Lesson 7 Flashcards
what are the non energy yielding nutrients ?
vitamins and minerals
what are the 4 fat soluble vitamins ?
A, D, E, K
how do our cells metabolize micronutrients for energy ?
they do not
what is nutrient density?
nutrient dense foods have more micronutrients / kcal
what is a micronutrient ?
needs less than 1g a day
micronutrients can lower risk of CVD and cancer, true or false ?
true
what is the AI for alpha-linolenic acid (omega 3) ?
- 6 g/day for men
1. 1 g/day for women
what is the RDA for threonine ?
46g
what is threonine ?
an essential amino acid
what are foods rich in threonine ?
lean beef, soy, pork, chicken, cheese, shellfish, nuts
what is the RDA for thiamin ?
1.1 mg
what foods have thiamin (B1)?
beef, liver, nuts
often foods are fortified w it in rice, pasta
what is the RDA for riboflavin?
1.1 mg
what foods have riboflavin (B2)?
beef liver, lamb
what is the RDA for niacin ?
14 mg
what foods have niacin (B3)
yeast, bran, liver, tuna
what is the RDA for folate ?
400 micrograms
what is the RDA for calcium ?
1000 mg
what are foods high in calcium
milk, kale, sardines
what is the RDA for chromium ?
25 micrograms
what foods have chromium?
yeast, broccoli, wheat
how is vitamin structure different from macronutrients ?
no chains of repeated nutrients. mostly C, H, O, sometimes N and S
what are the 4 natural sources of vitamins ?
plants, animals, fungi, and bacteria
are mushrooms nutrient dense ?
yes !
how are vitamins made in lab ?
by chemists using microbes ?
what is enrichment ?
adding nutrients lost during refinement
what is fortification ?
supplementation of nutrients to food that were not originally present or present in insignificant amount, to reduce risk of specific deficiency diseases
how are vitamins usually classed ?
by solubility
what are the 2 water soluble vitamins
B and C
where are fat soluble and water soluble vitamins stored in food ?
in different parts of the food
how are fat soluble vitamins transported ?
require transport proteins
how are fat soluble vitamins excreted ?
no, they are usually stored with fat
how are water soluble vitamins usually stored ?
they are not, kidneys remove excess in urine
how often do we need water soluble vitamins ?
frequently, 1-3 days
how often do we need fat soluble vitamins ?
in periodic doses (weeks or months)
how are fat soluble vitamins absorbed ?
taken into chylomicron and stored in fatty tissue
why can fat soluble vitamins cause toxicity ?
bc they are less likely to be excreted in urine due to their solubility so they can accumulte in the body
what are the 8 factors deciding the absorption of vitamins
they depend on physiological need
- age
- gender
- diet
- pregnant/lactating
also
- method of preparation
- combination of foods you are
- method of origin (synthetic, etc)
- function
does processed food always become less nutrient dense ?
no, eg tofu
what are the 2 forms of vitamin A
retinols ( that we absorb from animal foods, and then can become retinal or retinoic acid)
beta-carotene (carotenoid pigment), a precursor to retinol
is chlorophyll a carotenoid ?
yes
what vegetables have high vitamin A
carrots, spinach, kale
explain relationship btwn carotene and retinol
12 micrograms of carotene give one microgram of retinol
how is the vitamin content of vit A expresed ?
retinol activity equivalet
does cooking increase or decrease bioavailabiliity of carotene ?
increase, so raw isn’t always better
since beta-carotene is lipid soluble, when will its bioavailability increase ?
if sauteed in butter or oil
what meats contain the most retinol (vit A) ?
cooked liver, fish oil
do we need to eat high vit A everyday
no bc they are stored in the body
why do pregnant women have to limit their vit A consumption by eating liver only once every 2 weeks
vit A stored in liver
is a teratogen in large doses, causing fetus malformation
what are the functions of vit A (3)
cell differentiation, vision, and antioxidant function?
what 3 products are fortified with vit A?
1% and 2% milk
and margarine
(lost when fat is removed)
how does vit A aid cell differentiation ?
maintains healthy cells in mucous membrane epithelial cells, maintains their function and structure
due to vit A aiding cell differentiation, what are signs of vit A deficiency? (3)
increase rate of infection
keratinization of skin
permanent blindness
how is vit A involved in vision ?
transforms light into nerve impulses that inform the brain
the retina cells contain retinal (vit A) which needs to change shape from cis to trans to communicate info in brain
which form of vitamin A does the eye need ?
retinal
what do antioxidants do ?
donate electrons to free radicals
how many carotenoids are there ? how many work as vit A
600
50 are vit A
what are 3 antioxidant carotenoids ?
lutein, zeaxanthin, lycopene
what are the three things needed to make vitamin D ?
sunlight, cholesterol, body heat
what blocks us from synthesizing vitamin d?
sunscreen, pollution, tall buildings, clothing
is vitamin D common in foods ?
no
what is the AI in vitamin D?
