There are two major types of bacteria in digestive tract that may play a role

There are two major types of bacteria in digestive

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There are two major types of bacteria in digestive tract that may play a role in weight control - the more Bacteroidetes you have, the more likely you are to be lean , the more Firmicutes you have, the more likely you are to be fat. Rodent studies have confirmed this These studies also showed that if the mice get the bacteria from an overweight mouse they would only become overweight if they were fed an inadequate diet, diet matters!! - = bacteria has a role to play ONLY in the presence of a poor diet - Average American consumes half a litre of soft drinks a day (200 extra calories) - cutting this out can lead to a loss of two pounds a month Topic 9: DIET AND DISEASE Lesson 1: Diet and cancer VIDEO 1 CAUSES OF CANCER : - Environment: 90% Diet and obesity: 30-35% - Cancer is most frequent among those branches of the human race where carnivorous habits prevails Tobacco: 25-30% Infections: 15-20% Radiation: 5-10% Pollution: 3-5% Alcohol/sexual: 3-5% - Genetics: 5-10% Study: environmental and heritable factors in causation of cancer (2000, Scandinavia) - 45,000 pairs of twins studied - 10,000 cancers occurred - Some cancers showed heritable factors Stomach cancer - Environmental — Shared = 10% // Environmental — Non shared = 62% 22 of 66
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- Heritable = 28% Cervical cancer - Environmental: high - Heritable: low Absolute risks (risks are averaged over a range) - Monozygotic twins (identical): 15% - Dizygotic twins (fraternal): 6% Conclusion: - Unmistakable heredity: 1% - Major component heredity: 15% Another study on Norwegian Twins: heritability and familial risk of cancer (2013) Monozygotic and dizygotic pairs: 133,689 Prostate cancer heritability (2013)= 58%, whereas prior study (2000) = 42% Other cancer rates lower and varied - CONCLUSION : even with twins, environmental factors strongly dominate VIDEO 2 - The term cancer comes from the Latin for "crab", because originally tumours and their blood vessels seemed to look like crabs with all of their legs - More than half a million people in the United States die of cancer every year About 1,500 Americans a day - Mortality of cancer is decreasing, rate of cancer has increased a bit because of increased ways of detecting it, but overall there is no cancer epidemic Some cancers are falling and some are increasing, but the general cancer rate is about the same Varies with location (environment and diets) Childhood cancer seems to be increasing, but we don’t know why - Breast cancer rates decreased when estrogen supplements stopped being given to menopausal women — these estrogen supplements were a main cause - There are very significant variations of cancer rates around the world In some areas, some cancers are more frequent than others suggests that environment influences the development of cancer When people migrate from one country to the other, they tend to take on the cancer patterns of their new domicile 23 of 66
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- 30-40% of cancers in the world, some 4 million cases a year, can be prevented by paying attention to environmental factors such a diet Five or more servings of fruit a day lowered the risk of prostate cancer by 50% 2,000 mg a day of calcium
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  • Spring '11
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