Diet and Cancer:

What Don’t We Know and When Didn’t We Know it?

Dileep G. Bal, M.D., ChiefCancer Control Branch

Department of Health Services

This presentation represents the opinions of

Dileep G. Bal, M.D.and not the California Department

of Health Services, in any way whatsoever. The opinions of either can change without further notice.

WRITTEN DISCLAIMER

Present the American Cancer Society Nutrition and Physical Activity Guidelines for Cancer Prevention

Discuss the science base behind the recommendations

Present current trends and statistics

Objectives Today

On any given dayin the United States...

815 billion caloriesare consumed (200 billion more than needed)

47 million hot dogs4 million pounds of bacon60 million pounds of red meat170 million eggs

On any given dayin the United States...

3 million gallons of ice cream

10 million pounds of candy

16 million gallons of beer and ale

1.5 million gallons of hard liquor(enough to make 26 million people drunk!)

WEDNESDAY, MAY 22, 1996

Thou Shalt Reduce Salt Intake:True? False? Choose Your Study

By GINA KOLATA

250

300

350

400

450

500

550

'73 '76 '79 '82 '85 '88 '91 '94 '97 '00 '03 '06 '09 '12 '15

Year

Rat

eAll Sites (Invasive) – Incidence RatesBy Year of Diagnosis – All Races, Males and Females

2015 Goal 383.4

406.7 If Trend Continues

1992 Baseline 511.2

1970 US Std. Population

Incidence and mortality rates per 100,000 and age-adjusted to 2000 US standard populationSEER Cancer Statistics Review 1973-1999.

1999 476.1

Average Decline 1.0% per Year Between 1992-1999If Trend Continues, 20% Reduction by 2015 Recent Trend Appears Level or Decreasing

( 6.9% from Baseline)

2000 US Std. Population

2015 Goals – 25% Reduction from Baseline

319.5

Incidence and mortality rates are per 100,000 and are age-adjusted to the 2000 U.S. standard population. SEER Cancer Statistics Review 1973 - 1999.

8090

100110120130140150160170180190200210220

'73 '76 '79 '82 '85 '88 '91 '94 '97 '00 '03 '06 '08 '11 '14

Year

Rat

eAll Sites – Mortality Rates By Year of Death – All Races, Males and Females

180.4 If Recent Trend Continues

1991 Baseline215.4 1999

202.8

1970 Std. Population

2000 Std. Population

Steeper Rate of Decrease, 1.4 % per Year, Beginning 1995 and Continuing through 1999If trend Continues - 16% Reduction by 2015Trend Continues

2015 Goals – 50% Reduction from Baseline

2015 Goal 107.7

86.7

( 5.9 % from Baseline)

Actual Causes of Deathin the United States (1990)

0 5 10 15 20Percent of all causes of death

TobaccoDiet/Activity

AlcoholMicrobial Agents

Toxic AgentsFirearms

Sexual BehaviorMotor Vehicles

Data Source: McGinnis & Foege, JAMA, November, 1993

Causes of CancerEstimate percentage of total cancer deaths attributable to established causes of cancer

TobaccoAdult diet/obesity

Sedentary lifestyleOccupational factors

Family history of cancerViruses/other biologic agents

Perinatal factors/growthReproductive factors

AlcoholSocioeconomic status

Environmental pollutionIonizing/ultraviolet radiation

Prescription drugsMedical procedures

Salt/other food additives or contaminants

Source: Harvard Report on Cancer Prevention, Cancer Causes and Control, November/December, 1996

0 5 10 15 20 25 30 35

Normal Cell

Cell with DNA abnormality

*

MUTATIONInheritedSpontaneousAcquired

Tumor

PROMOTIONPROGRESSION

Carcinogenesis

Hormones Growth factors

Energy Energy Intake Intake

(Carcinogen)(Carcinogen)

EnergyEnergyExpenditureExpenditure

((PhytochemicalsPhytochemicals) )

High Fat/Calories High Fat/Calories High High ωω --6 fats6 fats

Growth FactorsGrowth FactorsGeneticGenetic

SusceptibilitySusceptibility(Common Polymorphisms)(Common Polymorphisms)

