There are two major types of bacteria in digestive

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.
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Rodent studies have confirmed this
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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!!
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= bacteria has a role to play ONLY in the presence of a poor diet
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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 :
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Environment: 90%
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Diet and obesity: 30-35%
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Cancer is most frequent among those branches of the human race where
carnivorous habits prevails
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Tobacco: 25-30%
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Infections: 15-20%
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Radiation: 5-10%
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Pollution: 3-5%
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Alcohol/sexual: 3-5%
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Genetics: 5-10%
Study: environmental and heritable factors in causation of cancer (2000,
Scandinavia)
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45,000 pairs of twins studied
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10,000 cancers occurred
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Some cancers showed heritable factors
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Stomach cancer
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Environmental — Shared = 10% // Environmental — Non shared = 62%
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Heritable = 28%
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Cervical cancer
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Environmental: high
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Heritable: low
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Absolute risks (risks are averaged over a range)
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Monozygotic twins (identical): 15%
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Dizygotic twins (fraternal): 6%
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Conclusion:
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Unmistakable heredity: 1%
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Major component heredity: 15%
Another study on Norwegian Twins: heritability and familial risk of cancer (2013)
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Monozygotic and dizygotic pairs: 133,689
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Prostate cancer heritability (2013)= 58%, whereas prior study (2000) = 42%
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Other cancer rates lower and varied
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CONCLUSION : even with twins, environmental factors strongly
dominate
VIDEO 2
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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
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More than half a million people in the United States die of cancer every year
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About 1,500 Americans a day
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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
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Some cancers are falling and some are increasing, but the general cancer rate is
about the same
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Varies with location (environment and diets)
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Childhood cancer seems to be increasing, but we don’t know why
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Breast cancer rates decreased when estrogen supplements stopped being given to
menopausal women — these estrogen supplements were a main cause
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There are very significant variations of cancer rates around the world
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In some areas, some cancers are more frequent than others
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suggests that environment influences the development of cancer
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When people migrate from one country to the other, they tend to take on the
cancer patterns of their new domicile
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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
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Five or more servings of fruit a day lowered the risk of prostate cancer by 50%
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2,000 mg a day of calcium