Chapter 10-Micronutrients Flashcards
what are the two types of micronutrients
organic vitamins
inorganic minerals
which two vitamins play a role in body tissues ?
vit C and D
which three minerals play a role in body tissues ?
Ca, P, F
which vitamin group is a cofactor for enzymes ?
vit B
which two minerals are cofactors for enzymes ?
Zinc, Mg
which mineral is crucial for oxygen transport ?
iron
which two vitamins are important for oxidative metabolism ?
niacin, riboflavin
which 3 vitamins are antioxidants ?
vit C, vit E, beta carotene
which two minerals are antioxidants
copper-manganese as part of SOD (superoxide dismutase)
and selenium as part of GSSH (gluthatione)
what are 4 methods to assess nutritional status ?
ABCD anthropometrics- waist circumference, weight biochemical- blood tests clinical- physical exam dietary- 24 hr recall
what is the advantage of biochemical tests ?
usually detect nutrient discrepancies before altered anthropometrics and clinical signs and symptoms
are physical signs of deficiency reliable ?
not really, always do blood tests
blood work is not relevant for which mineral
Calcium
what is a disadvantage of blood work ?
some signs are non-specific
what are two examples of non-specific signs ?
swollen corners of the lips
angular stomatitis/ angular cheilitis
what can angular stomatitis/ angular cheilitis be caused by? which deficiencies (4)
vitamin B
PEM (protein)
iron
zinc
what is the normal color of the tongue ?
light red
what is glossitis ?
smoothening of the tongue where it is usually covered with taste buds
glossitis can be a sign of which deficiencies (6 vit, 2 minerals, 1 other thing)
riboflavin niacin biotin vit B6 vit B12 folate
iron,zinc
drug-nutrient interactions
pallor in tongue is a sign of which deficiency (3 vit, 2 minerals)
folate, biotin, vit B12
copper, iron
what is inadequate intake
low variety, low cal, very low fat
what disorders cause nutrient deficiencies
crohn’s, celiac
what condition alters metabolism to the point where there might be a nutrient deficiency
alcoholism
is there true evidence that consuming micronutrients in excess of RDA improves performance ?
no
which three vitamins can in part be produced by the body ?
vitamin D (sunlight) K and selected B which can be produced by the bacterial microflora
how do vitamins directly contribute to energy supply ?
they do not !
which vitamin deficiency causes premature fatigue and inability to maintain a heavy training program ?
B
which two vitamins are crucial for maintaining healthy populations of cells (eg RBC)
folic acid and B12 (because they are involved in nucleic acid synthesis)
which vitamin is important for blood clotting ?
K (glycoproteins)
what are 5 rolels of micronutrients ?
structural enzyme and cofactors in metabolism of macros antioxidants and immune function electrolytes and acid-base balance nerve transmission, muscle contraction
is more vitamins better ? what is the proof ?
no, since we have an Upper Limit for many nutrients
what is vitamin intake correlated with? what does it mean ?
it is correlated with energy intake, meaning that you shouldn’t become deficient with energy intake equal to estimated requirements
does physical activity increase requirement of vitamins ? what are the implications ?
yes for some: C, riboflavin, and maybe others. but can be met by consuming a high carb, moderate protein, low fat diet.
how does one compensate vitamin losses in sweat, urine, and feces ?
you don’t need to, the losses are negligible.
how does exercise affect vitamin turnover ?
it doesn’t
physical activity may increase the requirements of which B vitamins? why?
(B2) riboflavin and B6
due to increased retention of those in skeletal muscle mitochondria for energy metabolism
physical activity may increase the requirements of which class of vitamins ?
antioxidants, due to increased free radical production during exercise
what are the three free radicals produced by oxidation in the mitochondria ?
superoxide, hydroxyl, nitric oxide
are vitamins organic or inorganic
organic
are minerals organic or inorganic
inorganic
what element do minerals not contain
C
what 4+ elements do vitamins contain
C, H, O, N
and metal ions (copper, iron, sulfur, cobalt)
how many identified vitamins ?
13
how many minerals are essential for humans ?
20
how are vitamins classified ?
by solubility
how are minerals classified ?
macro and micro minerals
do vitamins and minerals take part in body mass ?
vitamins, no
minerals, yes
are vitamins structural ?
no
which three minerals are structural ?
calcium, phosphorus, fluorine
what is the only water soluble vitamin stored ?
B12
which type of vitamin is mostly required from the diet ?
water soluble
what are the three sources for fat soluble vitamins ?
diet, gut bacteria (K), sun (D)
what are the 7 macrominerals ?
CCMPPSS
Chloride Calcium Magnesium Phosphorus Potassium Sodium Sulfur
what is the abbrev for 7 macrominerals ?
