ACS Guidelines on Nutrition and Physical Activity for Cancer PreventionAmerican Cancer Society Guidelineson Nutrition and Physical Activity forCancer Prevention: Reducing the Risk of Cancer with Healthy FoodChoices and Physical ActivityDr. Byers is Professor,PreventiveMedicine,University of ColoradoHealth Science Center,Denver,CO.Dr. Nestle is Professor and Chair,Department of Nutrition and FoodStudies,New York University,NewYork,NY.Dr. McTiernan is AssociateMember,Fred Hutchinson CancerResearch Center,Seattle,WA.Ms. Doyle is Director,Nutrition andPhysical Activity,American CancerSociety,Atlanta,GA.Ms. Currie-Williams is Manager,utrition and Physical Activity,American Cancer Society,Atlanta,GA.Dr. Gansler is Director of MedicalStrategies,American CancerSociety,Atlanta,GA,and Editor of CA.Dr. Thun is Vice President,Epidemiology and SurveillanceResearch,American Cancer Society,Atlanta,GA.The following report was approvedby the American Cancer SocietyNational Board of Directors onNovember 1,2001.This article is also available online atwww.cancer.org.Tim Byers,MD,MPH;Marion Nestle,PhD,MPH;Anne McTiernan,MD,PhD;Colleen Doyle,MS,RD;Alexis Currie-Williams,MPH,CHES;Ted Gansler,MD;Michael Thun,MD;and the American Cancer Society 2001 Nutrition and Physical ActivityGuidelines Advisory Committee*ABSTRACT The American Cancer Society (ACS) has set aggressive challenge goals for thenation to decrease cancer incidence and mortality—and to improve the quality of life of cancersurvivors—by the year 2015. To address these critical goals, the ACS publishes the Nutrition and Physical ActivityGuidelines to serve as a foundation for its communication, policy, and community strategiesand ultimately, to affect dietary and physical activity patterns among Americans. These guidelines, published every five years, are developed by a national panel of expertsin cancer research, prevention, epidemiology, public health, and policy, and as such, theyrepresent the most current scientific evidence related to dietary and activity patterns andcancer risk.The American Cancer Society guidelines include recommendations for individual choicesregarding diet and physical activity patterns, but those choices occur within a communitycontext that either facilitates or interferes with healthy behaviors. Therefore, this committeepresents one key recommendation for community action to accompany the fourrecommendations for individual choices for nutrition and physical activity to reduce cancerrisk. This recommendation for community action underscores just how important communitymeasures are to the support of healthy behaviors by means of increasing access to healthfulfood choices and opportunities to be physically active.The ACS guidelines are consistent with guidelines from the American Heart Association forthe prevention of coronary heart disease as well as for general health promotion, as definedby the Department of Health and Human Services’ 2000 Dietary Guidelines for Americans.1,2(CA Cancer J Clin 2002;52:92-119.)*See pages 104 and 105.92CAA Cancer Journal for Clinicians CA Cancer J Clin 2002;52:92-119INTRODUCTIONThe Importance of Diet and Physical Activity inCancer PreventionFor the great majority of Americans who donot smoke cigarettes,dietary choices andphysical activity are the most importantmodifiable determinants of cancer risk.3Evidence suggests that one third of the morethan 500,000 cancer deaths that occur in theUnited States each year can be attributed todiet and physical activity habits,with anotherthird due to cigarette smoking.Althoughgenetic inheritance influences the risk ofcancer,and cancer arises from geneticmutations in cells,most of the variation incancer risk across populations and amongindividuals is due to factors that are notinherited.Behavioral factors such as smokingcigarettes,consuming foods along certainpatterns of diet,and staying active across thelifespan can substantially affect one’s risk ofdeveloping cancer.4,5,6Because healthfulindividual behaviors are most effectivelyenabled by social and environmental supportwithin communities,these 2001 guidelinesinclude,for the first time,an explicitrecommendation for community action.OVERVIEW OF THE GUIDELINESThe American Cancer Society publishesnutrition and physical activity guidelines toadvise health care professionals and the generalpublic about dietary and other lifestylepractices that reduce cancer risk.7Theseguidelines,updated in 2001 by the AmericanCancer Society Nutrition and Physical ActivityGuidelines Advisory Committee,are based onexisting scientific evidence that relates diet andphysical activity to cancer risk in humanpopulation studies as well as in laboratoryexperiments.These guidelines reflect the current state ofthe scientific evidence.For many issues,theevidence is not definitive either because studiesare not yet available,or current findings areinconsistent.Although the randomized,controlled trial is often considered the goldstandard for scientific conclusions,suchevidence is not presently available—and maynever become available—for many dietaryfactors associated with cancer risk.Inferencesabout the many complex interrelationshipsamong diet,physical activity,and cancer riskare based,for the most part,on observationalstudies coupled with advancing understandingof the biology of cancer.The relative strengthof current scientific evidence linking majorcomponents of diet to common cancer sites issummarized later in Table 5.In considering thetotality of evidence from a variety of