heart health

it reduces DNA stability --> induces and accelerates carcinogenesis
-structure of cell genetic material becomes distrupted --> accumulate abnormalities --> cancer

it causes homocysteine to accumulate in the blood --> heart attacks and strokes

how does lack of folate affect a fetus

Mothers who do NOT consume enough folate → increased risk of neural tube defects (spinal cord and brain deformities)

what are the two most common forms of neural tube defects

spina bifda; treatable
anencephaly; fatal b/c portion of brain and skull missing

what are the intake levels for females, pregnant females, and moms who have a previous child w neural tube defect

females; 400 ug (micrograms)/day
pregnant; 600 ug
previous; 4 mg

What do antioxidants do and why are they important?

Neutralize free radicals → reduce oxidative stress → lower risk of cancer, heart disease, arthritis

what can neutralize free radicals

vit C (antioxidant) along with vit E and other phytochemicals found in fruits and veggies

what are free radicals?

trying to steal an e- from another cell bc they are missing an e- and this can damage the cell membrane (they are like robbers who are deficient in nrg)

how does vit C affect collagen formation? what can happen w vit C deficiency

-helps form collagen (bones, teeth, blood vessels, wounds)
-assists in preventing bruising
-helps scar strength

-vit c deficient = tissue hemorrhage or bleeding can be a symptom

what gland in the body contains lots of Vit C? what does this play a role in

adrenal glands
vit C is released w stress hormones during stress reaction

what are some stressors?

infections, burns, toxic heavy metals, chronic aspirin, barbiturates (sedatives), cigarette smoking, and long term use of oral contraceptives, B12, B6, folate

what have studies shown about smokers and vit C levels

level of vit C can be 7x lower in smokers than non smokers
-this reduces body ability to fight disease, including cancer

what are the Vit C levels for men, females, and smokers

men= 90mg/d
women= 75 mg/d
smokers= +35mg/d

what has some research shown about Vit C effects on a common cold? why may this be happening

1g/day of vit C led to a 1 day shorter cold and reduced severity of symptoms by 23%
-may be happening b/c vit C reduces blood histamine at a dose of 2g/day for 2 weeks

how much vit C do you need to consume to prevent scurvy

10 mg

what can excess intake of vit C cause

nausea, diarrhea, abdominal cramps, excessive gas

what is Vit D role in bone growth

raises blood concentration of Ca and phosphorus by:
-increasing absorption from intestine
-increasing reabsorption from kidneys
-mobilization from bones into blood

what cancers have been shown to decrease w increased vit D intake

breast, prostate and colon all decreased

How does vit D play a role in Multiple Sclerosis/rheumatoid arthritis? how much supplementation should these people take

people living higher than 37 latitude have increased MS risk by >100% b/c they dont get as much sunlight
-400 IU supplementation with decrease risk by 40%

during the summer, how minutes of daily sunlight w forearms and lower legs exposed do white people need and people w darker pigment need to produce sufficient vit D

9 min - ligher pigment
25 min - dark pigment

what are some food sources of vit D

-fortified dairy foods, fortified margarine, fish oils, egg yolk, fluid milk (most reliable source)

T/F its the UV A rays that help w vit D

false; UV b

1. people above 50 latitude, have ___ months w no vit D production
2. people above 40 latitude, have ___ months w no Vit D production

1. 6 months
2. 4 months

reduced production of Vit D can be from what 3 things

-older age; 70+ age = vit d production falls to 30% of younger adults
-institutionalized individuals at high risk (e.g. senior citizens)
-sunscreen reduces or blocks vit D synthesis but not completely (note 15 min exposure early morning/late afternoon w out sunscreen produces all tha is required for a day)

what is the DRI for vit D for adults? what about 70+ year olds?

adults; 600 IU
70+ ; 800 IU

what is the best natural source (food) for vit D

fish (e.g. cod liver oil, salmon, mackerel, sardines)

T/F all the phytochemicals are essential

false; none are

what properties of phytochemicals be useful for tissues? can they be toxic

many have protective and antioxidant properties

some are toxic in large consumption/doses

the biologically active compounds in plants (protect them from bacteria, animals, give pigmentation, flavour) are believed to do what in humans

reduce risk of chronic disease

what diseases can phytochemicals protect humans from

cancer, heart disease, high BP, other chronic disease

do we know the correct balance of phytochemicals? How can we achieve adequate levels?

no its unknown
1. following advice in canadas food guide
2. eat a variety (dont eat same foods everyday)

how do phytochemicals work? (4)

-hormonal action
-stimulation of enzymes
-protect dna
-physical action

explain the hormonal action of phytochemicals? whats an example

isoflavones that are found in soy
-imitate human estrogens and help reduce menopausal symptoms and osteoporosis

explain the stimulation of enzymes by phytochemicals? what an example

indoles that are found in broccoli and cabbage
-stimulate enzymes that make estrogen less effective and could reduce the risk for breast cancer

what phytochemical helps protect DNA

capsaicin found in hot peppers
-protects DNA from carcinogens

explain how phytochemicals have physical action? whats an example

some bind physically to cell walls thereby preventing adhesion of pathogens to human cell walls
-proanthocyanidins in cranberries are responsible for anti-adhesion properties (consumption of cranberries will reduce risk of UTI)

how many phytochemicals are identified? can these all be isolated and put in supplements?

