Vitamins Flashcards
RDI means
Recommended Daily Intake.
Average amount of nutrient considered to be sufficient to meet the requirements of 97–98% of healthy individuals in every demographic per day
This is a non-specific population based number. ‘two standard deviations away from the mean’
EAR
Estimated Average Requirement. Expected to satisfy the needs of 50% of the people in that age group. Halfway (peak) of population.
Lies in the marginal deficiency zone.
AI
Average Intake. Used when you have limited/inconsistent data and RDI and EAR.
NRV
Nutrient Reference Values. Extremely complicated
Naive View: Danger > RDI > safety
Accurate View: danger of deficiency > marginal > safety> RDI/AI > safety > marginal > danger of toxicity
How do you find peoples needed nutrient intakes, why is this hard?
You need to completely remove it, in doing so often removing entire food group/s, and then gradually increase until optimal health
Above RDI/AI
margin of safety > margin of toxicity > danger of toxicity
Below RDI/AI
margin of safety > margin of deficiency > danger of deficiency
List the water soluble Vitamins..
" I want to B by the C to see Fish Bitch" B vitamins Vitamin C Folate Biotin
List the fat-soluble vitamins
“DrAKE”
vitamins D, A, K, E
Water soluble Absorption: Transport: Storage: Excretion: Toxicity Requirements:
Absorption: directly into blood
Transport: freely in blood
Storage: circulate in water-filled areas
Excretion: via kidneys (detect excess) in urine
Toxicity: possible with supplements
Requirements: Frequent doses every 1-3 days
Fat Soluble Absorption: Transport: Storage: Excretion: Toxicity: Requirements:
Absorption: > lymph > blood
Transport: often require protein carriers
Storage: stored in cells associated with fat
Excretion: tends to remain in storage
Toxicity; likely to reach, especially with supplements
Requirements: rarely, months
Factors affecting bioavailability (think broccoli)
Health status Previous nutrient intake Food/prep (boiling loses nutrients) Other foods consumed simultaneously source: synthetic/natural Effectiveness of digestion/transit time
B vitamins
"The Really Nice Pitapit Comes w Falafel" Thiomin 1 Riboflavin 2 Niacin 3 Pyridaxine 6 Cobalamin 12 Folate 19 Pantothenic acid 5 Biotin 7
What will a deficiency of B vitamins affect?
A large number of systems, energy production and the ability to produce specific aa.
Thiamine (B1) is involved in?
Glycolysis: pyruvate»»> actyl coA (via TPP)
Conversion of keto acids: Some aa»_space; some aa (via TPP)
Specifically what will a deficiency of thiamine lead to. What is this called?
- decreased energy production and specific aa
-decreased hormone production
Wet Beriberi and Dry Beriberi
Wet Beriberi Symptoms
due to thiamine deficiency. ‘wet’ (edema)
- swelling/ oedema
- tachycardia
- lung congestion
- congestive heart failure
CVD
You can press hole into skin
Dry Beriberi Symptoms
pain/tingling (dermititis)
Loss of sensation of hands and feet (peripheral neuropathy)
muscle wasting (loss of lower extremity function)
brain damage/ death
NEUROLOGICAL DISEASE
Where is beriberi endemic? Apart from wet/dry what other beriberi exists
in countries that use rice as a staple food source, and the rice is refined (husk removed), and you lose the thiamine.
Also in prisons
Infant Beriberi exists
In the western world, what is the main cause of thiamine deficiency. What does this lead to?
Alcoholism. Because its involved in removal of alcohol from liver and carb metabolism.
Wernicke-encephalopathy: alcohol related brain-damage. Language, walking issues, unusual eye movement.
Korsakoff Syndrome: amnesia, inability to learn, confabulation
How does folate (B9) occur. How is it absorbed?
Naturally as polyglutamate
fortified foods and supplements as monoglutamate
in the intestines, digestion breaks glutamates off and adds a methyl group. Folate absorbed and delivered to ce;;s/
Folate deficiency and B12
will decrease
Folate deficiency causes
1) Megoblastic anaemia- large, unorganised, disrupted shape
2) Neural Tube Defects- mainly spina bifida. CNS developed early ~5-8 weeks.
mothers need folate EARLY (4wk before, 12wks after)
3) Elevated risk of cancer and CVD
Spina Bifida
inability of spinal cord to completely close off. Spinal cord on the outside of the body. Leads to paralysis of lower limbs
Causes of low folate
1) Low dietary intake (green leafy)
2) Low intestinal absorption
3) High alcohol intake > decreased absorption
4) Pregnancy = increased folate required for GROWTH
How much/why do women need folate during pregnancy? Why does this often not occur?
800 micrograms 4 wks prior
5000micrograms 12 wks post
due to an increased growth. To avoid NTD
NZ= 12-14 per 10,000
countries w mandatory fortification= 7-9 per 10,000
BUT women often don’t know they’re pregnant! (50% unplanned pregnancies)
% of women using folate for planned vs unplanned pregnancies
Unplanned: 9%
Planned: 58%
How does vitamin A and Beta-carotene aid vision
Retinyl ester (animal) > retinol Beta-carotene (plant) > retinal
Retinol retinal > retinoic acid
1) light enters eye, hits pigments at back of eye
2) Rhodopsin absorb (opsin + cis-retinal)
3) cis-retinal > trans-retinal which triggers a nerve impulse to brain, we see light
Night vision if impaired with a deficiency of
Vitamin A
skin bumps, redness caused by vitamin A deficiency is called?
Deficiency syndrome keratinisation
Vitamin a and the mucosal membrane?
Maintain healthy cells, without, the normal structure and function of these mucosal cells is impaired.
Beta-carotene is?
Precursor of Vitamin A, changed to vitamin A in the body (retinol)
Vitamin A toxicity can occur by? Can this be reversed?
Beta-carotene: overconsumption, inefficient conversion (yellow skin)
Can be reversed as BC is water soluble
Retinol: overconsumption of supplements (liver damage)
Types of vitamin D
Calciferol
1,25 dihydroxyvitamin D (active hydroxylated)
Vitamin D3 (animal)
Vitamin D2 (plant)
Precursor of vitamin D
bodies own cholesterol, precursor 7-dehydrocholesterol made in liver
How do we get vitamin D from ‘sunlight’
7-dehydrocholesterol > (UV) > pre-vitamin D3 (+foods) > inactive vitamin D3 > 25-hydoxyvitamin D3 (liver) > 1, 25 dehydroxyvitamin D3 (kidneys
Main food sources of vitamin D? RDI?
RDI= 400units/day
cod liver oil
salmon
sardines
Function of Vitamin D?
important for Calcium > muscle and bone growth/development
Regu;ates BP and insulin
Regulates cell growth and immune function
Vitamin D deficiency results in…
Who is most at risk, and when
1) Rickets: children, bowlegging due to poor bone formation around weight-bearing time
2) osteomalacia: adults
Risk for: recent migrantsm darker skin, religions that cover skin
also during winter months
Who needs Vitamin/ mineral supplements?
Poor nutrient intake (elderly, dieters, adolescents, vegetarians)
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Increased nutrient requirements (children, pregnancy/ lactation)
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Increased metabolic demands (surgery/trauma/fracture)
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Maldigestion or malabsorption (liver disease, GI, diarrhea)
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Drug-nutrient interactions (prednisone/vit D, diuretics/K,Mg)
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Medical treatment interactions (chemo/radiation)
