MCP Lecture 5 Flashcards
What type of nutrient are vitamins and minerals referred to as? What does a deficiency in a vitamin cause?
- micronutrients
- loss of enzyme activity (bc they act as coenzymes)
What is DRI? RDA?
DRI: dietary reference intakes
RDA: recommended daily allowance (which varies for different populations)
How do vitamin deficiencies arise?
- poor nutrition
- increased demand
- problem with absorption
- interactions with medications
What are the classifications of vitamins, and which vitamins fall in the classifications?
lipid soluble: A, D, K, E
water soluble: B, C
Which vitamins are less likely to be toxic and why?
B and C because they are water soluble are excreted efficiently (lipid soluble can be stored efficiently so deficiencies don’t arise as easily)
Vitamin A: function, deficiency, susceptible groups
Function: visual cycle (rhodopsin and cone cofactor), synthesis of certain glycoprotein and mucopolysaccharides, retinoic acid (hormone), antioxidant
Deficiency: night blindness, xerophthaliam, follicular hyperkeratosis, anemia, poor growth (children)
Susceptible groups: poor, malnourished, premies
Sources of Vitamin A
retinol (vit A): egg yolks, liver, butter, whole milk (animal sources)
carotenoids (precursor vit A): plant sources (pro vitamins)
When is Vitamin A toxic? What are the symptoms?
When it accumulates in the liver - nausea, diarrhea, bone pain, scaly skin, orange cast to skin
What is follicular hyperkeratosis?
vitamin A deficiency - skin in permanent goosebumps
What is xerophthalmia?
vitamin A deficiency - overgrowth of cornea (extreme dryness and thickening of the conjunctiva)
Vitamin D: function, deficiency, susceptible groups
function: maintaining bone, calcium homeostasis, acts as hormone
deficiency: rickets, osteomalacia, increased susceptibility to breast and other cancers
susceptible: poor, elderly, alcoholics
How is active Vitamin D synthesized?
skin (sunlight) - dietary sources = saltwater fish
liver (hydroxylation)
kidney (hydroxylation)
converted to D3 = calcitriol
Vitamin K: function, deficiency, susceptible groups
function: localization of enzymes required for blood Klotting (helps catalyze addition of gama-carboxyglutamate to clotting enzymes)
deficiency: easy bruising, bleeding, hemorrhage
susceptible: newborn infants and long term antibiotics
What causes deficiency in Vitamin K?
lack of intestinal bacteria that makes it (why its newborns and long term antibiotics) - shot now given at birth
Vitamin E: function, deficiency, susceptible groups
function: ANTIOXIDANT (protect membranes, prevent oxidation of LDL)
deficiency: cardiovascular disease and neurological symptoms
susceptible: prolonged defects in absorption, genetic defects
What are dietary sources of vitamin E?
OILS
Vitamin C: function, deficiency, susceptible groups
function: cofactor for oxidases involved in COLLAGEN formation, synthesis of steroids, absorption of iron, antioxidant
deficiency: mild bruising and immunocompromise
severe: SCURVY (decreased wound healing, osteoporosis, hemorrhage and anemia, fatigue)
susceptible groups: pirates, people with poor diet, smokers
What is the major function of vitamin C?
hydroxylation of proline and lysine - important in collagen synthesis
What are the early and later signs of scurvy?
early: corkscrew hairs and pinpoint hemorrhages
later: severe periodontal disease
What are the two subcategories of B Complex vitamins? What are the vitamins in the groups?
Energy releasing: B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin)
Hematopoietic: B9 (folate), B12 (cobalamin)
What are common effects of deficiencies in energy-releasing B vitamins?
first show up in rapidly growing tissues: dermatitis, swollen red tongue (glossitis), GI (diarrhea)
also seen in nervous system bc energy demand: peripheral neuropathy (tingling of extremities), depression, confusion, lack of coordination, malaise)
Thiamine: number, function, deficiency, susceptible groups
number: B1
function: cofactor for several enzymes in cellular energy metabolism, critical in nervous system
deficiency: mild - GI symptoms, depression, fatigue
moderate - wernicke korsakoff syndrome
severe - beriberi
What is thiamine a precursor of?
TPP - coenzyme for critical metabolic enzymes
thiamine not stored in body - deficiency can be quick
What is Wernicke- Korsakoff syndrome?
moderate/severe thiamine deficiency - seen in chronic alcoholics
-mental disturbance (like they’re drunk) - unsteady gait, uncoordinated eye movements