CCMPPSS
which 3 minerals are used for enzymes ?
magnesium, copper, zinc
which two minerals are crucial for immune cells ?
iron and zinc
why is it that vitamin needs of physically active people generally do not exceed those of sedentary people ?
because vitamins are recycled in body
what are the 3 causes of fat-soluble vitamin deficiencies ?
malabsorption : surgical or medical causes (like intestinal resection, or lack of fat digestive enzymes in pancreas)
GI or hepatic disorders
low cal diet (<700kcal /day)
what are the main 3 roles in the body of vit A ?
maintain epithelial tissues in skin, pigments of eye
bone development
immune function
what is the scientific word for vit A ?
retinol
what are three consequences of vit A deficiency ?
night blindness, infections, impaired growth
what are effects of excess vit A ?
nausea, joint pains, peeling skin, abnormal fetal development
what is the word for the primary form of vit D ?
calcitriol
what are two deficiency diseases of vit D ?
rickets in kids
osteomalacia in adults
what is a consequence of vit D toxicity?
hypercalcemia meaining calcification of tissues eg kidneys, arrhythmias, depressed CNS, constipation (as well as nausea, loss of appetite, etc)
what is the word for vit E ?
alpha-tocopherol
what is the main role of vit E
antioxidant
what is the main consequence of vit E deficiency? what are three consequences ?
cell membrane damage
meaning muscle weakness, hemolytic anemia, loss of motor coordination
what is the main role of vit K ?
forms glycoprotein blood clotting factors
what happens w a vit K deficiency?
hemorrhage
what is a consequence of vit K excess ?
thrombosis
what is the main consequence (medical) of a vit A deficiency?
keratinization of skin, meaning immature skin cells (keratinocytes) do not mature and can’t secret mucus, so they secrete keratin and become hard.
this can cause hyperkeratosis, blindness, etc
what are our two sources of vit D ?
diet and sun
explain how sunlight becomes calcitriol in vit D
D3 (cholecalciferol) goes to liver, becomes CALCIDIOL
liver CALCIDIOL becomes kidney CALCITRIOL with the help of parathyroid hormone
how does diet vit D become calcitriol ?
D3 and D2 go into chylomicrons to liver, become CALCIDIOL, converted to CALCITRIOL in kidneys
what are the three areas of the body with vit D calcitriol receptors ?
intestines, bones, other tissues
what does calcitriol do to the intestine ?
increases absorption of calcium and phosphorus
what does calcitriol do to bone
assists parathyroid hormone in stimulating osteoclasts to break down bone and release calcium into blood
how does calcitriol affect tissues other than bone and intestine ?
aid cell differentiation and inhibit cell proliferation
can you get vit D excess from sun ?
no
what population has a vit D deficiency ? for what three reasons
North Americans above 30degN latitude
sun not strong enough in winter, in summer cover up due to cancer risk
older adults
dark skinned individuals
how much sun required per day to avoid vit D deficiency?
5-30 min
where is vit E stored ?
adipose tissue and cell membranes ?
what are the different forms of vit E ?
8 forms with varying biological activity
only 1 form (alpha tocopherol) needed in humans
what dose would cause an excess of vit E?
> 400 IU/d
use of what medication could contribute to a vit K deficiency ?
antibiotics
what does vit K do precisely on a structural level
adds sugars to proteins
which fat-soluble vitamin has an RDA, not an AI? what is it ?
vit D
has an RDA of 15 micrograms/d for both males and females
what are the main two roles of water soluble vitamins ?
cofactors in energy metabolism
participate in DNA and RNA metabolism
what are the three main signs of water soluble vitamin deficiency?
premature fatigue, unable to maintain heavy training, slow wound healing
why dont water soluble vitamins usually cause toxicity?
because body doesn’t store them
which vitamin deficiency can cause lip sores ?
riboflavin
which vitamin deficiency causes beriberi ?
thiamin
what is the main role of vit B?
form coenzymes
what is the main role of vit C
antioxidant
what two things does vit C increase
collagen formation and iron absorption
which vitamin is crucial for protein metabolism ?
B6
which 3 vitamins crucial for glycogen metabolism?
thiamin, niacin, B6
what is another word for B6 ?
pyridoxine
which 5 vitamins are precursors to CoA?
riboflavin, niacin, thiamin, panthothenic acid, biotin
which two vitamins are involved in redox reactions in TCA cycle ? how ?
niacin: NAD, NADP
riboflavin: FAD, FMN
what are the three consequences of vit C excess ?
diarrhea, urinary stone formation, impaired copper absorption
what is vit C deficiency called ? what are 3 symptoms ?
scurvy
bleeding gums, infections, slow wound healing
what muscle pain reflects thiamin (B1) deficiency?
pain in calf muscles
what are 4 main symptoms of thiamin deficiency
mental confusion
pain in calf muscles
muscle weakness
nerve degeneration
where is Beriberi more common and why
Asia, because thiamin found in husk of rice which they remove
how long does a thiamin deficiency have to be left untreated for it to cause serious damage ?