sources,these guidelines take into consideration boththe benefits to cancer risk reduction andoverall health benefits.Although no diet canguarantee full protection against any disease,these guidelines offer the best informationcurrently available about how diet and physicalactivity can reduce the risk of cancer.The ACSguidelines are consistent with guidelines fromthe American Heart Association for theprevention of coronary heart disease as well asfor general health promotion,as defined by theDepartment of Health and Human Services’2000 Dietary Guidelines for Americans.1,2The American Cancer Society guidelinesinclude recommendations for individualchoices regarding diet and physical activitypatterns,but those choices occur within acommunity context that either facilitates orinterferes with healthy behaviors.Therefore,this committee presents one keyrecommendation for community action toaccompany the four recommendations forindividual choices for nutrition and physicalactivity to reduce cancer risk (Table 1).Thisrecommendation for community actionunderscores the importance of communityVolume 52 ? 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March/April 200293ACS Guidelines on Nutrition and Physical Activity for Cancer PreventionTABLE 1American Cancer Society (ACS) Guidelines on Nutrition and Physical Activity for Cancer PreventionACS Recommendations for Individual Choices1.Eat a variety of healthful foods,with an emphasis on plant sources.????Eat five or more servings of a variety of vegetables and fruits each day.Choose whole grains in preference to processed (refined) grains and sugars.Limit consumption of red meats,especially those high in fat and processed.Choose foods that help maintain a healthful weight.2.Adopt a physically active lifestyle.?Adults:engage in at least moderate activity for 30 minutes or more on five or more days of the week; 45 minutes or moreof moderate-to-vigorous activity on five or more days per week may further enhance reductions in the risk of breast andcolon cancer.?Children and adolescents:engage in at least 60 minutes per day of moderate-to-vigorous physical activity at least five days per week.3.Maintain a healthful weight throughout life.?Balance caloric intake with physical activity.?Lose weight if currently overweight or obese.4.If you drink alcoholic beverages,limit consumption.ACS Recommendation for Community ActionPublic,private,and community organizations should work to create social and physical environments that support the adoptionand maintenance of healthful nutrition and physical activity behaviors.?Increase access to healthful foods in schools,worksites,and communities.?Provide safe,enjoyable,and accessible environments for physical activity in schools,and for transportation and recreation in communities.measures to support healthy behaviors byincreasing access to healthful food choices andopportunities to be physically active.AMERICAN CANCER SOCIETY GUIDELINES FORNUTRITION AND PHYSICAL ACTIVITYRecommendation for Community ActionSocial,economic,and cultural factorsstrongly influence individual choices aboutdiet and physical activity.While mostAmericans would like to adopt a healthfullifestyle,many encounter substantial barriersthat make it difficult to follow diet and activityguidelines.Indeed,current trends towardincreasing consumption of high-calorieconvenience foods and restaurant meals,anddeclining levels of physical activity arecontributing to an alarming epidemic ofobesity among Americans of all ages and acrossall population segments.2Longer workdays andmore households with multiple wage earnersreduce the amount of time available forpreparation of meals,with a resulting shifttoward increased consumption of food outsidethe home—often processed foods,fast foods,and snack foods.Reduced leisure time,increased reliance on automobiles for94CAA Cancer Journal for Clinicians CA Cancer J Clin 2002;52:92-119transportation,and increased availability ofelectronic entertainment and communicationsmedia all contribute to a less active andincreasingly sedentary lifestyle.These trends areof particular concern,especially with regard tothe adverse effects they have on the long-termhealth of children,who are establishing lifetimepatterns of diet and physical activity,as well ason the poor,who live in communities with lessaccess to safe and healthful lifestyle options.Facilitating improved diet and increasedphysical activity patterns will require multiplestrategies,ranging from the implementation ofcommunity and work-site health promotionprograms to policies that affect communityplanning,transportation,school-based physicaleducation,and food services.Particular effortswill be needed to ensure that all populationgroups have access to healthful food choicesand opportunities for physical activity.Bothpublic and private organizations at the local,state,and national levels will have to developnew policies and will need to raise or reallocateresources to facilitate needed changes.Healthcare professionals,who can be especiallypersuasive on matters of lifestyle change,canprovide leadership in promoting policychanges in their communities.The decline in cigarette use by adultsprovides a useful analogy for the power of socialcontext in changing health behaviors.Adult-per-capita cigarette consumption began asustained decline after the 1964 SurgeonGeneral’s Report,which publicized the healthhazards of smoking.6From that time on,othercommunity-wide social and political factorshave become increasingly