10,000
no

are the health benefits from phytochemicals associated more often with foods or supplements? why

foods
-many supplements arent testing and some phytochemical supplements may actually harm health e.g. beta-carotene

what are 5 benefits of genetic manipulation?

-extended shelf life
-efficient food processing
-biopharming
-improved nutrient composition
-genetically assisted agriculture

how do phytochemicals extend shelf life? give example

-bind to native gene and prevent synthesis of softening protein
-antisense gene (mirror image)
-tomatoes stay firm and ripe longer

What is solanine and when is it found?

toxic compound in green potatoes (light exposure); causes GI and neurological symptoms

What are aflatoxins and why are they dangerous?

oxins from Aspergillus fungi on nuts/grains → ↑ liver cancer risk with chronic exposure

What are oxalates and their health effect?

Bind calcium, irritate stomach, ↑ kidney stone risk

What are phytates and how can their effects be reduced?

Bind iron & zinc; reduced by cooking, sprouting, fermentation

What is genetic engineering?

Direct modification of an organism’s DNA by inserting genes (often from another organism) to produce new substances or functions

How does genetic engineering improve food processing and nutrition?

Microbes make rennin for cheese; GM crops improve fats/protein (canola, soy); Golden rice adds β-carotene

What is biopharming and GM agriculture’s main benefit in Canada?

Drugs made in plants/animals; herbicide-resistant canola (90–95%) allows weed control without crop damage

Main safety concerns with GM foods?

• Allergenicity (no proven effects in current GM foods)

• Gene transfer (e.g., antibiotic resistance)

• Outcrossing (gene spread to non-GM crops)

what are the factors affecting cancer development ho

-genetic factors (affect risk)
-immune factors (may not recognize tumours) —> can be caused by aging, immunosuppressive drugs and viral infections)
-environmental factors
-dietary factors: initiators, promoters, and antipromoters

What are the 4 stages of cancer development?

Initiation: DNA mutation (spontaneous/carcinogen) → Promotion: cell division, abnormal tumor → Progression: more mutations, malignant & invasive → Metastasis: spread to distant sites

what are some dietary carcinogens? what are some of the cancers associated

-some pesticides at high does
-nitrate (preservative found in foods listed below) + amines = nitrosamines (carcinogen)
---- Nitrosamines can be naturally occuring or formed in processing for example: beer, scotch, processed meats (ham, bacon, deli meats, hot dogs)

-stomach, esophagus, liver, bladder cancer

where does alfatoxins (anti-nutrient) come from ? what can it cause? what kind of foods should you disregard

-from aspergillus fungi growing on nuts/peanuts, dried foods, grains, and spices
-can cause liver cancer w chronic exposure
-moldy, discolored or shriveled

where can oxalic acid (anti-nutrient) be found? what does it to

-spinach, turnip greens, rhubarb, beets

-can bind to calcium and irritate the stomach and can cause kidney stones (we dont absorb Ca++ then bc so tightly bound)

what foods is phytates (anti-nutrient) found in? what do they do? what can reduce phytates

-whole grains, legumes, nuts
-bind minerals like iron and zinc (we cant absorb as well)
-cooking, baking, sprouting, fermentation can reduce

how long has selective breeding for animals and crops been happening? what are some examples of selective breeding?

-for centuries
-wild corn = 5 kernals/stalk --> many more now
-super-sweet corn
-leaner animals

chickens used to lay ____ eggs/year and today they lay _____ eggs/year

50, 245

what is genetic engineering? (food biotechnology)? give an example

-modifying genetic material of living cells so they produce new substances or perform new functions (insert gene from 1 organism to another)
-e.g. insert a Bt gene (resistance to harmful insects) from an organism into corn = corn resistant to harmful insects

what does the impossible burger contain? how is this comparable to beyond meat

contains genetically engineered soy protein and heme protein made from genetically engineered yeast

-beyond meat is not genetically modified

what is biopharming? what are some examples? which one did they actually try and what did they find?

use animals and plants to produce drugs
-cow produce vaccine in milk
-hydroponically grow tomato plants to secrete protein through roots in water
-use bananas to make edible vaccine: found that the oral route isnt very effective as intramuscular