Unit 5 Flashcards
structure of vitamins and minerals
vitamins or organic individual units
minerals are inorganic individual units
Function
both do not yield energy, but can assist enzymes to release energy
- vitamins can be broken down, minerals can’t
Food contents
vitamins: micrograms (ug) to milligrams
minerals: micrograms to grams
bioavailability
includes the amount in food, amount absorbed & used by body
Factors:
- efficiency of digestion, time of travel
- nutrient status
- food preparation method
- source of nutrient
- other foods present
precursors
- available for foods in a inactive form
- precursors of provitamin
- converted to the active form in the body
- ex. Vit A,D
solubility
water-soluble: B vitamins, vit C
fat soluble: vit A,D,E,and K
vitamins destroyed
heat, UV and florescent light, oxygen
- veggies in fridge and closed container
- cook veggies for as little time with as little water as possible to keep nutrients
toxicity
more doesnt equal better
- tolerable upper intake levels
- not all have an UL, does not mean they are not harmful if consumed in excess
Nutrient interactions
- presence or absence can influence absorption, metabolism and excretion
1. folate naturally occurs as polyglumate
2. in intestine, digestion breaks down glutamates off and adds methyl group. folate is absorbed and brought to cells
3. in cells, folate is trapped in its inactive form
4. to activate folate, vit B12 removed and keep methyl groups which activated B12
5. both folate coenzyme and the vit B12 coenzyme are now active and availible for RNA synthesis
Nutrients for energy metabolism
- B vitamins
- thiamin
- riboflavin
- niacin
- biotin
- plantothenic acid
- vit B6
- folate
- Vit B12
B vitamins act as coenzymes
- vits and minerals aid enzymes in releasing energy from macronutrients
- b vitamins form part of coenzymes
food sources for B vits
veggies and fruits - folate grain products - thiamin - riboflavin - niacin - folate Milk and Alt. - riboflavinn - B12 Meat and alt - thiamin - niacin - vit B6 and B12
Minerals for energy metabolism
sulphur
iodine
manganese
chromium
the B vitamins
- individually and collectively play a major role in metabolism
- work together and often mask each others deficiency
- water-soluble
- do not contain energy, but w/o them - no energy
- various minerals also contribute to human metabolism
Antioxidant nutrients: overview
- protect cells from oxidative damage
- vitamins quench free radicals
- minerals act as cofactors for enzymes
- oxidation is part of normal metabolism
- unpaired electrons = free radical
- antioxidants neutralize free radicals
Antioxidant vitamins
A, E & C
Vitamin A and Beta-carotene
can overconsume vit A, which is toxic
cannot overconsume beta-carotene, but it can turn your skin orange
- 3 diff forms for vit a
conversion to retinoic acid is permanent
Sources of Vit A and beta-carotene
animal sources are riches - liver, fish, oil. dairy products, eggs Plant - dark leafy greens - yellow or deep orange veggies/fruits
Vit E as an antioxidant
fat soluble
- tocopherals
- primary defende against free radicals
- prevents the from producing more free radicals
- cell membranes and other lipids
reduces risk of cardiovascular disease
4 diff forms: alpha,beta,gamma,delta
primary function: prevent damage of lipids and cell membranes and prevent oxidation of LDL
Sources of Vit E
main source: polyunsaturated plant oils
- leafy green vegetables
- wheat germ
- liver
- egg yolks
- nuts and seeds
Vit C: roles in body
antioxidant - loses electrons easily - gives electrons up to stop free-radical damage - enhances iron absorption cofactor for collagen - facilitates the binding of collagen fibres stress - adrenal glands secrete vit C
Sources of Vit C
fruits and veggies
- citrus fruits
- red bell pepper
- guava
- kiwi
- broccoli
Vitamins A, E and C and selenium
protect cell membranes, lipoproteins, DNA and RNA and proteins
- Vit E and selenium are involved with gluathione peroxidase
- E protects A from oxidation, also important for A absorption
- C regenerated E after it has donated an electron
Vit A and beta-carotene summary
- visions, maitenence of cornea, epithelial cells, mucous membranes, skin, bone and tooth growth, immunity
- retinol: milk and milk products
- beta-carotene: dark green leafy and deep orange
Selenium
Part of an enzyme that defends against oxidation; regulated by thyroid hormones
- seafoods, organ meats, other meats, whole grains, veggies and fruits
What are bones made of?
