2 - Micronutrients2 Flashcards
1
Q
Definition of micronutrients
A
Essential compounds required in small amounts in diet
vitamins + trace elements
2
Q
Dietary sources of vitamins
- A,D,E,K,C,B1,B2,B3,B6,Biotin, B12, Folate
A
A - liver, fish D - oily fish, dairy E - oils, nuts, soybean K - dark green, prunes C - Fruits, green veg B1 - Yeast, whole grains B2 - Dairy products, bread and cereal B3 - Beans, milk B6 - Tuna, poultry Biotin - Liver, soy beans B12 - Meat and dairy Folate - Fruits and veg
3
Q
Uses of micronutrients
A
Cofactor Coenzymes Genetic control Anti oxidant Structure
4
Q
Functions of micronutrients
A
Maintains homeostasis
Energy supply, growth and development in children
5
Q
How can preventing iron deficiency benefit children
A
Improves cognitive ability
6
Q
Benefit of folic acid
A
Prevents spina bifida and macrocytic anaemia
7
Q
What are the intake requirements for micronutrients
A
Intake to meet req for 98% of population
8
Q
Fat soluble vitamins
A
ADEK
9
Q
Features of fat soluble vitamins
A
Can be stored
Occasionally toxic
10
Q
How are fat soluble vitamins transported
A
Converted into micelle
Becomes chylomicrons in the intestine
Goes into the lymph fluid
11
Q
Water soluble vitamins
A
B, Biotin, Folic and C
12
Q
Features of water soluble vitamins
A
Not stored
Excess excreted
Acts as co enzymes
Goes into the portal vein
13
Q
What causes deficiency of fat soluble vitamins
A
Fat malabsorption
Alcoholism
Liver disease
14
Q
Vitamin A deficiency
A
Xerophthalmia, night blindness, bitot spots, follicular hyperkeratosis, impaired embryonic development
15
Q
Causes of vitamin A deficiency
A
Infection, measles, protein-energy malnutrition
16
Q
Vitamin D deficiency
A
Rickets, osteomalacia
17
Q
Causes of vitamin D deficiency
A
Ageing, lack of sunlight exposure
18
Q
Vitamin E deficiency
A
Peripheral neuropathy, spinocerebellar ataxia, retinopathy, skeletal muscle atrophy
19
Q
Cause of vitamin E + K def
A
Antibiotic use
20
Q
Vitamin K deficiency
A
Coagulopathy
21
Q
Causes of water soluble vitamin deficiency
A
Alcoholism, any maladaptive state, drugs
22
Q
Vitamin C deficiency
A
Scurvy
23
Q
Cause of vitamin C deficiency
A
Smoking
24
Q
B1 deficiency
A
Beri Beri
25
B2 deficiency
Angular stomatitis
26
B3 deficiency
Pellagra
27
B6 deficiency
Neuropathy
Anaemia
Glossitis
caused by isoniazid use
28
B12 deficiency
Anaemia, neurological disorders
| caused by gastric atrophy
29
Folate deficiency
Anaemia, atrophic glossitis, depression
30
Cause of vitamin deficiency in developed countries
```
Decreased intake
Decreased absorption
Renal disease
long term enteral and parental feeding
Drugs e.g methotrexate and folate
```
31
Alcoholism
B1 deficiency
32
Small bowel disease
Folate and B9 deficiency
33
Vegans
Vitamin D and B12 deficiency
34
Elderly with poor diet
Vitamin D and folate def
35
Anorexia
Folate def
36
Ileal disease + resection
Vitamin B12 def
37
Liver and biliary disease
Fat soluble vitamins
38
Intestinal bacterial overgrowth
Vitamin B12 def
39
Antibiotics
Vitamin K def
40
Renal disease
Vitamin D deficiency
41
What are trace elements
Dietary minerals required in minute quantities for the normal function
42
Examples of trace elements
```
Calcium
Phosphorus
Iron
Selenium
Zinc
Copper
```
43
Calcium deficiency
Osteoporosis
Paresthesia
Muscle spasms
(from dairy)
44
Phosphorus deficiency
Bone pain, pseudofractures and proximal muscle weakness
or rickets and short stature in children
neurological manifestations
(seeds, nuts, lentils, soya)
45
Iron deficieny
Anaemia, impaired cog development
| red meat, dark veg
46
Selenium deficiency
Cardiomyopathy
| seafood, red meat, cereal
47
Zinc deficiency
Growth retardation, alopecia, dermatitis, diarrhoea, congenital malformations
(meat, shellfish, nuts, legumes)
48
Copper deficiency
Growth retardation, anaemia
| shellfish, liver, nuts, legumes
49
Amount of deaths from malnutrition
1/3
50
What is kwashiorkor
Protein wasting disease
causes acites
micronutrient and antioxidant deficiency
usually in older children
51
What is marasmus
Severe malnutrition of all types of energy sources
Muscle wasting
usually in neonates
52
What is refeeding syndrome
Severe electrolyte disturbance (low serum levels of phosphate, magnesium and potassium and metabolic abnormalities in under-nourished patients undergoing refeeding)
53
What can refeeding cause
```
Respiratory failure (pulmonary oedema)
Confusion
Coma
Cardiac failure
Death
```
54
Pathophysiology of refeeding syndrome
o 1) Starts with chronic malnutrition and fasting
o 2) leads to reduced insulin, increased glucagon and increased cortisol
o 3) Increased glycogenolysis, gluconeogenesis and protein catabolism
o 4) Reduced electrolytes, proteins, fats, minerals and vitamins
o 5) When refeeding occurs, insulin secretion occurs
o 6) Intracellular synthesis of proteins and glycogen occurs
o 7) This requires increased uptake of thiamine, phosphorus, mangesisum and potassium
o 8) Leading to low levels in the serum and also sodium and water retention
o 9) Causes convulsion, wernicke’s encephalopathy, hypotension, arrhythmias, heart failures, renal failure.
