Micronutrients Flashcards
Define micronutrients
Essential compounds required in small amounts in the diet
What is the role of micronutrients in adults
Maintaining homeostasis
What is the role of micronutrients in paeds
Energy suppluy
What does RDA stand for
Recommended dietary allowance
Name four vitamins that are fat soluble
A, D, E and K
Can fat soluble vitamins be stored
Yes
Which type of vitamins (fat soluble vs water soluble) can be toxic
Fat soluble (water soluble excess lost in urine)
Name four water soluble vitamins
B, folate, biotin, C
Do water soluble or fat soluble vitamins usually act as coenzymes
Water soluble
Name some causes of decreased vitamin intake in developed countries
- Alcohol dependency
- Small bowel disease
- Vegans
- Elderly with poor diet
- Anorexic people
What deficiencies are common in alcohol dependency
Vitamin B
What causes of decreased intake vitamin deficiency can cause vitamin B9 deficiency
Small bowel disease
Elderly with poor diet
Anorexia
What are vegan usually deficient in
Vitamin B
Vitamin B12
What can cause decreased absorption vitamin deficiency in the developed world
Ileal disease
Liver and biliary tract disease
Intestinal bacterial growth
Oral antibiotics
What are the 3 things that most commonly cause all deficiencies in the developed world
Fat malabsorption
Alcoholism
Liver disease
What factors can contribute to vitamin A deficiency
Infection, measles, protein energy malnutrition
Clinical features of vitamin A deficiency
Xerophthalmia
Contributing factors to vitamin D deficiency
Ageing
Lack of sunlight exposure
Clinical features of vitamin D deficiencies
Rickets
Osteomalacia
Contributing factor to vitamin E deficiency
Antibiotic use
Clinical feature of vitamin E deficiency
Peripheral neuropathy
Cause of vitamin K deficiency
Antibiotic use
Clinical feature of vitamin K deficiency
Coagulopathy
Cause of vitamin C deficiency
Smoking
Clinical features of vitamin C deficiency
Scurvy
What is the clinical feature of B1 deficiency
beri beri
What is the clinical feature of B2 deficiency
Angular stomatitis
What is the clinical feature of b3 deficiency
Pellagra
What is the clinical feature of b6 deficiency
Neuropathy
Anaemia
What is the clinical feature of b12
Anaemia
What is the clinical feature of b9 deficiency
Anaemia
Define trace elements
Dietary minerals necessary in minute quantities for the normal function of organism
What happens when you are calcium deficient
- Osteoporosis
- Paresthesia
- Muscle spasms
What happens if you have a phosphorus deficiency
- Bone pain
- Pseudofractures
- Proximal muscle weakness
- Rickets
- Short stature in children
What happens if you have an iron deficiency
Anaemia
What happens if you have selenium deficiency
Cardiomyopathy
What happens if theres a zinc deficiency
Growth retardation Alopecia Dermatitis Diarrhoea Congenital malformations
What happens if there’s a copper deficiency
Growth retardation
Define refeeding syndrome
Severe electrolyte disturbance and metabolic abnormalities in patients undergoing refeeding whether orally, enterally, paraenterally
What are the long term consequences of refeeding syndrome
Pulmonary oedema, confusion, coma, cardiac failure and death
What metabolic changes happen during chronic malnutrition
Low insulin, high glucagon and cortisol
Gluconeolysis, gluconeogenesis, protein catabolism
Depletion of electrolytes, proteins, fats minerals and vitamisn
What is secreted when refeeding occurs after chronic malnutrition
Insulin
What is the effect of insulin on protein and glycogen synthesis
Increases
Describe what happens in refeeding at a cellular level
- Increased glucose uptake
- Increased phosphorus, magnesium and potassium
- Increased thiamine use
How do the levels of electrolytes change after refeeding
