Nutrition Flashcards
What is vitamin B6
Vitamin B6 is a water soluble vitamin of the B complex group.
It is converted to pyridoxal phosphate (PLP) which is a cofactor for many reactions including transamination, deamination and decarboxylation.
Causes of vitamin B6 deficiency
isoniazid therapy
Consequences of vitamin B6 deficiency
peripheral neuropathy
sideroblastic anemia
vitamin B6 is also known as
pyridoxine
Vitamin C is also known as
ascorbic acid
Vitamin C Functions
antioxidant
collagen synthesis
facilitates iron absorption
cofactor for norepinephrine synthesis
Vitamin C deficiency (scurvy) leads to
defective synthesis of collagen resulting in capillary fragility (bleeding tendency) and poor wound healing
Features vitamin C deficiency
gingivitis, loose teeth
poor wound healing
bleeding from gums, haematuria, epistaxis
general malaise
Vitamin A is water solubke
false
fat soluble
Vitamin A/retinol Functions
converted into retinal, an important visual pigment
important in epithelial cell differentiation
antioxidant
Consequences of vitamin A deficiency
night blindness
Name all the Vitamin B types
B3 Niacin B6 Pyroxidine B7 Biotin B9 Folic Acid B12 Cyanocobalamin
Deficiency of Thiamine leads to?
Beriberi
polyneuropathy, Wernicke-Korsakoff syndrome
heart failure
Deficiency of Niacin leads to?
Pellagra
dermatitis
diarrhoea
dementia
Deficiency of Pyridoxine leads to?
Anaemia, irritability, seizures
Deficiency of Biotin leads to?
Dermatitis, seborrhoea
Deficiency of Vitamin D leads to?
Rickets, osteomalacia
Deficiency of Vitamin E leads to?
Mild haemolytic anaemia in newborn infants, ataxia, peripheral neuropathy
Deficiency of Vitamin K leads to?
Haemorrhagic disease of the newborn, bleeding diathesis
NICE define malnutrition as the following:
a Body Mass Index (BMI) of less than 18.5; or
unintentional weight loss greater than 10% within the last 3-6 months; or
a BMI of less than 20 and unintentional weight loss greater than 5% within the last 3-6 months
MUST (Malnutrition Universal Screen Tool) takes into account?
BMI, recent weight change and the presence of acute disease
Management of malnutrition is difficult. NICE recommend the following points:
dietician support if the patient is high-risk
a ‘food-first’ approach with clear instructions (e.g. ‘add full-fat cream to mashed potato’), rather than just prescribing oral nutritional supplements (ONS) such as Ensure
if ONS are used they should be taken between meals, rather than instead of meals
Niacin is a water soluble vitamin of the B complex group. It is a precursor to
NAD+ and NADP+ and hence plays an essential metabolic role in cells.
Hartnup’s disease:
hereditary disorder which reduces absorption of tryptophan
carcinoid syndrome:
ncreased tryptophan metabolism to serotonin
Thiamine is therefore important in
catabolism of sugars and aminoacids
clinical consequences of thiamine deficiency are therefore seen first in which type of tissues
clinical consequences of thiamine deficiency are therefore seen first in highly aerobic tissues such as the brain (Wenicke-Korsakoff syndrome) and the heart (wet beriberi).
Causes of thiamine deficiency:
alcohol excess. Thiamine supplements are the only routinely recommend supplement in patients with alcoholism
malnutrition
Wernicke’s encephalopathy features?
nystagmus, ophthalmoplegia and ataxia
Korsakoff’s syndrome features?
amnesia, confabulation
dry beriberi is what secondary to thiamine defiency?
peripheral neuropathy
wet beriberi is what secondary to thiamine defiency?
dilated cardiomyopathy
Symptoms and signs include of scurvy
Follicular hyperkeratosis and perifollicular haemorrhage
Ecchymosis, easy bruising
Poor wound healing
Gingivitis with bleeding and receding gums
Sjogren’s syndrome
Arthralgia
Oedema
Impaired wound healing
Generalised symptoms such as weakness, malaise, anorexia and depression
Total iron binding capacity (TIBC) raised in?
raised in iron deficiency anaemia (IDA)
raised in pregnancy and by oestrogen
Ferritin raised/ low in?
raised in inflammatory disorders
low in IDA
Anaemia of chronic disease bloods?
normochromic/hypochromic, normocytic anaemia
reduced serum and TIBC
normal or raised ferritin
Ferritin is an acute phase protein
true
may be synthesised in increased quantities in situations where inflammatory activity is ongoing. Falsely elevated results may therefore be encountered clinically and need to be taken in the context of the clinical picture and blood results.
We can split the causes of increased ferritin levels into 2 distinct categories based on?
Without iron overload (around 90% of patients) With iron overload (around 10% of patients)
increased ferritin levels
Without iron overload (around 90% of patients)
causes?
Inflammation (due to ferritin being an acute phase reactant) Alcohol excess Liver disease Chronic kidney disease Malignancy
increased ferritin levels
With iron overload (around 90% of patients)
causes?
Primary iron overload (hereditary haemochromatosis)
Secondary iron overload (e.g. following repeated transfusions)
The best test to see whether iron overload is present is transferrin saturation.
true
Ferritin levels may be decreased in
Because iron and ferritin are bound the total body ferritin levels may be decreased in cases of iron deficiency anaemia.