Physical Activity Physical Activity FruitsFruits

VegetablesVegetablesWhole GrainsWhole GrainsSoy ProteinSoy Protein

Obesity,Nutrition,and CancerGene-Nutrient

Imbalance

To review current scientific data on diet and cancersTo translate this into clear, defensible recommendations for the general publicTo promote changes in environments that support healthful eating and physical activity habits To reduce cancer risk

Purpose of the Nutrition and Physical Activity Guidelines

Which year? (1)

“In England, four and a half times as many people die now from cancer as half a century ago. Probably no single factor is more important in determining the outbreak of cancer in the predisposed than high feeding. Many indications point to the gluttonous consumption of meat as likely to be especially harmful.

Which year? (2)

Statistics show that the consumption of meat has reached the amazing total of 131 pounds per head per year, which is more than double what it was half a century ago. No doubt other factors co-operate, among these I should be inclined to name deficient exercise and deficiency in fresh vegetable food.”

December, 1898!W. Roger Williams in The

Lancet

So, what didn’t we know and when didn’t we know it?

Society Recommendations

Eat a variety of foods, with anemphasis on plant sources.

Adopt a physically active lifestyle.

Maintain a healthful weight throughout life.

If you drink alcoholic beverages, limit consumption.

Individual Choices

Society Recommendations Community Action

Public, private, and community organizations should work to create social and physical environmentsthat support the adoption and maintenance of healthful nutrition and physical activity behaviors

Society Recommendations Community Action

Increase access to healthful foods in schools, worksites, and communities.

Provide safe, enjoyable, and accessibleenvironments for physical activity in schools, and for transportation and recreation in communities.

Society Recommendations

Eat a variety of healthful foods,with an emphasis on plant sources.

Eat 5 or more servings of a variety of vegetables and fruit 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.

Individual Choices

Include vegetables or fruits in every meal and for snacks.

Limit french fries, snack chips, and other fried vegetable products.

Choose 100% juice if you drink fruit or vegetable juices.

Eat five or more servings of a variety of vegetables and fruits each day

Why Fruits and Vegetables?

Mouth and pharynxOesophagusLungStomachColon, rectum*

Decreases Risk Convincing

Decreases Risk ProbableLarynxPancreasBreastBladder

Liver*OvaryEndometriumCervixProstate*ThyroidKidney*

Decreases Risk Possible

*Vegetables only

Food, Nutrition and the Prevention of Cancer: A Global Perspective American Institute for Cancer Research, 1997

Fruits and Vegetables and the Prevention of Cancer

Origins of the 5 a Day Campaign

1986 National Cancer Institute grant to the California Department of Health ServicesOriginal plan called for addressing fat, fruits and vegetables, and fiberPlan revised to focus on promoting 5 daily servings of fruits and vegetables because– strong science– win-win-win– feasibility

California 5 a Day Campaign

1988: California 5 a Day Campaign developed1988-1991: Campaignpromotions conducted1991: 5 A Day goes national

California 5 a Day Campaign Spinoffs

Children’s 5 a Day--Power Play! Campaign (1993)Latino 5 a Day Campaign (1994)Network 5 a Day Campaign for low-income families (1998)Women’s 5 a Day Campaign (1999)

RR = Relative Risk = Risk RatioRisk among exposed/Risk among non-exposedNull association, RR = 1.00RR of 1.5 means exposed group has 50% greater risk of disease than non-exposed; RR of 0.60 means 40% lower risk

Relative Risk What it means

Vegetables and Colorectal CancerProspective Cohort Studies

0 0.5 1 1.5 2Relative Risk

Steinmetz, 1994

Pietinen, 1999

Voorrips, 2000- Men

Voorrips, 2000-Women

Michels, 2000

Terry, 2001

Thun, 1992- Men

Thun, 1992- Women

.2

Lung cancer incidence associated withbeta-carotene treatment versus placebo

0

0.5

1

1.5

2

Currentsmoker

Neversmoker

Formersmoker

Currentsmoker

Formersmoker

Currentsmoker

RR

ATBC Physicians’ Health CARET

Percent of adults eating 5 or more fruits and vegetables per day, 1998

26.6 to 31.923.9 to 26.520.7 to 23.89.1 to 20.6Source: BRFSS, NCCDPHP, CDC, 2000

United States Median: 23.9

Include grain products such as breads, cereals rice, pasta, or beans in every meal.Eat other foods from plant sources several times each day.Limit consumption of refined carbohydrates, including pastries, sweetened cereals, soft drinks, and sugars.