10 days
what are the two types of Beriberi
dry and wet
dry affects the PNS
wet affects the cardiovascular system, etc
what are the symptoms of dry beriberi
emaciation
damaged nerves, paralysis
what is an early sign of beriberi
paresthesia (tickling, numbness in limbs)
what are the symptoms of wet beriberi
dyspnea, edema, etc
what condition can affect thiamin deficiency?
alcoholism
what are two causes of niacin deficiency ?
alcoholism, PEM
what is a visible sign of niacin deficiency ?
glossitis, angular cheliosis
what is the niacin deficiency disease and its 4 symptoms
Pellagra
DIarrhea, Dermatitis, Dementia, Death
at what point of excess does a niacin toxicity show and how ?
x10 RDA
flushing of skin around face and neck
which vitamin are vegans at the most risk of deficiency of ?
B12
which B vitamin is the only one not to be found in all foods ?
B12 (mostly in meat)
true or false: most B vitamins can be found in all food groups
true
what are the two sources of niacin ?
food and body tryptophan
which molecule forms niacin in the body
tryptophan
what kind of intake is needed for a mineral to be considered major or minor ?
major >100mg
minor <100 mg
why is it easy to get a mineral toxicity from supplements ?
because minerals are tougher to flush out than vitamins
does the GI tract absorb more minerals than vitamins ?
no
what are three molecules which affect mineral absorption ?
fiber
phytates
tannins
(bind to minerals)
what would you recommend to an anemic who has osteoporosis ?
to take iron and calcium supplements together because iron competes with calcium
what is the main factor affecting mineral absorption ?
bioavailability
what happens to minerals in the blood
go to tissues, or are chelated (bound) by plasma proteins
what are 4 things which increase mineral bioavailability
deficiency (an anemic can absorb more iron)
cooking (beta-carotene)
vitamin C
vitamin D
which two vitamins increase mineral bioavailability
vit C and vit D
which 4 things decrease mineral bioavailability
binders (phytates and oxalates)
high supplement doses of a mineral (limited capacity of absorption)
polyphenols (tannin)
high fiber diet
which 4 minerals are involved in muscle contraction ?
calcium
potassium
phosphorus
sodium
what are the roles of calcium ?
bone and teeth formation
muscle contraction
nerve impulse transmission
what are the 3 effects of calcium deficiency ?
osteoporosis
impaired muscle contraction
muscle cramps
what is the effect of excess chlorine and with what compound especially in combination ?
chlorine + sodium = hypertension in excess
what is the main role of chlorine ?
hydrochloric acid formation in stomach
what is the main role of magnesium ?
bone component
what is the main role of potassium ?
membrane potential, muscle contraction
what is the main role of phosphorus ?
bone formation and muscle contraction
what are the two main roles of sodium ?
muscle contraction and blood volume homeostasis
which mineral is responsible for acid-base balance ?
sulfur
which mineral has an RDA, not an AI anymore ? what is it ?
calcium
1000 mg/day
what is the role of copper
iron absorption
B12 combines with what mineral for RBC formation ?
cobalt
what does fluorine do ?
teeth formation
which mineral is a precursor to T3 and T4
iodine
which mineral transports oxygen
iron
what is the role of selenium ?
antioxidant in cofactor with glutathione peroxidase
a goiter occurs from which deficiency ?
iodine
supplementation of minerals should not exceed what
2x RDA
are losses in minerals in sweat, feces, urine negligible ?
no, have to replace
minerals can be found in animals apart from which two ?
iodine and manganese
what are the 4 minerals and 3 vitamins which help with building ?
calcium, magnesium, phosphorus, fluorine
vit D, vit K, vit C
how do vit D, K, C help with bone formation
vit D increases calcium absorption, increases osteocalcin
vit K activates osteocalcin (bone formation
vit C increases collagen formation
what happens with low blood calcium ?
bone demineralization
Ca mobilized and brought to blood
what happens with high blood calcium ?
blood gives calcium to bone (mediated by calcitonin and vit D, increase calcium uptake, increase in osteoblasts, etc and then PTH and osteoclasts)
gives calcium to kidneys too, excrete in urine and reabsorb if needed
is calcium proportional to energy intake
yes
what is the female triad ?