55
Management of refeeding syndrome
```
Electrolyte replacement
Nutritional supplement
(simple sip drinks, early ng feeding, parenteral vitamins)
Treat underlying medical problems
Early dietician review
Cardiac monitoring
```
56
How many adults in the UK affected by malnutrition
>2 million adults
| 2wice as common in old age and 3x in institutional care
57
Why is nutrition important
Wound healing, immune system, cardiac function, muscle strength, inactivity (DVT, pressure sores), depression
58
Normal uses of iron
O2 transport in haem
| Myoglobin function in muscles
59
Where is iron absorbed
| how is it transferred and stored
Absorbed in upper bowel
Transferrin-iron protein transport in serum
Iron stored in lever and bone marrow as ferritin
60
What do haem chelators do
Prevent iron overload/oxidative damage in patients
61
Iron deficiency
Microcytic anaemia
Lethargy and fatigue - adults
Cognitive impairment (children)
Exacerbation of inflammatory states
62
Iron excess
Haemochromatosis - Lethargy and fatigue, abdominal and joint pain, reduced libido, bronzing of skin, diabetes, cirrhosis, cardiomyopathy
63
Calciferol
Ergo-D2
| Chole - D3
64
Calcidiol
25-hydroxyvitamin D
65
Calcitriol
1a 25-dihydroxyvitamin D
- short half life
- linked to PTH production
- not a good reflection of vitamin D status
66
How much sunlight do caucasians need
20-30 minutes of sunlight
2000iU vitamin D
2/3 exposures a week in summer
67
How much sunlight do non-caucasians need
Require 2-10 times than Caucasians
| e.g cod liver oil, salmon, mackerel, milk
68
Which months does UK have insufficient UV
October - March
69
Contributing factors to vitamin d deficiency
Obesity
Smoking + betel nut (reduces calcitrol)
Alcohol
Exercise
70
What percent of UK have insufficient vitamin D
50%
| in winter 16% have severe deficincy
71
What are rickets
In children prior to epiphyseal fusion
Growth retardation
Expansion of the growth plate
72
Osteomalacia
Reduced bone strength, increased bone fracture, bone pain, waddling gait
73
Vitamin D guidelines
```
<25nmol/l = deficient
>75 nmol/l = adequate
RDA guidelines
- <1yrs- 400 IU
- 1-70yrs - 600IU
- >70yrs - 800IU
```
74
Where is thiamine/B1 absorbed
Jejunum
75
What is thiamine/vitamin b1 involved in
Glycolysis and Krebs cycle
Involved in BCAA metabolism
Involved in pentose phosphate metabolism
76
What is thiamine deficiency seen in
Alcoholism
Anorexia
Weight loss
= causes cognitive impairment and muscle weakness
77
Types of Beri beri (b1 def)
Dry
Shoshin
Wet
78
What is dry beri beri
Symmetric peripheral neuropathy
79
What is shoshin beri beri
Fulminant cardiac failure
| Lactic acidosis
80
What is wet beri beri
- Cardiac (enlarged heart, tachycardia, high out put CCF, peripheral oedema)
- Neurological (peripheral neuritis)
81
Wernicke's encephalopathy
Horizontal nystagmus
Ophalmoplegia
Cerebellar ataxia
Metal impairment
82
What does niacin/B3 deficiency cause
Pellagra
83
What are the symptoms of early pellagra
```
Loss of appetite
Generalised weakness
Irritability
Abdominal pain
Vomiting
Bright red glossitis
```
84
Symptoms of late pellagra
```
Casal's necklace - skin rash of area exposed to sunlight
Vaginitis
Oesophagitis
Diarrhoea
Depression
Seizures
```
85
4 Ds of pellagra
Dermatitis
Diarrhoea
Dementia
Death
86
What is hartnup's disease
Congenital defect of kidney and intestinal absorption of tryptophan
87
What is carcinoid syndrome
Increased conversion of tryptophan to serotonin
88
Two forms of niacin
Nicotinic acid
nicotinamide
Form two pyridine nucleotides (NAD and NADP) which act as hydrogen acceptors in many oxidative reactions and their reduced forms (NADH and NADPH) act as hydrogen donors in reductive reactions.
89
Niacin toxicity
```
Flushing
Glucose intolerance
Macular oedema
Macular cysts
Fulminant hepatitis
```
90
Vitamin B12 deficiency - haematological issues
Megaloblastic anaemia
| Neutropaenia and thrombocytopaenia
91
Vitamin B12 deficiency - Gastrointestinal issues
Beefy red glossitis
Malabsorption and diarrhoea
Anorexia
92
Vitamin B12 deficiency - Neurological problems
Sensory disturbance
Gait abnormalities
Memory loss and disorientation
93
Vitamin B12 absorption
Dissociated from proteins in stomach
Complexes with intrinsic factor in small intestine
Absorbed via specific receptors in the terminal ileum
40% absorbed - the rest
94
Which other forms is vitamin B12 available as
o Cyanocobalamin used therapeutically
| o Cofactor for methionine synthase and methylmalonyl–coenzyme A (CoA) synthase
95
Causes of vitamin B12 deficiency
```
inadequate intake - vegans
Disorders of terminal ileum
o Defective release of cobalamin from food
o Inadequate production of IF
o Transcobalamin II deficiency (rare)
o Congenital enzyme defects (rare)
```
