Micronutrients Flashcards
why do we need micronutrients? / role of micronutrients?
micronutrients act as:
- *1. co-factors:** compound required for a proteins biologal activity
- *2.** co-enzymes: help enzymes catalyse a reaction
- *3. antioxidants:** inhibits the oxidation of other molecules. counteracts free radicals
- *4. control of gene expression**
- *5. structure:** e.g phosopholipids causes complexes with Mg & Ca
what are the different types of sources that free radicals can be derived from? (2)
what can they have an adverse reaction on?
endogenous sources: mito, peroxisomes, ER
exogenous sources: pollution, alcohol, tobacco, paracetemol
adverse reactions on: nucleic acids, lipids & proteins :(
how does an antioxidant work?
e.g.?s (5)
antioxidant:
- free radicals cause chain reaction of oxidation causing damage
- antioxidants: neutralise free radicals by ‘lending; an electron to stabilise damaged atoms
examples:
vitamin A, C, E & copper, zinc & selenium
which micronutrient is important in imprinting home to the gut mucosa from peyers patches?
how does it occur (2)
vitmain A: precursor for retinoic acid !
- gut dendritic cells use retinoic acid to inform the niave T cells
- causes niave T cells to change transcription to express CCR9 & a4B& to do gut honing
which population are micronutrients most important in?
WHY? (3)
most important in paediatric population: (body growth & development; energy supply; healthy infants have 3x energy per kg body weights than adults)
which micronutrient helps to improve childrens learning ability and cognitive development? WHY? (1)
iron helps to improve childrens learning ability and cognitive development: Fe helps Hb to carry oxygen to neurons in brain
if someone is malnourished, what is going to be impaired? (7)
- impaired wound healing
- reduced fertlitliy
- impaired immune response - predisposes to infection
- reduced muscle strength
- depression
- increased risk to post-op complications
- inactivity - pressure sorees
what are vegans likely to be deficient in? (2)
- *vitamin D: (**oily fish, dairy products)
- *vitamin B12 (**meat and dairy food)
what are fat-soluble vitamins (4?)
which are water-soluble vitamins? (2)
which can be stored / which normally excreted? what does this mean as a consequence?
fat soluble: A D E K -> can be stored in liver (but can be toxic in XS)
- absorbed with fats (readily absorb in micelles & chylomicrons)
water soluble: B & C -> normally excreted
why is commensal bacteria gut overgrowth clinically significant regarding vitamins?
commensal bacteria: providers AND consumers of B vitamins** & **vitamin K.
overgrowth: likely to have B12 deficiency & high B9
vitamin deficiency in deveoloped countries is likely from two overarching categories. what are they?
**decreased intake
decreased absorption**
what are main causes of vitamin deficieny in developed countries are
- *decreased intake:**
- alcohol:
- vegans:
- elderly w. poor diet:
- anorexia:
- *decreased absorption:**
- malabsorbative state e.g. coeliac disease:
- ileal diease:
- liver & biliary tract disease:
- intestinal bacterial overgrowth:
- oral antibiotics:
what are they likely to be deficient in?
- *decreased intake:**
- alcohol: B vitamins
- vegans: Vit D & Vit B12
- elderly w. poor diet: Vit D & folate
- anorexia: folate
- *decreased absorption:**
- malabsorbative state e.g. coeliac disease: folate (B9)
- ileal diease: only B12
- liver & biliary tract disease: fat soluble vitamins (bc bile helps absorb fat !)
- intestinal bacterial overgrowth: b12
- oral antibiotics: vit K
what are the clinical features of deficiences in
vitamin A
vitamin D
vitamin E
vitamin K
(fat soluble vitamins)
vitamin A: eyes -> xeropthalmia (Xerophthalmia refers to the spectrum of ocular disease caused by severe Vitamin A deficiency (VAD))
vitamin D: rickets (in adults = osteomalacia)
vitamin E: peripheral neuropathy
vitamin K: coagulopathy
what are the clinical features of deficiences in
- vit c
- B1
- B2
- B3
- B4
- B6
- B12
- folate?
- vit c: scurvy
- B1: beri beri
- B2: angular stomatitis
- B3: pellagra
- B4: anemia
- B6: anemia
- B12: anemia (but also lots of neurological disorders)
- folate: anemia
trace element deficiencies?
calcium?
phosphorous?
iron?
selenium
zinc
copper
calcium: bone problems ! osteoporosis, muscle spasms
phosphorous: bone pain, pseudofractures
iron: anemia, muscle problems
selenium: cardiomyopathy
zinc: growth retardation, congenital deformation
copper: growth retardation