Micronutrients Flashcards
what are micronutrients made out of
- vitamins (organic)
- trace elements (inorganic)
what are micronutrients
these are essential compounds that are required in the diet at very small amounts
Role of micronutrients
Cofactor coenzymes Antioxidant genetic control structural components
what does a cofactor do
- non-protein chemical compound or metallic ion required for a protein’s biological activity to happen.
- Iron / Zinc
what does coenzymes do
- Small non-protein organic molecule
- Cannot catalyze a reaction by themselves but they help enzymes to do so.
- example includes Thiamine pyrophosphate (TPP)
what do antioxidants do
- they inhibit the oxidation of other molecules
- examples include beta-carotene and vitamin C
what does genetic control do
substances such as vitamin A and D control gene expression
what do they do as a structural component
- Phospholipids form complexes with both Mg2+ and Ca2+.
- These complexes are parts of membranes in the cell
what do micronutrients do in adults
- maintain homeostasis
what do micronutrients do in children
- they are more important in children
- they are used as an energy supply
- they are used as body growth and development
- this is because they have a higher metabolism than adult
Supply of micronutrients has
short and long term health implications
what food can you get in vitamin D
oily fish
diary products
orange juice
where can you get B12
meet and dairy food
if you are vegan what vitamins will you be lacking
- Vitamin D
- vitamin B12
- therefore you need to take supplements
what gives us the amount of vitamins that we should have
- recommended dietary allowance
- limits are defined for deficiency or toxicity
name some fat soluble vitamins
A D E K
name some water soluble vitamins
B, Folate (B9),Biotin (B7), C
what is the difference between fat soluble vitamins and water soluble vitamins
Fat soluble
- these can be stored in the body
- they are toxic when they are in excess
water soluble
- they are not stored in the body
- they often act as coenzymes
- No toxicity as it is excreted in the urine
- excess is excreted in the urine
where do fat soluble and water soluble vitamins go
fat soluble - lymph fluid
water soluble - portal vein
if you have alcohol dependency what vitamin do you have deficiency in
Chiefly B vitamins (Vit B1)
if you have small bowel disease what vitamin do you have deficiency in
Chiefly Folate (Vit B9)
if you are elderly with a poor diet what vitamin do you have deficiency in
Chiefly Vit D (if no sunshine); Folate
if you have anorexia what vitamin do you have deficiency in
chiefly folate
what are the causes of vitamin deficiency in developed countries
- decreased intake
- decreased absorption
- long term enteral or paranteral nutrition
- drugs antagonists (methotrexate interfering with folate metabolism)
if you have Ileal disease what vitamin are you lacking
only vitamin B12
if you have liver and billiary tract disease what vitamin are you lacking
Fat soluble vitamins
if you have Intestinal bacterial overgrowth what vitamin are you lacking
vitamin B12
if you have oral antibiotics what vitamin are you lacking
vitamin K
if you have renal disease what vitamin defincey to you have
- vitamin D
vitamin A
- Contributing factors to deficiency
- Clinical features
Contributing factors to defienciy:
- Infection, measles, protein-energy malnutrition
clinical features:
Xerophthalmia,
vitamin D
- Contributing factors to deficiency
- Clinical features
Contributing factors in deficiency:
- Aging, lack of sunlight exposure
Clinical features:
- Rickets; osteomalacia
Vitamin E
- Contributing factors to deficiency
- Clinical features
Contributing factors in deficiency:
Antibiotic use
Clinical features:
Peripheral neuropathy, spinocerebellar ataxia, skeletal
muscle atrophy, retinopathy
Vitamin K
- Contributing factors to deficiency
- Clinical features
Contributing factors in deficiency:
Antibiotic use
Clinical features:
Coagulopathy
Vitamin C
- Contributing factors to deficiency
- Clinical features
