Diet, nutrition and the prevention of cancer,ppt

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  • Chinese-style salted fish is a special product which is usually softened by partial decomposition before or during salting; other types of salted fish have been studied and not found to be convincingly associated with the risk for developing nasopharyngeal cancer22
  • Attaining definitive evidence to confirm or refute effects of specific dietary factors on risks of human cancers is challenging and for many relationships may be impossible
  • Attaining definitive evidence to confirm or refute effects of specific dietary factors on risks of human cancers is challenging and for many relationships may be impossible
  • Food contaminated with aflatoxin convincingly increases the risk of liver cancerHigh intake of Chinese-style salted fish, increases the risk of nasopharyngeal cancer.
  • Diet, nutrition and the prevention of cancer,ppt

    1. 1. Group: 4Prepared by:Ashmita SharmaArati KuwarPurnima TimilsinaRajiv NepalIndra AcharyaTika Bdr. Thapa1
    2. 2. Chronic Diseases• Chronic diseases are diseases of long durationand generally of slow progression.• Chronic diseases, such as heart disease, stroke,cancer, chronic respiratory diseases and diabetes,are by far the leading cause of mortality in theworld, representing 63% of all deaths.• Out of the 36 million people who died fromchronic disease in 2008, nine million were under60 and ninety per cent of these premature deathsoccurred in low- and middle-income countries.2
    3. 3. Diabetes• Diabetes is a chronic disease that occurs eitherwhen the pancreas does not produce enoughinsulin or when the body cannot effectively usethe insulin it produces.• Insulin is a hormone that regulates blood sugar.Hyperglycaemia, or raised blood sugar, is acommon effect of uncontrolled diabetes and overtime leads to serious damage to many of thebodys systems, especially the nerves and bloodvessels.3
    4. 4. • 347 million people worldwide have diabetes.• In 2004, an estimated 3.4 million people diedfrom consequences of high fasting blood sugar.• More than 80% of diabetes deaths occur in low-and middle-income countries .• WHO projects that diabetes will be the 7thleading cause of death in 2030.• Healthy diet, regular physical activity, maintaininga normal body weight and avoiding tobacco usecan prevent or delay the onset of type 2 diabetes.4
    5. 5. Type 1 diabetes• Type 1 diabetes (previously known as insulin-dependent, juvenile or childhood-onset) ischaracterized by deficient insulin production andrequires daily administration of insulin.• Symptoms include excessive excretion of urine(polyuria), thirst (polydipsia), constanthunger, weight loss, vision changes and fatigue.These symptoms may occur suddenly.5
    6. 6. Type 2 diabetes• Type 2 diabetes (formerly called non-insulin-dependent or adult-onset) results from thebody’s ineffective use of insulin.• Type 2 diabetes comprises 90% of people withdiabetes around the world , and is largely theresult of excess body weight and physicalinactivity.6
    7. 7. Gestational diabetes• Gestational diabetes is hyperglycaemia withonset or first recognition during pregnancy.• Symptoms of gestational diabetes are similar toType 2 diabetes. Gestational diabetes is mostoften diagnosed through prenatalscreening, rather than reported symptoms.7
    8. 8. Cancer• Cancer is a generic term for a large group ofdiseases that can affect any part of the body.• Other terms used are malignant tumours andneoplasms.• This process is referred to as metastasis.Metastases are the major cause of death fromcancer.8
    9. 9. Cancer is a leading cause of death worldwide andaccounted for 7.6 million deaths (around 13% ofall deaths) in 2008. The main types of cancer are:• lung (1.37 million deaths)• stomach (736 000 deaths)• liver (695 000 deaths)• colorectal (608 000 deaths)• breast (458 000 deaths)• cervical cancer (275 000 deaths)• About 70% of all cancer deaths occurred in low-and middle-income countries. Deaths fromcancer worldwide are projected to continue torise to over 13.1 million in 2030.9
    10. 10. • Cancer causing viral infections such as HBV/HCVand HPV are responsible for up to 20% of cancerdeaths in low- and middle-income countries.• About 70% of all cancer deaths in 2008 occurredin low- and middle-income countries.• Deaths from cancer worldwide are projected tocontinue rising, with an estimated 13.1 milliondeaths in 2030.10
    11. 11. Cardio Vascular Diseases• Cardiovascular diseases (CVDs) are a group ofdisorders of the heart and blood vessels andthey include:• coronary heart disease,• cerebrovascular disease,• peripheral arterial disease• rheumatic heart disease,11