600 IU
which food with one serving can get us to our full needed amount of vitamin D?
none
most foods don’t have it or have low amounts, which is why food is fortified with it
which foods will have more vitamin D?
lipid rich foods
what are the three roles of vit D?
bone development, cell growth, cancer fighting
which form of vitamin D do we get from the sun?
previtamin D3
what form of vitamin D do you get from animal diet ?
D3
what form of vitamin D do you get from plant diet ?
D2
what is another word for D3?
calciol
which form of vitamin D is found in the liver ?
calcidiol (from calciol)
which form of vitamin D is found in the kidneys ?
calcidiol from liver becomes CALCITRIOL
when calcium is needed, what happens to vit D forms ?
vitamin D is activated in kidneys
what is the active form of vitamin D?
calcitriol
how does vitamin D affect calcium ?
it increases the bioavailability of calcium
when vit D is lacking, what is the % of calcium absorbed ?
10-15%
with vit D, what does calcium absorption increase to?
80%
how does vit D deficiency affect bone growth?
cells can’t deposit enough calcium to produce strong bone tissue
what is vit D insufficiency called
rickets
what is the main sign of rickets ?
bowed legs
why do vit D deficient kids have bowed legs ?
rickets, means they have trouble carrying their upper body bc bones not strong enough
what is the adult form of rickets ?
osteomalacia: bones become increasingly soft, flexible, and deformed
what happens from too much vit D?
too much calcium.. it’s deposited in soft tissues of body, including arteries and kidneys, causing damage
how can you overuse vit D?
supplements
what do free radicals damage?
the lipid bilayer
what is the main fat-soluble antioxidant found in cells ?
vitamin E
what kinds of foods it vit E found in ?
polyunsaturated vegetable oils, nuts, seeds
what is vit E used in at the supermarket ?
packaged foods to extend shelf life
what 2 diseases does vit E reduce the risk of ?
cancer and CVD
what happens if you are vit E deficient ?
RBC break open, and free radicals destroy LDL
what does vit K do ?
synthesis of blood clotting factors
about half of our vit K requirement is made where ?
in large intestine by bacteria
what age is more likely for vit K deficiency?
infants
why are infants more prone to vit K deficiency?
bc their large intestine is sterile, and there is no vit K in breast milk
what condition are infants prone to ?
Vit K Deficiency Bleeding
how are babies protected against bleeding to death?
vit K shot at birth
which vitamin deficiency will cause us to lack energy, despite adequate glucose ?
B
what vitamin supports generation of energy from macros ?
B
what are the 8 forms of vitamin B ?
Biotin Folate Niacin Panthothenic acid Thiamin Riboflavin Vitamin B6 Vitamin B12
what is the common feature of B vitamins?
they bind to coenzymes
what are coenzymes ?
small molecules that bind to enzymes to activate them
what is the word for B1 ?
thiamin
what Asian food is thiamin found in ?
rice bran (brown rice)
what is Beriberi ?
a disease caused by eating white rice without bran, developed in China from their diet
who can develop Beriberi symptoms ?
mostly poor people and prisoners at risk, but also chickens feeding on leftovers from prisoner’s plates
what are the three main symptoms of Beriberi
weakness, memory loss, weight loss
what is Wernicke-Korsakoff
a neurological disorder typically associated with chronic alcoholism, caused by a deficiency of thiamin
(alcohol-related dementia)
alcohol prevents absorption of thiamin = brain damage
what is B2’s name ?
riboflavin
is riboflavin deficiency rare ?
yes
what are 3 deficiency symptoms of riboflavin (B2)
weakness, inflamed tongue, sores on edges of lips
what causes riboflavin to breakdown ? how does this affect milk packaging ?
exposure to light, so milk stored in cardboard or opaque containers
30 min of UV light will destroy what % of riboflavin (B2) ?
30%
what is B3’s name ?
niacin
what aa leads to niacin ?
tryptophan
`1 mg of niacin = mg tryptophan ?
60 mg tryptophan
where do we get niacin from ?
diet, and tryptophan
what is the niacin (B3) deficiency disease ?
pellagra
what are the three symptoms of pellagra ?
B3 (niacin) deficiency
Dementia
Dermatitis
Diarrhea
what is the difference between pellagra in US and in Mexico?
poor in US were eating corn with low bioavailability for niacin
Mexico: corn soaked in lime which helped free niacin from protein
why is B6 so important
coenzyme for 100 enzymes
which vitamin B is toxic in large amounts ?
B6
what are B6’s main 3 roles ?
energy metabolism, aa metabolism, heme synthesis
which vitamin is necessary for making non-essential aa ?
B6
without which vitamin do all aa become essential ?