Choose whole grains in preference to processed (refined) grains and sugars.

Whole grains & cancerProspective cohort studies

0 0.5 1 1.5 2Relative Risk

Thun, 1992-men*

Thun, 1992-women*

Jacobs, 1999-women

Jacobs, 2001

*colon cancer mortality; others = all cancers

Choose fish, poultry, or beans as an alternative to beef, pork, and lamb

When you eat meat, select lean cuts and smaller portions

Prepare meat by baking, broiling, poaching, rather than by frying or charbroiling

Limit consumption of red meats, especially those high in fat and processed

Red meat (1 portion)and colorectal cancer

Source: Sandhu MS et al. CEBP 2001;10:439- 446

Processed meat (1 portion)and colorectal cancer

Source: Sandhu MS et al. CEBP 2001;10:439- 446

Heterocyclic aminesCooking methodsFood safety

Current research about meat

Total fat?Type of fat?Calories from fat?Some other factor in the fat in foods?

What about fat?

Prevalence of Overweight among Prevalence of Overweight among U.S. Adults, BRFSS, 1985U.S. Adults, BRFSS, 1985

<10%<10% 1010--15%15% >15%>15%Source: Mokdad, et al.

<10%<10% 1010--15%15% >15%>15%

Prevalence of Overweight among Prevalence of Overweight among U.S. Adults, BRFSS, 1997U.S. Adults, BRFSS, 1997

Source: Mokdad, et al.

Choose foods that help maintain a healthful weight

When you eat away from home, choose foods low in fat, calories and sugar, and avoid large portion sizes.

Eat smaller portions of high calorie foods.

Substitute vegetables, fruits, and other low- calorie foods for calorie- dense foods such as French fries, cheeseburgers, pizza, ice cream, doughnuts and other sweets.

• active controversy of whether benefit is due to individual nutrients, whole foods or overall dietary pattern

• most evidence shows that people who have healthy diets have lower risk of many cancers

Nutrition & cancerresearch in early stages

“It is often necessary to make a decision on the

basis of information sufficient for action but insufficient to entirely satisfy the intellect.”

-Emmanuel Kant

Asymmetric Information

Exploring how people can make better decisions

despite incomplete information

The late William Vickery (Columbia University) and James Mirrlees

(Cambridge University) shared 1996 Nobel Prize in Economics

Society Recommendations

1. Adopt a physically active lifestyle.

Adults

Engage in at leastmoderate activity for 30 minutes or more on 5 or more days of the week

45 minutes or more of moderate to vigorous even more helpful for breast and colon cancer

Individual Choices

Society Recommendations

2. Adopt a physically active lifestyle.Children & Adolescents

Engage in at least 60 minutes per day of moderate- to- vigorous physical activityat least 5 days per week.

Individual Choices

Physical activity and cancer Summary of evidence

Cancer Studies Temporality StrengthColon 39/46 Throughout ConvincingBreast 24/36 Early & adult ConvincingProstate 15/26 Early life? ProbableLung 6/8 Unknown PossibleEndometrial 8/11 Unknown PossibleTesticular 3/8 Unknown InsufficientOvarian 2/5 Unknown Insufficient

Source: Friedenreich. CEBP 2001;10:287- 301

Physical activity and colorectal cancer

Source: Friedenreich. CEBP 2001;10:287- 301

Physical activity and breast cancer

Source: Friedenreich. CEBP 2001;10:287- 301

Participation in physical activity, adults, 1998(% regular and sustained physical activity)

