Malnutrition Flashcards
why is nutrition important?
- Essential to support growth, maintenance and repair tissues
- Common health problems can be prevented with balanced diet
what type of energy does carbohydrates provide?
Provide readily available source of chemical energy to generate ATP to drive metabolic reactions
what are the different types of carbohydrates?
- determined by number of monomers
- polysaccharides (glycogen, starch, cellulose)
- disaccharides (sucrose, lactose, maltose)
- monosaccharides (glucose, fructose, galactose, deoxyribose, ribose)
what are triglycerides and how much energy do they provide?
- Triglycerides-most plentiful lipid, more than twice as much energy as carbohydrate or protein
- each contains a glycerol molecule with 3 fatty acids.
- They can be saturated, polyunsaturated and monounsaturated
what type of lipids can the body not produce?
essential fatty acids
what are phospholipids?
consists of glycerol backbone with 2 fatty acid chains and also a phosphate group (amphipathic), found in cell membranes
what are the 2 main nutritional requirements?
macronutrients
micronutrients
what are macronutrients?
Macronutrients-needed in large quantities for energy and organic building materials
-carbohydrates, proteins, lipids
what are micronutrients?
needed in smaller quantities for special biochemical functions
-minerals, trace elements, vitamins
what are proteins?
Large range of function and more complex
Made up of amino acids
Amino acids joined by peptide bonds
what are the functions of proteins?
- structural (collagen in bone)
- regulatory (hormones like insulin)
- contractile (myosin and actin in muscle cells)
- immunological (antibodies)
- transport (haemoglobin)
- catalytic (enzymes)
give examples of proteins?
- Steroids
- cholesterol
- bile salts
- adrenocortical hormones
- sex hormones
- eicosanoids
- lipoproteins
what are eicosanoids?
lipids derived from fatty acids called arachidonic acid, sublasses=prostaglandins and leukotrienes, involved in inflammatory reactions, gastric protection, airway calibre, clotting
what is the function of lipoproteins?
carry triglycerides and cholesterol around the body
what are minerals and give examples?
- Inorganic elements
- Ions in solutions, in combination with each other or in combination with organic compounds
- Calcium, phosphorus, potassium, sulphur, sodium, chloride, magnesium, iron, iodide are in the body in quantities greater than 5 grams
what are vitamins and how are they absorbed?
- Organic nutrients not synthesised by the body but are vital for metabolism and maintenance of growth
- Most are coenzymes
- Do not provide energy
- Water soluble are absorbed along with water (B1, B2, B6, B12, C, folate, niacin) or fat soluble which are absorbed with other dietary lipids in small intestine and dependent on bile salts (A, D, E, K)
what are trace elements?
- Inorganic elements in body in quantities less than 5 grams
- Manganese, copper, cobalt, zinc, fluoride, selenium, chromium
which vitamins are antioxidants and what do they do?
C, E and beta-carotene act asantioxidants, they inactivate oxygen free radicals to prevent damage to DNA, cell membranes and structures in the cell
what is basal energy expenditure?
how much of this do people usually consume to stay at steady state?
energy used at rest for metabolism
1.5x basal energy expenditure
how much of calorie intake should come from
- carbohydrates
- fats/lipids
- proteins
- 50-60%
- 30%
- 10-15%
how do you calculate BMI?
weight (kg) / height (m2)
what factors affect the calculation of basal energy expenditure?
weight needed to achieve activity level illness growth/pregnancy temperature
describe the issue of malnutrition in hospital?
- High prevalence of undernutrition seen in patients admitted to hospital: 20-40%, Particularly seen in patients with poverty or alcoholism
- Whilst an inpatient this has the potential to escalate further: Secondary to pathological processes - increase the metabolic demand. Neglect – by patient (dislike of meals)+ medical staff. “Nil By Mouth” for tests, clinical reasons, etc
- Nutritional support is required in many cases to aid recovery from extensive metabolic changes that accompany illness
what are the types of nutritional support?
Enteral (oral and tube feeding)
Parenteral (administered intravenously)
describe the need to adjust protein content?
Amino acids are required to make proteins, Nitrogen balance is a term used to assess amino acid flux, Mean requirement for protein is measured in grams of nitrogen (g N) per day: 9 grams for men/7.5 grams for women. Dietary protein requirements to remain in nitrogen balance varies with age, sex and metabolic state and can be monitored by checking urinary urea excretion
what is the main source of carbohydrate and what does it supply?
Glucose is the main energy source. Essential for energy supply to Red Blood Cells + Brain
describe fats/lipids as an energy source?
Provide a good energy source. No less than 5% of total calories should be provided as lipids in order to prevent fatty acid deficiency
describe basic electrolyte requirements?
