Nutrition and cancer Flashcards
What is the name of the protein energy malnutrition in cancer patients and what is it caused by?
Cachexia - occurs due to a systemic inflammatory response that is mediated through cytokines
What are the consequences of losing weight for cancer patients?
They don’t respond as well to cancer treatment, they are more likely to die in surgery treatment, they are more likely to have a worse quality of life and they are more likely to die.
What factors can contribute to cachexia in cancer patients?
- Physcial impairment of swallowing
- mainly in head and necck cancers
- possible due to reduction in saliva (xerostomia) or induce mucositis due to chemo or radiation (Mucositis is the painful inflammation and ulceration of the mucous membranes lining the digestive tract, usually as an adverse effect of chemotherapy and radiotherapy treatment for cancer.) - Alterations in metabolism.physiology
- increased protein catabolism/loss, increased fat breakdown, increased cori cycle, increased overall energy use, abnomral response to insulin and glucose intolerance
- often in cancer of the GI tract there is problems with maldigestion and malabsorption. There may also be bowel motility problems resulting in diarrhea or constipation - Inadequate dietary intake
- suppression of appetite due to the effects of drugs and perhaps emotional depression
- often there is food aversion because of the associated symptoms after eating (nausea, vomiting)
What are some of the medical nutrition treatments for cancer patients with weight loss?
Supplemental feeding - add supplements to meals to increase energy/protein content
Advice
Enteral feeding - use of nasogastric tube or gastrostomy (a PEG is a percutaneous endoscopic gastrostomy where a tube is enter through the abdo wall into the stomach. A stoma is present on the abdo wall).
Total parenteral nutrition - feeding through the veins
Nutraceutica agents - fortified food products/ supplments
What is the difference in glucose turnover in patients with cachexia compared to people with starvation? How is this evident in their blood?
- In cachexia the glucose turnover is increased whereas in starvation it is reduced to try and conserve energy
- This reflects the unchanged serum glucose and insulin levels in cachexia but the decreased levels in people with starvation
- Also because patients with cachexia use a lot of glucose in the cells, there is a large production of lacctate (an increase in serum lactate) and they also have an increase in the cori cycle (refers to the metabolic pathway in which lactate produced by anaerobic glycolysis in the muscles moves to the liver and is converted to glucose, which then returns to the muscles and is metabolized)
What is the difference between lipid breakdown in people with cachexia as opposed to people with starvation?
Lipolysis is increased in both cachexia and starvation however in starving the enzyme levels are unchanged whereas in cachexia there is a decrease in lipoprotein lipase but an increase in serum triyglyceride (increase in fat in the blood).
What is the difference in protein breakdown and nitrogen balance in patients with cachexia as opposed to starvation?
In both cases there will be negative nitrogen balance.
In patients with cachexia this will be due to an increased protein turnover and skeletal muscle breakdown.
In people with starvation there will not be increased protein turnover or muscle breakdown as the body tries to conserve it but the body will go into negative nitrogen balance as there is not enough nitrogen consumed to replace what is lost in the urine.
What signals do the lipid mobilizing factors produced from a tumour send?
Signal to the fat to increase lipid breakdown
What signals do the cytokines produced from a tumour send?
Signal to the hypothalamus to increase energy expenditure/glucose turnover and to the liver to elicit an inflammatory response.
What signals do the hormones or proteolysis inducing factor produced from the tumour send?
Send signals to the skeletal muscle to increase amino acid breakdown.