24.1 to 30.320.4 to 24.018.6 to 20.313.0 to 18.5

Source: BRFSS, NCCDPHP, CDC, 2000

United States Median: 20.4

Adopt a physically active lifestyle

Emphasis on children and adolescents critically important.Increasing trends in overweight and obesity raise concerns about future cancer rates

Potential mechanisms for physical activity and cancer

May prevent overweight and obesity to protect against cancer

Colon, rectal, prostate, endometrial, breast (among postmenopausal women), and kidney

May act through hormones-Prostate and breast cancers

Energy metabolism

Strongest association with breast and colon cancers

ColonStimulates movement through the bowel, reducing the length of time bowel lining is exposed to mutagens

Breast cancer– Helps control weight– Decreases circulating hormones

Society Recommendations

3. Maintain a healthful weight throughout life.

Balance caloric intake with physical activity

Lose weight if currently overweight or obese

Individual Choices

The Spread of the Obesity Epidemic

*Obesity is defined as a BMI of 30 or greater. **States are white in years 1991 and 1993 because information on weight and height was not collected. *** The Healthy People 2010 Goal is to reduce the proportion of adults who are obese to less than 15% . Source: Behavioral Risk Factor Surveillance System, CD-ROM 1984-1995, 1998, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, 1997, 2000.

<10%

10- 15%

>15%

1991 1993

1995 1998

State Prevalence

0.60.81.01.21.41.61.82.02.22.4

<18.5

18.5-

20.4

20.5-

21.9

22.0-

23.4

23.5-

24.9

25.0-

26.4

26.5-

27.9

28.0-

29.9

30.0-

31.9

32.0-

34.9

35.0-

39.9

CardiovascularCancerAll other causes

Body- Mass IndexSource: Calle EE, et al. NEJM. 1999;341:1097-1105.

Rel

ativ

e R

isk

Body mass index and mortality in women

How obesity may cause cancer

Estrogen productionInsulin resistanceMechanicalOther

Society Recommendations

4. If you drink alcoholic beverages, limit consumption.

Individual Choices

If you drink alcoholic beverages, limit consumption.

Drink is 12 oz of regular beer, 5 oz of wine, 1.5 oz liquor

Moderate defined as no more than 2 drinks per day for men and 1 drink for women

Increases risk of:Mouth and esophageal cancersPharynx and larynx cancersLiver cancer Breast cancer in women

Combined use of alcohol and tobacco greatly increases risk compared to drinking or smoking alone

Alcohol and Cancer Risk

Effect of alcohol consumption and cigarettesmoking on oropharyngeal cancer incidence

Source: Blot WJ et al. Cancer Research 1988;48- 3282- 7

0

5

10

15

20

25

30

35

40

<1 1-4 5-14 15-29 30+Drinks per week

OR

Nonsmoker Short duration or former 1-19 cpd for 20+ years20-39 cpd for 20+ years 40 cpd for 20+ yrs

Men

0

20

40

60

80

100

120

<1 1-4 5-14 15-29 30+Drinks per week

OR

Women

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

None <1 1 2 3 4-5 6+

Drinks per day

RR

CPS-II Men - Risk of alcohol related diseases increases with drinks per day

Source: Thun MJ et al. NEJM 1997;337:1705- 1714

CPS-II Women - Risk of alcohol related diseases increases with drinks per day

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

None <1 1 2 3 4-5 6+

Drinks per day

RR

Source: Thun MJ et al. NEJM 1997;337:1705- 1714

Alcohol & Breast Cancer RiskRisk increases with an intake beginning at just a few drinks per week

Mechanism unknown– changes in hormones?– carcinogenic effect on breast

tissue?– lowers serum folate

Cutting back is a good way for women who drink regularly to reduce risk

“I thought a glass of wine was good for me!”