important in reducingsmoking.These include public policy changesregulating cigarette advertising,restrictingminors’access to tobacco products,increasingtaxation of tobacco products,and addressingconcerns about rights of nonsmokers,andexposure to second-hand smoke.Establishinghealthful patterns of diet and physical activitywill require similar purposeful changes inindividual lifestyle choices and in public policy.Public,private,and community organizationsshould strive to create social and physicalenvironments that support the adoption andmaintenance of healthful dietary and physicalactivity behavior patterns.Recommendations for Individual ChoicesThere is strong scientific evidence thathealthful dietary patterns,in combination withregular physical activity,can reduce cancerrisk.4,5Approximately 35 percent of cancerdeaths in the United States may be avoidablethrough dietary modification.8,9,10,11Thescientific study of nutrition and cancer ishighly complex,and many important questionsremain unanswered.It is not presently clear how single nutrients,combinations ofnutrients,overnutrition and energy imbalance,or the amount and distribution of body fat at particular stages of life affect one’s risk ofspecific cancers.However,epidemiologicalstudies have shown that populations whosediets are high in vegetables and fruits and lowin animal fat,meat,and/or calories have areduced risk of some of the most commontypes of cancer.Until more is known about thespecific components of diet that influencecancer risk,the best advice is to emphasizewhole foods and certain broad dietary patterns,as described within these guidelines.1.Eat a variety of healthful foods,with anemphasis on plant sources.Eat five or more servings of a variety ofvegetables and fruits each day.?Include vegetables and fruits at everymeal and for snacks.?Eat a variety of vegetables and fruits.?Limit French fries,snack chips,and otherfried vegetable products.?Choose 100% juice if you drink fruit orvegetable juices.Volume 52 ? 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March/April 200295ACS Guidelines on Nutrition and Physical Activity for Cancer PreventionChoose whole grains in preference toprocessed (refined) grains and sugars.?Choose whole grain rice,bread,pasta,and cereals.?Limit consumption of refinedcarbohydrates,including pastries,sweetened cereals,soft drinks,and sugars.Limit consumption of red meats,especiallythose high in fat and processed.?Choose fish,poultry,or beans as analternative to beef,pork,and lamb.?When you eat meat,select lean cuts andhave smaller portions.?Prepare meat by baking,broiling,orpoaching rather than by frying orcharbroiling.Choose foods that help you maintain ahealthful weight.?When you eat away from home,choosefoods that are low in fat,calories,andsugar,and avoid large portion sizes.?Eat smaller portions of high-caloriefoods.Be aware that “low-fat”or“nonfat”does not mean “low-calorie,”and that low-fat cakes,cookies,andsimilar foods are often high in calories.?Substitute vegetables,fruits,and otherlow-calorie foods for calorie-dense foodssuch as French fries,cheeseburgers,pizza,ice cream,doughnuts,and other sweets.Beneficial Effects of Vegetables and FruitsGreater consumption of vegetables,fruits,orboth together has been associated in themajority of epidemiological studies with alower risk of lung,oral,esophageal,stomach,and colon cancer.Evidence is less strong forcancers considered hormonal,such as breastand prostate.Diet can be an important factoreven in cancers caused,in large part,by otherfactors.For instance,many studies have found alower risk of lung cancer among those who eatmore vegetables and/or fruits in theirdiet.12,13,14,15Although the major factor thatcauses lung cancer is tobacco smoking,diet alsomodifies risk,both in smokers and in lifelongnonsmokers.Evidence that vegetable and fruitconsumption reduces cancer risk has led toattempts to isolate specific nutrients and toadminister these in pharmacological doses tohigh-risk populations.Most of these attemptshave been unsuccessful in preventing cancer orits precursor lesions,and in some cases,havehad adverse effects.Notable examples are thethree randomized trials of beta-carotene forthe prevention of lung cancer,initiated becauseof many observational epidemiological studiesindicating lower risk of lung cancer in personseating foods high in beta-carotene.Two of theclinical trials showed that smokers taking high-dose beta-carotene supplements developedlung cancer at higher rates than those taking aplacebo,14,15while a third study showed noeffect.16These findings support the idea thatbeta-carotene may be only a proxy for othersingle nutrients or combinations of nutrientsfound in whole foods,and that taking a singlenutrient in large amounts may be harmful.It is presently unclear which components ofvegtetables and fruits are most protectiveagainst cancer.17Vegetables and fruits arecomplex foods,each containing more than 100potentially beneficial vitamins,minerals,fiber,and other substances that may help to preventcancer.Vegetables and fruits also containspecific phytochemicals,such as carotenoids,flavonoids,terpenes,sterols,indoles,andphenols that show benefit against certaincancers in experimental studies.There isongoing research,for example,on the potentialbenefits of green and dark yellow vegetables,plants related to the cabbage family,soyproducts,legumes,allium (onion and garlic),and tomato products.Until more is known96CAA Cancer Journal for Clinicians
美国癌症协会预防癌症营养和体育活动指南((英文版)
