TOPIC 9: Diet and Disease LESSON 1: Diet & Cancer VIDEO #1 Causes of Cancer - Diet & Obesity – 30-35% - Tobacco – 25-30% - Infections – 15-20% - Radiation – 10% - Pollution – 3-5% - Alcohol / Sexual – 3-5% - GENETICS – 5-10% o Check study below: even with genetic factors, environmental factors DOMINATE Study about Identical Twins - Scandinavia: 45,000 pairs of twins; 10,000 cancers occurred o Some cancers showed heritable factors Stomach Cancer o Environmental Shared – 10% Non-shared – 62% o Heritable – 28% Cervical Cancer o Environmental -- HIGH o Heritable – LOW Absolute Risks o Identical (monozygotic) twins have ~15% higher risk, Fraternal twins only ~6% CONCLUSION: o Unmistakable hereditary – 1% o Major component hereditary – 15% VIDEO #2 Cancer - Comes from Latin term for crab, bc tumors resembled crabs - More than 1/2 million people in the US die of cancer every year o 1,500 Americans/ day Cancer Trends - At one time, increase in cancer rates mostly bc of better diagnosis - Mortality from cancer is decreasing - NO CANCER EPIDEMIC!!! - Overall, the general cancer rates are the same - Breast Cancer rates are decreasing o Began decreasing when estrogen supplements for menopause ceased - ENVIRONMENTAL FACTOR : o In some areas, some cancers are more common than others ~90% of the causes are associated with the ENVIRONMENT
o When people migrate from another country, tend to take on cancer patterns of the NEW country - ***PRIMARY CONCERN: among CHILDREN!!!*** o INCREASING slightly, unknown what the actual cause is Diet, environment? 30-40% (4 million cases) a year of all cancers in the world can be prevented!!! - pay attention to environmental factors DIET!!! Prostate Cancer - 5+ servings of fruit a day lowers risk of prostate cancer by 50% - 2,000 mg a day of calcium from food or supplements increases risk of advanced prostate cancer by 300% Overall evidence: consuming fruits and vegetables is beneficial Lemons - Claim: 10,000 times stronger than chemotherapy o WHERE DOES THIS CLAIM COME FROM? Mistranslation from a Spanish document Actually talking about Soursop/Graviola , a tropical fruit o Some studies seem to show small effect Marketers take on this and oversell it Potatoes Protecting Against Cancer and Keeping You Slim - Where does this come from? o Potato juice o Buddhist monk Master Tomizawa who advocates for drinking a glass everyday VIDEO #3 Betel Nuts - Common to eat these in Asia - However contains compounds that can initiate cancer in the mouth Alcohol increases risk of cancers: 1) Mouth 2) Larynx 3) Esophagus 4) Liver 5) Breast o even SMALL amounts can increase risk for breast cancer - One glass a day no problem - Two glasses already poses minor problems Associations - In Japan, meat intake and colorectal cancer are increasing parallel o CANNOT conclude that eating meat causes colorectal cancer
o But there is reason to investigate further Because meat does contain cancer causing compounds, especially if they are cooked in HIGH temperatures Such as Heterocyclic Amines, Benzopyrene - Increases consumption of PROCESSED meats associated with increases risk of colorectal cancer -
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- Spring '11