    12. 12. • congenital heart disease,• deep vein thrombosis and pulmonaryembolism,• Heart attacks and strokes are usually acuteevents and are mainly caused by a blockagethat prevents blood from flowing to the heartor brain.12
    13. 13. • An estimated 17.3 million people died from CVDsin 2008, representing 30% of all global deaths. Ofthese deaths, an estimated 7.3 million were dueto coronary heart disease and 6.2 million weredue to stroke .• Low- and middle-income countries aredisproportionally affected: over 80% of CVDdeaths take place in low- and middle-incomecountries and occur almost equally in men andwomen .13
    14. 14. • Most cardiovascular diseases can beprevented by addressing risk factors such astobacco use, unhealthy diet andobesity, physical inactivity, high bloodpressure, diabetes and raised lipids.• 9.4 million deaths each year, or 16.5% of alldeaths can be attributed to high bloodpressure. This includes 51% of deaths due tostrokes and 45% of deaths due to coronaryheart disease.14
    15. 15. OSTEOPOROSIS• Osteoporosis is defined as a progressive systemicskeletal disorder characterized by low bonemineral density (BMD), deterioration of themicroarchitecture of bone tissue, andsusceptibility to fracture.15
    16. 16. Types of osteoporosisOsteoporosis can be subdivided into 3 types:(1) involutional, or primary, osteoporosis in whichno underlying cause can be identified;(2) secondary osteoporosis in which the underlyingcause (eg, steroid use) is known; and(3) rare forms of the disease, such asjuvenile, pregnancy-related, and postpartumosteoporosis.16
    17. 17. Overweight and obesity• Overweight and obesity are defined as abnormalor excessive fat accumulation that presents a riskto health.• A crude population measure of obesity is thebody mass index (BMI).• A person with a BMI of 30 or more is generallyconsidered obese. A person with a BMI equal toor more than 25 is considered overweight.17
    18. 18. • Worldwide obesity has nearly doubled since1980.• In 2008, more than 1.4 billion adults, 20 andolder, were overweight. Of these over 200 millionmen and nearly 300 million women were obese.• 35% of adults aged 20 and over were overweightin 2008, and 11% were obese.• 65% of the worlds population live in countrieswhere overweight and obesity kills more peoplethan underweight.• More than 40 million children under the age offive were overweight in 2011.18
    19. 19. Refrences• 1) Danaei G, Finucane MM, Lu Y, Singh GM, CowanMJ, Paciorek CJ et al. National, regional, and globaltrends in fasting plasma glucose and diabetesprevalence since 1980: systematic analysis of healthexamination surveys and epidemiological studies with370 country-years and 2.7 millionparticipants. Lancet, 2011, 378(9785):31–40.(2) Global health risks. Mortality and burden of diseaseattributable to selected major risks. Geneva, WorldHealth Organization, 2009.(3) Mathers CD, Loncar D. Projections of globalmortality and burden of disease from 2002 to2030. PLoS Med, 2006, 3(11):e442.(4) Global status report on noncommunicable diseases2010. Geneva, World Health Organization, 2011.19
    20. 20. Diet, nutrition and the prevention ofcancer20
    21. 21. Abstract• Objective: To assess the epidemiologicalevidence on diet and cancer and make publichealth recommendations.• Design: Review of publishedstudies, concentrating on recent systematicreviews, meta-analyses and large prospectivestudies.21
    22. 22. Review• Dietary factors have been thought to accountfor about 30% of cancers in Westerncountries1, making diet second only totobacco as a preventable cause of cancer.• Then contribution of diet to cancer risk indeveloping countries has been considered tobe lower, perhaps around 20%2.22
    23. 23. International comparisons, migrants and timetrends• It was noted that developed Westerncountries have diets high in animalproducts, fat and sugar, and high rates ofcancers of the colorectum, breast andprostate.• In contrast, developing countries typicallyhave diets based on one or two starchy staplefoods, low intakes of animal products, fat andsugar, low rates of these ‘Western’cancers, and sometimes high rates of othertypes of cancer such ascancers of the 23
    24. 24. • Studies have shown that cancer rates oftenchange in populations which migrate from onecountry to another, and change over timewithin countries.• However, the international variations in dietand cancer rates continue to suggest that dietis an important risk factor for many commoncancers, and therefore that cancer may bepartly preventable by dietary changes.24
    25. 25. 25