- Na - weight in kg as mmol/24hr
- K+ - weight in kg as mmol/24hr
- Ca - 5-10 mmol/day
- Mg - 5-10 mmol/day
- PO4 - 10-30 mmol/day
what are the types of enteral feeding?
- oral supplements
- tube feeding
- enterostomy feeding
describe oral supplements?
calogen, fresubin, fortisips.
Rich in macronutrients and are an addition to normal diet
describe tube feeding?
-patients with inadequate or unsafe oral intake via a fine bore nasogastric tube. Nasojejunal tube an be inserted in presence of gastroparesis or pancreatitis. Continuous drip feeding is generally better than bolus. Complications include-insertion of tube into lungs, aspiration, nasal erosion, refeeding syndrome
describe enterostomy feeding?
generally considered if feeding for longer than 4-6 weeks. Usually inserted using PEG-percutaneous endoscopic gastrostomy. Risks include perforation, peritonitis, infected site, buried bumper syndrome, aspiration
when is parenteral feeding considered?
considered for patients who are-malnourished or at risk, unsafe oral or enteral intake, non-functional, inaccessible or perforated GI tract
what is the route for parenteral feeding?
Short term feeding (< 14 days) a peripheral cannula can be used if no need for CV access – thrombophlebitis common problem + often limits use. PICC line (peripherally inserted central catheter via basilic vein. Central venous catheters: (Tunnelled subclavian line for use >30 days or Non-tunnelled CVL for use < 30 days)
what are the complications of parenteral feeding?
Risks of central venous catheter insertion. Catheter related infection, blockage, venous thrombosis, fatty liver disease
what needs to be monitored in patients with decreased oral intake?
-Doctors and Health care professionals need to monitor:
-Before feeding is commenced patients need bloods to check electrolyte/vitamin levels. Bloods to check include: FBC, UE, LFT, Mg, PO4, Cu, Selenium + B12/Folate
-Ensure total intake of prescribed nutrition accounts for losses
Review the indications, route, risks, benefits and goals of nutrition support daily
-Monitor weight daily then twice weekly once stable
-Monitor fluid balance charts
-Assess for nausea/vomiting, diarrhoea, constipation
-Check tube positions , stomas or line insertion sites
-Blood tests to monitor for refeeding syndrome
-Close liaison with dietician is required
what is refeeding syndrome?
Refeeding syndrome is a complication resulting from too rapid reintroduction of feed following starvation
can occur in enteral or paranteral feeding
describe the pathophysiology of refeeding syndrome
-Results from a reduced carbohydrate intake secondary to starvation producing low insulin levels.
-Once feeding restarted increased insulin secretion occurs, which increases cellular uptake of PO4.
Phosphate levels fall resulting in rhabdomyolosis, leucocyte dysfunction, respiratory/cardiac failure, muscle weakness, seizures, coma.
-Usually occurs around day 4 of refeeding
what patients are at high risk of refeeding syndrome?
BMI < 16kg/m2
History of alcohol abuse
Little or no nutritional intake for last 10 days
Low levels of potassium
phosphate or magnesium prior to commencing feed
Unintentional weight loss of > 15% last 3-6 months
what do patients at high risk of refeeding syndrome require?
require additional vitamin supplements – thiamine/vitamin B/trace elements
what is the treatment for refeeding syndrome?
monitoring FBC, UEs, PO4, and Mg daily and replacing as necessary
what is malabsorption?
any pathology that impairs the digestion through brush border enzymes, the absorptive proves (from the quality of the epithelium to its surface area) and (impaired) gut motility
what are the signs and symptoms of malabsorption?
Diarrhoea Steatorrhea Abdominal bloating Gas Weight loss
give examples of disorders causing malabsorption?
Coeliac disease Crohn’s disease Dermatitis herpetiformis Tropical sprue Bacterial overgrowth Intestinal resection Whipple’s disease Radiation enteritis Parasite infection
how are malnourished patients identified?
Nutritional support should be considered in people who are malnourished: BMI less than 18.5 kg/m2, Unintentional weight loss greater than 10% within last 3-6 months, BMI less than 20 kg/m2 + unintentional weight loss greater than 5% in last 3-6 months
what patients are at risk of malnutrition?
Eaten little or nothing for more than 5 days and/or likely to eat very little for the following next 5 days. Have poor absorptive capacity +/- high nutrient loss +/- increased nutritional needs due to increased catabolism
where is gluten found?
Gluten is found in grains and starches (wheat, wheat germ, rye, barley, bulgur, couscous, graham flour, semolina, malt).
why might a gluten free diet be needed?
coeliac disease, gluten sensitivity (milder form of gluten intolerance. This can be associated with maldigestion), wheat allergies
is there any benefit to healthy people of having a gluten free diet?
there is no known benefit to cut out gluten. Often gluten free products are more expensive than ordinary products
