Fat Soluble Vit-- Review with handout

Question 1

Fat soluble vitamin

Answer 1

Vit ADEK

Question 2

Water soluble vs fat soluble

Answer 2

water soluble:
Not stored (except B12)
Highly absorbed from diet
Excreted in urine
Low toxicity

Fat Soluble
Accumulate in “stores”
Require dietary fat absorption
\+/- blood transport system
Potential toxicity with excess intake

Question 3

Micronutrient Deficiency Risk

Answer 3

Inadequate or monotonous diet

Increased nutrient requirements

Increased metabolic demands

Malabsorption

Interactions w/ pharmaceuticals

Question 4

Vit A Function

Answer 4

Photochemical for vision
retinal signaling
Maintenance of conjunctiva and cornea

Question 5

Vit A Sources

Answer 5

1. Preformed retinyl palmitate from animal sources
   Liver, dairy, egg yolk, fish oil
2. Precursor Beta-carotene
   Deep yellow and green vegetables
   Spinach, carrots, broccoli, pumpkin

Question 6

Vit A Deficiency

Answer 6

EYES: xerophthalmia (corneal dryness) Bitot’s Spots, night blindness leading to total blindness

EPITHELIUM:
linings flat, dry, and keratinized

Immune Impairment:
Dysregulation
Effect depends on infectious agent
Treatment of Deficiency decreases all cause child mortality 23-34% in developing world
Vit A treatment with measles reduces morbidity and mortality
including in US when retinol level is low

Question 7

Risk of Vit A Deficiency

Answer 7

Low Vit A intake:

• Diet poor in colored vegs, meat/dairy
  e. g. autistic child with severely restricted diet
• Protein Energy Malnutrition
• Very Low fat intake (

Question 8

Vit A Toxicity

Answer 8

NOT from precursor beta carotene
-ONLY with preformed Vit A (retinyl palmitate) eg cod liver oil

Sx:
Vomiting, increased ICP, headache
bone pain, osteopenia/porosis
liver damage hepatitis–>fibrosis–> failure
-death
-birth defects e.g. isotretinoin (Accutane, an acne medication)

Question 9

Vit A Lab Testing

Answer 9

Serum Retinol level
-Remains normal until liver stores exhausted
-Decreased with inflammation:
Negative Acute Phase Reactant

Question 10

Vit D Function

Answer 10

Hormone
-Plasma membrane and nuclear receptors in a range of tissues

Maintains intra/extracellular Ca++ levels
-Mediates intestinal absorption Ca and Phos, renal reabsorption, and mobilization from bone

Immune function –

• Innate: helps with antimicrobial peptide generation (cathelicidin and defensins) in macrophages
• Adaptive: modulation of cytokines

Regulates cell growth and differentiation

Question 11

Vit D Sources

Answer 11

Conversion in skin
UVB light–> Dehydrocholesterol–> Cholecalciferol D3 in skin

Dietary:
Fish liver oils, fatty fish, egg yolks
Fortified milk and formula

Sources
Plant algae, yeast+UV–> D2 ergocalciferol
Animal D3 cholecalciferol –> more potent? larger AUC than D2, similar peak plasma 25OH
(D2 or D3 can be effectively used as a supplement)

Question 12

Vit D Metabolism

Answer 12

Absorption – chylomicrons
Requires fat absorption

Hydroxylation
D2 or D3 +OH in liver
25 OH Vit D –level reflects body stores
25 OH Vit D hydroxylated in kidney to active form 1,25 OH Vit D (Calcitriol)

Lab test looks at 25 OH Vit D

Question 13

Vit D Deficiency

Answer 13

Definition IOM Standard:
Deficiency 25OH Vit D less than 20 ng/mL
Insufficient 20-30
Sufficient: >30

Classical Syndrome
Childhood rickets -

Question 14

Emerging Associations w/ Vit D Def

Answer 14

-mostly epidemiologic/in vitro
-few RCTs
Autoimmune Disorders (e.g. MS)
Neuromuscular function
Cardiovascular Disease
Cancer incidence
Overall Mortality

-Adequate evidence not yet found

Question 15

Risk for Vit D deficiency

Answer 15

Low Sun exposure (NE winter)
Dark Pigmentation
Low dietary intake
Fat Malabsorption
Breastfed Infant --> supplement
Obesity: Fat sequestration, sedentary
Liver or Renal Disease (X-OH, can't perform hydroxylation steps): Need Calcitriol Rx supplementation

Question 16

Vit D Supplementation

Answer 16

Breastfed Infants
400IU D3 per day by 2 months
Until 500ml/d (>16oz) formula or milk
Or formula fed taking 70 years
Some experts have recommended higher dosing 800-1000IU per day
To Maintain 25OH D >30ng/mL, but evidence lacking

Question 17

Vit D Toxicity

Answer 17

Findings
Hypercalcemia
Vomiting, seizures, nephrocalcinosis, vascular and soft tissue calcinosis

Risk
Sarcoidosis (granulomas throughout body activate D)
>10,000 IU/d for wks in child or during pregnancy
50-100,000 IU daily in adult >3wks

Question 18

Vit E Function and Sources

Answer 18

Function: antioxidant, scavenges free radicals, stabilizes cell membranes

Sources: Polyunsaturated fat rich vegetable oils (e.g. sunflower), corn, nuts, wheat germ

Question 19

Vit E Deficiency

Answer 19

Neurologic Degeneration IRREVERSIBLE
Loss of reflexes (DTRs)
Loss of coordination
Loss of vibration and position sense
Spinocerebellar ataxia
Neuropathy
Ophthalmoplegia

Hemolytic Anemia

Risk: malnourishment, prematurity, fat malbsorption /short gut

Question 20

Vit E Toxicity

Answer 20

Relatively Low
Coagulopathy
-Very large doses inhibit Vit K dependent clotting factors

Literature does not support megadoses for CVD/cancer protection

Question 21

Vit K Function and Sources

Answer 21

Function – carboxylation of clotting factor proteins (II prothrombin, VII, IX, X)

Sources – leafy greens, brocolli, fruits, seeds, beef liver
Synthesis by Intestinal Bacteria

Question 22

Vit K Deficiency

Answer 22

Findings:
-prolonged coagulation time
-Hemorrhagic disease of the newborn:
Purpura, GI bleeds, CNS bleeds

Risk:
Newborns – poor placental transport (large molecule)
2-12 wks breastfed untreated
Fat Malabsorption
Chronic Antibiotics

Prevention:

• all Newborns 0.5-1.0mg IM once
• Adequate oral dosing has not been defined

Question 23

Summary of Deficiency findings

Answer 23

A:
finding:Eyes, epithelium, infections
Risk: Poor or extreme low fat diet

D:
Finding:Rickets, Osteopenia/malacia, possibly more?
Risk: Low sun, dark pigment, obesity, breastfeeding, liver/kidney dz

E:

finding: Neurologic, anemia
risk: prematurity

K:
finding: impaired clotting
Risk: newborn, abx, poor diet