    26. 26. Review of the role of diet in the aetiology of themajor cancers• Cancers of the oral cavity, pharynx andoesophagus:• In developed countries, the main risk factors arealcohol and tobacco, and up to 75% of thesecancers are attributable to these two lifestylefactors .• The mechanism of the effect of alcohol on thesecancers is not known, but may involve directeffects on the epithelium.• Overweight/obesity is an established risk factorspecifically for adenocarcinoma (but notsquamous cell carcinoma) of the oesophagus.26
    27. 27. • In developing countries, around 60% ofcancers of the oral cavity, pharynx andoesophagus are thought to be due tomicronutrient deficiencies.• The relative roles of various micronutrientsare not yet clear, but deficiencies ofriboflavin, folate, vitamin C and zinc may all beimportant.• Consistent evidence that consuming drinksand foods at a very high temperatureincreases the risk for these cancers.27
    28. 28. Nasopharyngeal cancer• consistently associated with a high intake ofChinese style salted fish, especially duringearly childhood as well as with infection withthe Epstein–Barr virus.Colorectal cancer• The best established dietary-related risk factoris overweight/ obesity.• Alcohol probably causes a small increase inrisk.• Adult height is weakly associated withincreased risk, and physical activity has beenconsistently associated with a reduced risk.28
    29. 29. Stomach cancer• Risk is increased by high intakes of some traditionallypreserved salted foods, especially meats and picklesand that risk is decreased by high intakes of fruits andvegetables perhaps due to their vitamin C content.Breast cancer• Much of this international variation is due todifferences in established reproductive risk factors suchas age at menarche, parity and age at births, andbreastfeeding, but differences in dietary habits andphysical activity may also contribute.• Oestradiol and perhaps other hormones play a key rolein the aetiology of breast cancer.29
    30. 30. Cancer of the liver• The major risk factor for hepatocellularcarcinoma is chronic infection with hepatitisB, and to a lesser extent, hepatitis C virus.• Ingestion of foods contaminated with themycotoxin aflatoxinis an important risk factoramong people in developing countries withactive hepatitis virus infection.• Excessive alcohol consumption is the maindiet-related risk factor for liver cancer.30
    31. 31. Cancer of the pancreas• Overweight/obesity possibly increases therisk.• Some studies have suggested that risk isincreased by high intakes of meat, andreduced by high intakes of vegetables.Lung cancerHeavy smoking ,low dietary intake of vitaminA, lower intake of fruits, vegetables andrelated nutrients (such as b-carotene) thancontrols increases the risk.31
    32. 32. Cancer of the cervix• The major cause of cervical cancer is infectionwith certain subtypes of the humanpapillomavirus.• Fruits, vegetables and related nutrients such ascarotenoids and folate tend to be inverselyrelated with risk.Cancer of the ovary• Risk is reduced by high parity and by long-termuse of combined oral contraceptives.• Some studies have suggested that risk isincreased by high intakes of fat or dairyproducts, and reduced by high intakes ofvegetables. 32
    33. 33. Prostate cancer• Diets high in red meat, dairy products andanimal fat have frequently been implicated inthe development of prostate cancer,• Lycopene, primarily from tomatoes, has beenassociated with a reduced risk in someobservational studies.Bladder cancer• Smoking increases the risk for bladder cancer.• Studies suggest that high intakes of fruits andvegetables may reduce risk33
    34. 34. • Cancer of the endometrium• As with breast cancer, the effect of obesity inpostmenopausal women on the risk forendometrial cancer is probably mediated bythe increase in serum concentrations ofoestradiol.• Some case-control studies have suggestedthat diets high in fruits and vegetables mayreduce risk and that diets high in saturated ortotal fat may increase risk, but the data arelimited.34
    35. 35. Kidney cancer• Overweight/obesity is an established riskfactor for cancer of the kidney.• an increase in risk with high intakes of meatand dairy products and a reduced risk withhigh intakes of vegetables.35
    36. 36. Meat• International correlation studies show a strongassociation between per capita consumptionof meat and colorectal cancer mortality• In addition, high iron levels in the colon mayincrease the formation of mutagenic freeradicals.• high consumption of preserved and red meatprobably increases the risk for colorectalcancer.36