Moderate intake of alcohol appears to decrease risk of heart disease– Other approaches to reduce

heart disease riskNot recommended that non-drinkers begin drinkingConsider risk of both heart disease and cancer to make an informed decision

At this point in time…

Based on what we know right now…

To Reduce Your Risk of Colorectal Cancer

Increase intensity and duration of physical activity

Eat more vegetables, fruits and whole grains

Limit intake of red meats

Avoid obesity

Avoid tobacco use and excessive alcohol consumption

To Reduce Your Risk of Breast Cancer

Engage in vigorous physical activity at least 4 hours a week

Minimize lifetime weight gain through– Limiting calories– Regular physical activity

Limit intake of alcoholic beverages

Eat a variety of vegetables and fruits

To Reduce Your Risk of Prostate Cancer

Limit intake of foods from animal products, especially red meats and high fat dairy products

Eat a variety of vegetables and fruits daily (lycopene hypothesis)

Limited evidence on the benefits of– Vitamin E– Selenium

To Reduce Your Risk of Lung Cancer

Avoid tobacco use or exposure

Eat at least 5 servings of vegetables and fruits each day

What nutrients or combination of nutrients has an effect?

There is no controversy on whethernutrition and physical activity have an impact on cancer risk

When during the life cycle is there an effect? (or the greatest effect?)

How much/how little has an effect?

Creating Change

How can we get people to eat healthy and be more active?

A complex issue that requires a multi channel solution

From: Healthy People 2010, Understanding and Improving Health, Volume 1

Social Ecological Model

Interpersonal & Social Networks

Individual

Institutional/Organizational

Community

Social Structure, Policy

BasicBasicBiomedicalBiomedicalResearchResearch

StatewidePrevention

&Health

ServicesPrograms

StatewideStatewidePreventionPrevention

&&Health Health

ServicesServicesProgramsPrograms

VI. Intervention

Technology for Lifestyle Risk

Factors common to

other Chronic Diseases

VII. Institutionalization,

Technology Transfer, Program

Diffusion

V. Demonstration

& Implementation

of Benefitsin Large

Populations

II. Methods

DevelopmentIntervention

Tools Identified for Hypothesis

Testing

III. Controlled

Intervention Trials to test Intervention Hypothesis

IV. Defined

PopulationStudies

I. Hypothesis

Developmentfor Cancer

Control Strategies

The Theory Is Strong

IndividualInterpersonal

LifestyleInfluences

Institutional/Organizational

Community Social Structure,Policy, Systems

California Nutrition Network of Healthy Families Social-Ecological Model for Intervention and

Evaluation

Spheres of Influence

Research is wasted unless it is translated into action

and applied on main street across the land,

by involving the key public and private sector players.

How can we create change?Target Systems

• Schools• Worksites• Communities

Multi-level integrated interventionsEnvironment and Policy PartnershipsComprehensive coordinated communications efforts

Nutrition vs. Tobacco

Can get to relatively low risk in about 5 years vs. 15-20 years for tobaccoLess than 17% of Californians smoke; everybody eatsEach responsible for 1/3 of cancersTobacco is an addictive substance

Can get to relatively low risk in about 5 years vs. 15-20 years for tobaccoLess than 17% of Californians smoke; everybody eatsEach responsible for 1/3 of cancersTobacco is an addictive substance

Social Transformation Requires:

· A crisis · Science base

· “Spark plugs”, champions · Advocacy

· An economic imperative, and solutions

· Coalition development

· Government involvement at multiple levels

· Mass communications, including media advocacy

· Environmental and policy change—more than education

· A plan, so pieces work synergistically, at multiple levels, in multiple sectors

Source: Tufts, National Partnership for Healthy Eating and Active Living, 2000

But Is There the Technical and Political Will? New Directions for Research---

Beyond the Basics and Across Disciplines· Who wins, loses with healthy eating and exercise?· What are the incentives/disincentives of different

marketplace sectors?· Where we don’t know, what do different consumer

segments want/need?· What interventions do key intermediaries want to offer?· For policy change, what does the public want?

What do policy makers think?· What are the most rational funding sources?· Who are the coalition members, and how much muscle

will they flex? · Do “town and gown” have the will to make change?

Will researchers join forces with public health and the advocates?