Hypophosphataemia Hypokalaemia Hypomagnesaemia Thiamine deficiency Sodium and water retention
Neurological complications of refeeding syndrome
Convulsions, delerium, ataxia
Cardiovascular complications of refeeding syndrome
Hypotension, arrythmias, heart failure
How should refeeding syndrome be managed
Aggresive electrolyte replacement
Nutrional supplementation
Treat underlying medical problem
What are the main functions of iron
Oxygen transport
Myoglobin function in skeletal muscle
Absorbed in small bowel
Signs and symptoms of excess iron
Lethargy and fatigue Abdominal and joint pain Reduced libido Bronzing of skin Diabetes Cirrhosis
Other than sunlight deficiency, what can cause vitamin D deficiency
Obesity
Smoking
Alcohol
Exercise
Signs and symptoms of osteomalacia
Reduced bone strength Increase in bone fracture Bone pain Bending of bones Muscle weakness Waddling gait
Name 3 groups of people who require more vitamin D
Pregnant/ breastfeeding women
People with low sun exposure
Age >65 years
What can happen as a result of thiamine deficiency
Wernickes Encephalopathy and Korsakoff’s psychosis
What is another name for vitamin B1
Thiamine
Where is thiamine absorbed
Jejunum
What is vitamin B1 involved in
- Involved in glycolysis and krebs cycle
- Involved in BCAA metabolism
- Involved in pentose phosphate cycle metabolism
When is vitamin B1 deficiency most commonly seen
- Malignancy
- Alcoholism
Signs and symptoms of thiamine deficiency
Cognitive impairment
Cognitive impairment
Muscle weakness
What is another name for thiamine deficiency
Beri beri
Symptoms of dry beri beri
Symmetric peripheral neuropathy
What are the symptoms of shoshin beri beri
Fulminant cardiac failure
Lactic acidosis
What are the symptoms of wet beri beri
Cardiac symptoms such as enlarged heart, tachycardia, high output ccf, peripheral oedema
Peripheral neurititis
What are the symptoms of Wernicke’s encephalopathy
Horizontal nystagmus
Ophthalmoplegia
Cerebellar ataxxia
Define Wernicke-Korsakoff syndrome
Mental impairment with additional loss of memory and a confabulatory psychosis
What is another name for vitamin b3
Niacin
Where is niacin absorbed
Jejunum
What does niacin form
NAD and NADP which act as hydrogen acceptors in many oxidative reactions
What can cause niacin deficiency
Vegetarian diets
Alcoholism
What is Hartnup’s disease
Congenital defect of intestinal and kidney absorporption of tryptophan leading to vit b3 deficiency
How does carcinoid syndrome lead to vitamin b3 deficiency
Increased conversion of tryptophan to serotonin
Signs and symptoms of early pellagra/ b3 deficiency
Loss of appetite Generalised weakness Irritability Abdominal pain Vomiting Bright red glossitis
Signs and symptoms of late pellegra
Casals necklace Vaginitis Oesophagitis Diarrhoea Depression Seizures
What is Casals necklace
Skin rash particularly in areas expsoed to sunlight
What are the signs and symptoms of pathologically high b3 levels
Flushing
Glucose intolerance, macular oedema and cysts
Fulminant hepatitis
Describe how vitamin B12 is absorbed in the body
Dissassociated from proteins in stomach
Complexes with intrinsic factor in small intestine
Absorbed via specific receptors in terminal ileum
What % of B12 is absorbed and what is excreted
40% absorbed
60% excreted
Common causes of b12 deficiency
Inadequate intake
Disorders of terminal ileum
Defective release of cobalamin from food
Inadequate IF productive
What are the forms of haematological b12 deficiency
Megaloblastic anaemia
Neutropaenia and thrombocytopaenia
Neurological symptoms of b12 deficiency
Sensory disturbance, gait abnormalities, memory loss and disorientation
Gastrointestinal symptoms of b12 deficiency
Beefy red glossitis
Malabsorption and diarrhoea
Anorexia