Contributing factors in deficiency:
smoking
Clinical features:
scurvy
B1
- Contributing factors to deficiency
- Clinical features
Contributing factors in deficiency:
Concommittant Vitamin B6, B12 & folate deficiency
Clinical features:
Beri beri
B2
- Contributing factors to deficiency
- Clinical features
Contributing factors in deficiency:
Malabsorption
Clinical features:
Magenta tongue, angular stomatitis, seborrhea,cheilosis
B3
- Contributing factors to deficiency
- Clinical features
Contributing factors in deficiency:
Vitamin B6 deficiency, riboflavin deficiency
Clinical features:
Pellagra
B6
- Contributing factors to deficiency
- Clinical features
Contributing factors in deficiency:
Isoniazid use
Clinical features:
- neuropathy and anaemia
B12
- Contributing factors to deficiency
- Clinical features
Contributing factors in deficiency:
Gastric atrophy (pernicious anemia),
terminal ileal disease, strict
vegetarianism
Clinical features:
Anaemia,
Folate
- Contributing factors to deficiency
- Clinical features
Contributing factors in deficiency:
Sulfasalazine, pyrimethamine, triamterene
Clinical features:
Anaemia
Calcium
- Function
- deficiency
Function:
Mechanical stability of the skeleton, neuromuscular activity, signal transduction
Deficiency:
- osteoporosis
- parenthesis
- muscle spams
Phosphorus
- Function
- deficiency
Function:
Component of structural proteins, enzymes, transcription factors, ATP and nucleic acids
Deficiency:
Bone pain, pseudofractures, and proximal muscle weakness or, rickets and short stature in children neurological manifestations
Iron
- Function
- deficiency
Function:
Part of the heme protein and enzymes
Deficiency:
Anemia
selenium
- Function
- deficiency
Function:
Component of glutathione peroxidase and deiodinase enzymes
Deficiency:
cardiomyopathy
zinc
- Function
- deficiency
Function:
Synthesis and stabilization of proteins, DNA, and RNA ; normal spermatogenesis, fetal growth, and embryonic development
Deficiency:
Growth retardation, alopecia, dermatitis, diarrhoea, congenital malformations
copper
- Function
- deficiency
Function:
Part of numerous enzymes for iron metabolism; melanin, elastin and collagen synthesis; and central nervous system function
Deficiency:
growth retardation
how many deaths does malnutrition cause
1/3 of child deaths worldwide
what is kwashiorkor
- effects babies and toddlers
- caused by a lack of protein
- involved micronutiernta and antioxidant deficiencies
what happens in marasmus
- servere malnutrition
- muscle wasting/protein loss
why is nutrient important
- Impaired wound healing
- Impaired immune response, predisposing to infection
- Reduced muscle strength – delayed recovery from chest infection or weaning off ventilator, impaired cardiac function, reduced mobility
- Inactivity – pressure sores, thromboembolism
- Increased risk of postoperative complications
- Depression and self-neglect
what does iron defiency lead to
Anaemia- ability to effect oxygen delivery to the body, lethargy & constitutional disturbance
why is Iron important
- Oxygen transport within haemoglobin
- Myoglobin function in skeletal muscle
where is iron absorbed
- in the upper small bowel
how is iron transported in serum
- with transferrin
how is iron stored
Iron is stored in liver and bone marrow as ferritin
what prevents too much iron
Be aware of haem chelaters (used to prevent Iron overload / and prevent oxidative damage in patients)
what happens if you have a deficiency in iron
Microcytic anaemia Lethargy & fatigue Adults Cognitive impairment Children Exacerbation of inflammatory states
what happens if you have excess in iron
Haemochromatosis Lethargy & fatigue Abdominal & joint pain Reduced libido Bronzing of skin Diabetes Cirrhosis Cardiomyopathy
what disorders does vitamin D cause
osteomalacia and rickets
what is D3 and why it is special
Cholecalciferol (D3)
- special as we can make it artificially by adding UV light to D2
How can you make vitamin D
sunlight
Caucasians
20-30 minutes of sunlight ≈ 2,000 iU Vitamin D
Two or three exposures a week during summer