B6
vitamin B6 is crucial for what B3 (niacin) reaction?
converting tryptophan to niacin
how is B6 crucial to aa metabolism (2) ?
converts tryptophan to niacin converts homocysteine (toxic) to cysteine
what are the three vitamin that participate in homocysteine metabolism ?
folate, B6, B12
what is homocysteine ?
an intermediate product between methionine (essential aa) and cysteine (non essential)
what does B12 and folate do in homocysteine metabolism ?
convert homocysteine back to methionine to prevent it from accumulating
why does homocysteine contribute to CVD?
causes irritation and inflammation of blood vessels
what is the onset of CVD
inflammation of blood vessels
what is the structure of hemoglobin ?
4 polypeptides
what is heme ?
the nonprotein portion of hemoglobin which holds iron
what is heme found in ?
only animal sources, such as eggs and meat
which vitamin is required for heme synthesis ?
B6
what blood condition happens without B6?
megaloblastic anemia (compromised ability of RBC to carry oxygen)
what are symptoms of anemia ?
fatigue to cardiac arrest
what are three roles of folate ?
DNA metabolism
energy metabolism
aa metabolism
what is the main role of folate ?
DNA metabolism
folate deficiency affects which age mostly ?
embryonic development
folate deficiency causes which 2 defects ?
spina bifida; protrusion of spinal cord outside
anencephaly: brain malformed or missing
carrying twins, at risk of which deficiency ?
folate
what is fortified with folic acid ?
wheat flour
with folic acid fortification in wheat flour, what has happened to rates of neural tube defects ? homocysteine? CVD
neural tube defects ? decrease
homocysteine? decrease
CVD? stayed the same
what vit is necessary for nerve cells ?
vitamin B12
which deficiency would lead to degeneration of spinal cord ?
B12 (maintains myelin sheaths)
how is B12 found in food which reduces its bioavailability?
with proteins preventing its absorption
what releases B12 from its food ?
HCl and pepsin in stomach
which vitamin has a higher bioavailability synthetic than natural ?
B12
in stomach, what happens to B12 ?
HCl and pepsin release it from its protein, and then it binds to intrinsic factor (protein produced by stomach cells)
what happens to B12 once it leaves stomach?
in B12/intrinsic factor complex, reaches ileum where it is absorbed
even with supplements, what is the limiting factor to B12 absorption ?
intrinsic factors
what is pernicious anemia ?
intrinsic factor absence: not being produced, or wrong shape
which age group is B12 deficient ?
over 50 yrs
what is the treatment for pernicious anemia ?
B12 deficiency: monthly injections of B12 or nasal gels/sprays
what 2 vitamin B are abundant in food ?
panthotenic acid and biotin
which vit B can be made partly by bacteria ?
biotin
what is vit C deficiency called ?
scurvy
which foods can cure scurvy ?
fruits w ascorbic acid (citrus fruits)
how is vit C related to protein ?
crucial for synthesis of collagen
without vit C, what happens to protein ?
collagen stops providing structural support, starts being like gelatine
what are the two vitamin antioxidant ?
C (water soluble) and E (lipid soluble)
what population is encouraged to increase vit C intake ?
smokers (antioxidant properties)
which vitamins play essential role in energy metabolism ?
vit B
which 4 vitamins affect blood health?
B12, B6, folate, vit K
which vitamin affects vision ?
vit A
which 3 vitamins affect aa metabolism ?
folate, B6, B12
which 4 vitamins affect growth and development
vitamin A
vitamin D
folate (fetal development)
B12 (neural health)
what 2 vitamins affect DNA metabolism ?
folate
B12
what two vitamins affect bone health
vit C, vit D
what are the three vitamins affecting antioxidants ?
carotenoids,
C
E
are vitamins organic ?
yes
are minerals organic ?
no
what are provitamins ?
form of vitamin which is inactive, often found in food
why are vitamins destroyed in processing ?
bc they are organic
what can destroy thiamin in food
prolonged heating
can refrigeration slow degradation of vitamins ?
yes
what is calbindin ?
a calcium binding protein which needs vit D
in rickets, what happens to ribs
beaded ribs
why is vit D deficiency common in old age ?
skin, liver, kidneys lose capacity to activate vit D, and drink no or little milk, and stay indoors
what is the main risk of vit D toxicity?
kidney stones, calcification in blood vessels which may cause death
what is hypercalcemia ? does it develop from diet ?
high blood calcium, can develop from vit D toxicity but NOT from high calcium intake
what are the best natural sources of vit D?
oily fish
in rickets, what happens to the head?
closing of the fontanel is delayed
how does fiber prevent mineral absorption ?
traps them and carries them out of the body
which 2 naturally occurring compounds can prevent mineral absorption and how ?
phytates and oxalates chemically “bind” or combine with minerals which prevent their absorption
how do you prevent vitamin and mineral loss in vegetables during washing ?
rinse fruits and vegetables before cutting
what happens in the skin when our body absorbs sunlight?
the skin contains 7-dehydrocholesterol which will absorb the sunlight and make previtamin D3 with the UV rays.