65% mineral cystals - strength and structural support 35% collagen - flexibility bone mineral density = bone strength
types of bone tissues
cortical bones
- very dense; part of outer walls of larger bones and main tissue of small bones
trabecular bone
- lacy architecture; responses readily to hormones
Bones made of pt 2
phosphorus and calcium
- bone mineral density is measured with DEXA
- bone mineral density is more so trabecular bone
- what responds to hormones to remove or deposit calcium on top of the bone
- lets bones be lighter and spongy
- the denser = the stronger
Osteoperosis
low bone density
osteoclasts and osteoblasts
- cortical bone is on the outside, very hard sense portion of bone.
-mainly on long bones, if all bones were made this way they would be way to heavy
how do bones grow
genetically programmed to grow in length
- conception to teen years
- stops at ~14 years (girl) 17 (boys)
- bone mineral density accrues at the same time into young adulthood
bone remodelling
osteoclast and osteoblast activity
- occurs over a lifetime
- osteoclast>osteoblast activity as we age
- bone is constantly growing and breaking down
- controlled by osteoclasts
- progressive bone loss as we age
Calcium deficiency
active growth plate: birth-20 yrs
peak bone mass: 12-40
final phase: 30+
calcium roles in body
most abundant mineral in body (99%) - forms a matrix on collagen gives strength and rigidity - remodelling occurs continuously 1% in body fluids - extracellular and intracellular compartments
Phosphorous
- 2nd in abundance in body
- phosphate
- combined with calcium = hydroxyputite
- strength in bones
- rarely deficient
- no toxicity effects known
Calcium recommendations
- dairy products
- calcium in other foods
- tofu, nuts, seeds, oysters, fish w small bones
Vit D
in skin + UV light from sun -> pre vit D + heat from body
from diet: vit D2, D3
Vit K
blood clottin bone health (metabolizes osteocalcin and binds calcium to bone)
Vit D recommendations and sources
recommended: assume no vit D from sun. RDA 600iu/day
- sun exposure to 5-10 min 3x a week, skin cancer
- few natural food sources
Iron roles in the body
2 ionic state - ferrous iron -reduced - ferric iron - oxidized Roles: oxidation-reduction reactions - electron carriers in the ETC - part of hemoglobin and myoglobin - carry oxygen in blood and muscle
Iron absorption
iron in food: mucosal cells in the intestinal store excess iron in mucosal ferritin
- if body doesn’t need iron it isn’t absorbed & its secreted. Iron absorbing reducing
- mucosal ferritin released iron to mucosal transferrin, which hands off iron to another
Heme vs. Non-Heme iron
non-heme - 90% of our iron, absorbed at 17%
Heme - 10% absorbed at 25%
foods from animals: heme, also contain non-heme
all of the iron in plants derived from plants is non-heme
Factors that affect iron absorption
enhancers: meat factor, vitamin C
inhibitors: phytates (whole grains, nuts/seeds), vegetable proteins, calcium, polyphenols,
Iron deficiency
most common nutrient deficiency worldwide
- vulnerable stages of life
- growing and preggos
Blood losses
- Gi disorders
- menstration
- blood donationIron recommendations
choose iron-rich foods take advantage or iron-enhancing foods RDA: men- 8mg/day women: 18mg/d vegetarians: 1.8x the iron, lower bioavailability of plant-based
Niacin in your pre workout
- niacin flush - tingling feeling
- also used to lower LDL and increase HDL
- be careful if: liver disease, diabetes, ulcers q
Neural tube defects
neural tube develops during early pregnancy
- folate required for proper formation
- brain & spinal cord developed from this
- CNS disorders and death
- folic acids supplement should be taken prior to conception
Vit A toxicity
hypervitaminosis A
- increased bone tumour
- altered fat-soluble vitamin metabolism
Vit C deficiency
scurvy: inadequate collagen synthesis - hemorrhage
- muscle degeneration, including heart
- rough, brown, scaly skin
- wounds don’t heal
- bones soften, become malformed and painful
- anemia and hysterics
Vit D deficiency
factors contributing to deficiency
- dark skin, breastfeeding, lack of sunlight, not consuming fortified milk
- calcium deficiency
- bones fail to calcify properly, stunted growth and bowed legs
