14. Nutrition and malnutrition Flashcards
What are the healthy eating guidelines?
- 5 portions of fruit/vegetables a day
- Base meals on starch carbohydrates (wholegrain preferable)
- Have some dairy (lower fat/sugar preferable)
- Proteins (including 2 portions of fish ever week, one of which should be oily)
- Choose unsaturated oils
- 6-8 glasses of fluid a day
How does the reality compare to the recommendations of healthy eating?
- Less than 40% of adults and less than 10% of children consume the recommended 5 a day
- Saturated fat intake exceeds recommendation (meat and dairy provide 45% of this)
- > 85% consume higher than recommended free sugars
What is enteral and parenteral feeding?
- Enteral - delivery of nutritious fluid past the upper GI tract, into the stomach/duodenum/jejunum
- Parenteral - delivery of nutrients via IV catheter, bypassing the GI tract (can take more than 12 hours)
What kind of patient is treated with enteral and parenteral feeding?
- Enteral - temporary upper GI problem e.g. dysphagia or trauma
- Parenteral - dysfunction of GI tract, unable to digest/absorb/excrete
What are the risks of enteral and parenteral feeding?
- Enteral (low risk) - nausea, vomiting, aspiration
* Parenteral (high risk) - pneumothorax, blood clots, infection, liver failure
What are the technical requirements, effects on GI tract and costs of enteral and parenteral feeding?
- Enteral - basic training, maintains internal structure and function of GIT, cheaper
- Parenteral - specialist training, atrophy of GIT due to underuse, expensive
What is short bowel syndrome?
- Lack of functional small intestine
- Characterised by significant removal of the bowel - left with less than 100cm of functional intestinal tract
- Can be caused by Crohn’s, cancer, ischaemia, ulcerative colitis, irradiation
- Leads to dehydration, malnutrition
How can short bowel syndrome be managed?
- Provide adequate nutrition
- Ensure adequate water and electrolytes to maintain homeostasis
- Correction and prevention of acid base imbalance
• Anastamosis - connection of small intestine to colon - important surgical intervention, can reduce reliance on parenteral nutrition
What is adaptive thermogenesis?
Amount of energy needed to keep warm and absorb nutrients
older, loss of muscle, lower energy intake
What is re-feeding syndrome?
- Metabolic disturbances as a result of reinstitution of nutrition to patients who are starved/severely malnourished
- Arrhythmia, respiratory distress, weakness
How do you managed re-feeding syndrome?
- Daily biochemistry and replace electrolytes
- Vitamin supplementation for first 10 days of feeding
- Start low, increase slowly
What is thiamine and what can a deficiency lead to?
• Vitamin B1
• Involved in the breakdown of energy molecules e.g. glucose
• Found on the membranes of neurones
• Deficiency: beriberi - lethargy, fatigue, CV, nervous, muscular and GI symtpoms
(could be caused by humans - thiamine of white rice removed by polishing)
What is niacin and what can a deficiency lead to?
• Nicotinamide is a derivative
- used to form coenzymes NAD and NADP
• Deficiency: Pellagra
What are the signs of malnutrition?
• Weight loss - loss of subcutaneous fat - muscle wasting • Peripheral oedema • Glossitis • Hair loss • Chronic infections • Poor wound healing
What factors affect the metabolism of alcohol?
- Diet
- Genetic
- Gender
- Body habitus (physique)
- Race
What negative effects does alcohol have on the body?
- CNS - Wernickes encephalopathy
- CVS - hypertension
- GIT - oesophagitis, alcoholic hepatitis, pancreatic cancer etc.
- Glomerulonephritis, gout, pseudocushings, impotence etc.
What effect does alcohol have on immunity?
- Immunosuppression - increased incidence of infectious disease
- Autoimmunity - liver cirrhosis, renal disease associated with IgA deposition
Outline the metabolism of ethanol?
• Ethanol => acetaldehyde [alcohol dehydrogenase/catalase/Cytochrome P450-2e1]
• CYP2E1:
- is an inducible enzyme - heavy drinking can still be metabolised effectively
- creates reactive oxygen species - tissue damage, inflammation and stimulation of immune system (fibrosis etc.)
• Acetaldehyde => CO2 + H20 [aldehyde dehydrogenase]
• ALDH - genetic polymorphisms for this gene
What is a fatty liver?
- Fat droplets deposited in the liver
- Can lead to steatohepatitis and abnormal LFTs
- Reversible if alcohol reduced
What is hepatic fibrosis?
- Migrating macrophages
- Chronic inflammation
- => hepatic stellate - lay down collagen fibres
Describe cirrhosis
- Asymptomatic
- Irreversible scarring of liver with fibrous bands and regenerative nodules
- Eventually develops in 20% after 15 years
- Morbidity common - associated with jaundice, ascites, bleeding etc.
- Death in most within 10 years
How much alcohol is in one unit?
8g
How do you calculate units of alcohol by volume?
(Percentage volume (g of alcohol in 100ml) x 0.789 x volume drunk)/100
What are the clinical features of acute alcohol poisoning?
- Ataxia and anasthesia
- Dysarthria (slurring of words)
- Nystagmus (involuntary eye twitching)
- Drowsiness => coma
- Inhalation of vomit
What are the effects of alcohol on the male reproductive system?
- Strong Leydig cell toxin
- Adverse effect on synthesis and secretion of testosterone
- Common cause of male impotence
What causes a ‘hangover’?
- Dehydration
* Altered osmolarity of endolymphatics
What is a serious (blood level) complication of acute alcohol poisoning?
Alcohol induced hypoglycaemia