    37. 37. Fat• high fat intake may increase the levels of cytotoxic freefatty acids or secondary bile acids in the lumen of thelarge intestine and increases breast cancer risk.Folate• methyl-deplete diet (i.e. a diet low in folate andmethionine and high in alcohol) ,is associated with anincreased risk of colon cancer.• use of folic acid containing multiple vitaminsupplements has been associated with lower risk ofcolon cancer.• A diminished folate status may contribute tocarcinogenesis by alteration of gene expression andincreased DNA damageand chromosome breakage. 37
    38. 38. Fruits, vegetables and fibre• Fibre increases stool bulk and speeds thetransit of food through the colon, thus dilutingthe gut contents and perhaps reducing theabsorption of carcinogens by the colonicmucosa.• Many case-control studies of colorectal cancerhave observed moderately lower risk inassociation with high consumption of dietaryfibre, and/or fruits and vegetables but theresults of recent large prospective studieshave been inconsistent. 38
    39. 39. • the association with fruits and vegetables isprincipally due to an increase in risk at verylow levels of consumption or that high intakesof refined flour or sugar (rather than lowintakes of fibre) increase risk through chronichyperinsulinaemia or other mechanism.Calcium• Several observational studies have supportedthis hypothesis and two trials have suggestedthat supplemental calcium may have a modestprotective effect on the recurrence ofcolorectal adenomas.39
    40. 40. Overweight/obesityObesity increases breast cancer risk inpostmenopausal women by around50%, probably by increasing serumconcentrations of free oestradiol.Alcohol• The only other established dietary risk factor forbreast cancer is alcohol.• There is now a large amount of data from well-designed studies which consistently shows asmall increase in risk with increasingconsumption, with about a 7% increase in risk foran average of one alcoholic drink every day.40
    41. 41. Conclusions on the effects of diet oncancer risk• Strengths and weaknesses of the evidence• Attaining definitive evidence to confirm.• relationship tested in multiple randomisedtrials to achieve a clear conclusion.• uncertainty about the time in life and numberof years before diagnosis.• Practical problems with compliance in long-term studies.• Because dietary behaviours are oftenassociated with other aspects of lifestyle thatcould affect cancer risk41
    42. 42. Conclusions on the effects of diet oncancer riskStrengths and weaknesses of the evidence• Attaining definitive evidence to confirm.• relationship tested in multiple randomised trialsto achieve a clear conclusion.• uncertainty about the time in life and number ofyears before diagnosis.• Practical problems with compliance in long-termstudies.• Because dietary behaviours are often associatedwith other aspects of lifestyle that could affectcancer risk 42
    43. 43. • many dietary factors may not act in isolationand it may be their interaction with otherdietary, lifestyle and/or genetic factors thatmay alter cell growth and affect cancer risk.• due to potential confounding by the multitudeof lifestyle and other environmental factorsthat vary geographically.• case-control studies provided the largemajority of data on diet and cancer.• Concerns on methodological biases, related toboth the selection of study participants andthe recall of diet after the diagnosis of cancer,.43
    44. 44. Dietary factors which convincingly increaserisk• Overweight/obesity• Alcoholic beverages• Aflatoxin• Chinese-style salted fish44
    45. 45. Conclusions on dietary factors andcancer• Review on diet and cancer mortality, aboutone third of cancers have generally beenthought to be related to dietary factors.• After tobacco, overweight/obesity appears tobe the most important avoidable cause ofcancer in populations with Western patternsof cancer incidence.• Physical activity reduces the risk for colorectalcancer and probably reduces the risk forbreast cancer.45
    46. 46. • Public health policy with respect to nutrition andcancer should be based on the best availablescientific research.• Avoiding overweight/obesity, limiting alcoholintake and increasing physical activity will reducecancer risk, as will limiting consumption of Chinese-style salted fish and minimizing dietary exposure toaflatoxin in populations where these dietary factorsare important.• Risk will probably be decreased by increasing theaverage intake of fruits and vegetables, and bylimiting intake of preserved and red meat, saltpreserved foods and salt, and very hot drinks andfood. Public health policy should, therefore, befocussed on these factors.46
    47. 47. 47
    48. 48. Thank you48

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