Lecture 17: Nutrition and Cancer Prevention

Question 1

Cancer: Incidence/Prevalence

Answer 1

• leading cause of death
• Incident: 200,000 cases per year
• Prevalence: 2.4% Canadians
• I/P influenced by environment
• Mortality rates decreased by 32% (males) and 17% (women)

Question 2

Cancer development

Answer 2

• arises in the genes
  
  • DNA is damaged by a carcinogen –> gene instability, hypermutation
  • cell loses ability to self-destruct –> (apoptosis) no signal for it so it continues to copy itself and divide very rapidly
  • mass of abnormal tissue
  • loss of proliferation control

Question 3

cancer stages

Answer 3

0) a group of abnormal cells
1) small and has not grown outside the organ
2) larger, but has not spread to nearby tissues
3) large, has spread to nearby tissues and lymph nodes
4) spread through the blood or lymphatic system to a distant site in the body

Question 4

Mechanisms of Diet Induced Carcinogenesis

Answer 4

• Carcinogenic exposure
  
  • Absorption
  • Distribution
  • Biotransformation (Liver, Kidney, Lungs)
    
    • Activation
      
      • Genotoxic mechanism
        
        • DNA adducts
        • chromosome breakage, deletion, fusion, non-dysjunction
      • Non-Genotoxic Mechanism
        
        • Inflammation
        • Immunosupression
        • Reactive oxygen species
        • Reactive nitrogen species
        • Receptor activation
        • Epigenetic silencing
    • Inactivation
      
      • Excretion (Kidney)

Question 5

Total Calorie Intake

Answer 5

• calorie restriction (CR), by 20-40% –> reduced cancer tumor development
• Norwegian women (WW2): decreased breast cancer risk later in life with acute (<1 year) energy restriction (~50%)
• potential mechanisms: telomere shortening/angiogenic factors

Question 6

Fatty Acid and Risk of Cancer

Answer 6

• lack of evidence increased fat ( 20%

Question 7

Meats and Risk of Cancer

Answer 7

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