Non-causcasian
Require 2-10 times the exposure- melanin acts as a barrier
what lifestyle factors contribute to vitamin D deficiency
Obesity Smoking (and Betel) Alcohol Exercise Exclusive breast feeding >6/12
what disease factors lead to vitamin D deficiency
Reduced skin synthesis Decreased bioavailability Drug-related Increased excretion Impaired hydroxylation Acquired
what is rickets
- this is when you have growth retardation
- this causes the expansion of the growth plate
- it happens in children prior to epiphyseal fusion
what is osteomalacia
- this is when you have reduced bone strength
what are symptoms of osteomalacia
Increase in bone fracture Bone pain Bending of bones Muscle weakness Waddling gait
what does B1 (thiamine) deficiency lead to
Wernicke’s Encephalopathy &
Korsakoff’s Psychosis
Where is B1 absorbed
jejunum
what is B1 involved in
Involved in glycolysis and Krebs cycle - cannot be able to generate energy and ATP, start producing lactic acid and anaerobic respiration instead
Involved in BCAA metabolism
Involved in pentose phosphate cycle metabolism
where is vitamin B1 seen
Most commonly seen in malignancy and alcoholism
Anorexia & weight loss
what are the symptoms of vitamin B1
Cognitive impairment
Muscle weakness
What are the two types of BeriBeri
dry and wet and shoshin
describe dry beri beri
- effects peripheral neuropathy
- effects motor and sensory
describe what happens in wet beri beri
Cardiac - Enlarged heart - Tachycardia - High-output CCF - Peripheral oedema Neurological - Peripheral neuritis
describes what happens in shoshin Beriberi
Fulminant cardiac failure
Lactic acidosis
what are the symptoms of Wernicke’s encephalopathy
Horizontal nystagmus (involuntary, rapid and repetitive movement of the eyes) Ophthalmoplegia (paralysis or weakness of the eye) Cerebellar ataxia (inflamed cerebellum)
what are the symptoms of Korsakoff syndrome
- Korsakoff syndrome
Mental impairment (additional loss of memory and a confabulatory psychosis). - It is irreversible!
what does vitamin B3 definitely lead to
pellagra
where is vitamin B3 absorbed
jejunum
what happens to excess B3
It is excreted in the urine
what are the 2 chemical forms of vitamin B3
nicotinic acid
nicotinamide
describe the structure of vitamin B3
- Form two pyridine nucleotides (NAD and NADP) which act as hydrogen acceptors in many oxidative reactions
- their reduced forms (NADH and NADPH) act as hydrogen donors in reductive reactions.
when would you get vitamin B3 deficiency
Vegetarian diets (corn based), alcoholism, other vitamin deficiency states
what diseases does vitamin B3 lead to
- Hartnups diseae
- carcinoid syndrome
- isoniazid use - for TB treatment
what is hartnups disease
Congenital defects of intestinal and kidney absorption of tryptophan
what is carcinoid syndrome
Increased conversion of tryptophan to Serotonin
what happens if the diet is deficient in niacin
If the diet is deficient in niacin, your body can manufacture it from tryptophan
what are early symptoms of pellagra
Loss of appetite Generalized weakness Irritability Abdominal pain Vomiting Bright-red glossitis
what are late symptoms of pellagra
“Casal’s necklace” Vaginitis Oesophagitis Diarrhoea Depression Seizures The four D’s: dermatitis, diarrhoea, dementia , death
what happens with niacin toxicity
Flushing has been observed at therapeutic dose of niacin (hypertrigliceridemia)
Glucose intolerance, macular oedema, and macular cysts
what happens in vitamin B9 folate deficiency
Neural tube defects in fetus
what happens in vitamin B12 deficiency
Anaemia, GI & neurological disturbance
how much of vitamin B12 is absorbed or excreted
40% absorbed, 60% excreted in urine or bile
what is vitamin B12 used for
Cofactor for methionine synthase and methylmalonyl–coenzyme A (CoA) synthase
Available in many forms
Cyanocobalamin used therapeutically
what causes vitamin B12 deficiency
Disorders of terminal ileum Defective release of cobalamin from food Inadequate production of IF Transcobalamin II deficiency (rare) Congenital enzyme defects (rare)