low energy
amenorrhea
osteoporosis
what three vitamins and 4 minerals are antioxidant
C, E, A (beta carotene)
selenium
copper
manganese
zinc
what is an antioxidant
donate electron to free radical
what is ROS ? what does it do
reactive oxidant species or free radical
leads to lipid peroxidation
what produces ROS ?
alcohol, smoking, UV light, normal cell metabolism, oversupplementation of minerals
which diet produces ROS
high fat diet
which two enzymes come in and destroy ROS ?
superoxide dismutase and catalase
what happens when there are too many free radicals ?
antioxidant cascade: antioxidants become free radicals themselves aided by reductase and peroxidase
what is the argument for supplementing antioxidants in exercise ?
exercise increases ROS in skeletal muscle
why is it bad to supplement with antioxidants in exercise to suppress ROS ?
because ROS may be a signalling molecule and aid in training adaptations
why may it be unnecessary to supplement with antioxidants ?
because training activates antioxidant defense
regular exercise decreases disease risk
megadoses may cause toxicity
and a balanced diet will give you sufficient intake
what delivers iron to tissues ?
transferrin
iron goes to which 4 places ? why ?
muscle (to form myoglobin)
bone (to form hemoglobin and RBC)
liver (for storage)
tissues (to make heme)
what is the molecule which mostly binds to iron ?
ferritin
what happens to most iron ?
it is recycled to make new RBC or is stored
some is lost
what is heme ?
iron-containing portion of Hb and Mb
what are 2 factors influencing iron absorption ?
iron status
GI function
type of iron source
nutrient interactions
in what iron status will you be able to absorb more iron ?
low iron status (so anemics can absorb more)
how does GI function affect iron absorption ?
low gastric acid means less iron absorption
acids help dissolve iron
how does type of iron source influence iron absorption ?
heme iron (Fe2+) is more readily absorbed, found in meat and animal products
non-heme (Fe3+) mainly in plants
how can you enhance non-heme iron absorption ?
consume vit C-rich foods
consume heme iron foods (animal meat)
which factos decrease iron absorption (6)
polyphenols (tannins in tea and coffee)
oxalates (in spinach, chocolate)
phytates (grains and legumes)
excess fiber
soy
high intakes of micronutrients
which sex is more likely to develop an iron deficiency
women
what are the three stages of iron deficiency ?
1) iron depletion in bone marrow, with a reduced plasma ferritin concentration of under 12 ug/L and no physical symptoms
2) erythropoeisis decrease and decrease in heme production but RBC and Hb still normal
decrease in work capacity and physical performance
3) anemia : RBC and Hb abnormal
what do you call the RBC in anemia
microcytic and hypochromic
in anemia, how low is Hb ?
<120g/L
in anemia, how low is hematocrit ?
<36%
what are symptoms of iron deficiency anemia ?
pale skin, low energy, etc
what is the first thing you should do when you suspect anemia ?
get checked BEFORE getting supplements
which athletes are at a highest risk of anemia (3)
females
distance runners
vegetarian athletes
excess iron reduces which absorption ?
Zn and Cu
why should you usually not be concerned about having iron in diet ?
because energy intake is correlated with iron
what percentage of iron goes to storage
25 %
does anemia change VO2max ?
yes, decreases it
what is B12 called
cobalamin
what is the structure of B12 ?
corrinoid compound: ring structure with cobalt in the middle
what is the function of B12 ? (4)
DNA synthesis
myelin sheath
FA oxidation
convert homocysteine to methionine to decrease CVD risk
which two vitamins are active in DNA synthesis ?
folate and B12
how does B12 decrease CVD risk
convert homocysteine to methionine
why does it take a while to spot a B12 deficiency?
because liver stores are food for 2 years, so symptoms may not appear to up to 12 years
what population is mostly at risk of B12 deficiency ?
vegan
old
what are the two food sources of vitamin B12 ?
animal products
fortified foods
what is the function of folate ?
DNA synthesis and cell division
eg prevents neural tube defects during pregnancy and also aids in maturation of RBC
increase of folate may mask which deficiency
B12
which foods are a food source of folate ?
chicken, grains
what are the 4 micronutrients of concern (1 vitamin and 3 minerals) for vegetarians
B12
iron, calcium, zinc
are megadoses helpful ?
no evidence that it is helpful
which 3 athletes need monitoring and for what ?
young athletes in sports that need low body weight (Ca and Fe)
amenorrheic females (Ca)
train and compete in hot environments (losses in sweat of Fe, Zn, Mg)
which liquid should one avoid if you want to get more iron in you
tea
what is the main reason for micronutrient insufficiency ?
poor diet (insufficient kcal)
what is another word for vit C
ascorbic acid
should amenorrheic females take Ca supplements ?
yes
