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Chapter 2Chapter 2

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Evaluating Nutrition InformationEvaluating Nutrition Information

Chapter 2

Chapter Learning OutcomesChapter Learning Outcomes1.1. Define terms, including anecdote, variable, Define terms, including anecdote, variable,

epidemiology, placebo, placebo effect, peer epidemiology, placebo, placebo effect, peer review, and quackery.review, and quackery.

2.2. Understand the basis of the scientific method as Understand the basis of the scientific method as it is used in developing hypotheses and it is used in developing hypotheses and conducting research in the field of nutrition.conducting research in the field of nutrition.

3.3. Explain the importance of having controls when Explain the importance of having controls when performing experiments.performing experiments.

4.4. Define research bias.Define research bias.5.5. Describe how to identify questionable sources of Describe how to identify questionable sources of

nutrition information.nutrition information.6.6. Identify reliable sources of nutrition informationIdentify reliable sources of nutrition information..

Quiz YourselfQuiz Yourself True or FalseTrue or False

1.1. Scientists generally do not raise questions Scientists generally do not raise questions about or criticize the conclusions of their about or criticize the conclusions of their colleagues’ research data, even when they colleagues’ research data, even when they disagree with those conclusions. T Fdisagree with those conclusions. T F

2.2. Popular health-related magazines typically Popular health-related magazines typically publish articles that have been peer-publish articles that have been peer-reviewed. T Freviewed. T F

Quiz YourselfQuiz Yourself True or False (continued)True or False (continued)

3.3. By conducting a prospective epidemiological By conducting a prospective epidemiological study, medical researchers can determine study, medical researchers can determine risk factors that influence health outcomes. risk factors that influence health outcomes. T F T F

4.4. A placebo contains ingredients that provide A placebo contains ingredients that provide no measurable effects. T Fno measurable effects. T F

5.5. In general, registered dietitians are reliable In general, registered dietitians are reliable sources of food and nutrition information. sources of food and nutrition information.

T FT F

How Did You Do?How Did You Do?

1.1. FalseFalse Scientists generally Scientists generally do do raise raise questions about or criticize the conclusions questions about or criticize the conclusions of their colleagues’ research data, even of their colleagues’ research data, even when they disagree with those conclusions.when they disagree with those conclusions.

2.2. FalseFalse Popular health-related magazines Popular health-related magazines typically publish articles that have typically publish articles that have not not been been peer-reviewed.peer-reviewed.

How Did You Do? How Did You Do? (continued)(continued)

3.3. TrueTrue By conducting a prospective By conducting a prospective epidemiological study, medical researchers epidemiological study, medical researchers can determine risk factors that influence can determine risk factors that influence health outcomes.health outcomes.

4.4. TrueTrue A placebo contains ingredients that A placebo contains ingredients that provide no measurable effects.provide no measurable effects.

5.5. TrueTrue In general, registered dietitians are In general, registered dietitians are reliable sources of food and nutrition reliable sources of food and nutrition information.information.

Understanding the Scientific MethodUnderstanding the Scientific Method

In the past, nutrition facts and dietary In the past, nutrition facts and dietary practices were based on:practices were based on:

• IntuitionIntuition• Common senseCommon sense• TraditionTradition• AnecdotesAnecdotes

Today, nutrition experts rely on the Today, nutrition experts rely on the scientific scientific methodmethod to base nutrition recommendations. to base nutrition recommendations.

Scientific MethodScientific Method

Epidemiological StudiesEpidemiological Studies

Epidemiology is the study ofEpidemiology is the study of

• Disease rates among different Disease rates among different population groupspopulation groups

• Factors associated with disease Factors associated with disease occurrenceoccurrence

• How diseases are spread How diseases are spread

Designing Epidemiological StudiesDesigning Epidemiological StudiesEpidemiological studies are often:Epidemiological studies are often:

Case-controlCase-control — involves 2 groups; — involves 2 groups;individuals are “matched”individuals are “matched”

ProspectiveProspective — follows group of people — follows group of peopleinto the futureinto the future

RetrospectiveRetrospective — examines the past — examines the pastto explain why some peopleto explain why some peopleare affected and not othersare affected and not others

CorrelationsCorrelations

Correlations: Correlations: Relationships between Relationships between variables variables A correlation occurs when 2 variables change A correlation occurs when 2 variables change over the same period.over the same period.

Direct or positive relationshipDirect or positive relationship regular soft drink intake regular soft drink intake obesity obesity

Inverse or negative relationshipInverse or negative relationship physical activity physical activity obesity obesity

Limitations of Epidemiological Limitations of Epidemiological StudiesStudies

• Results could be a coincidence Results could be a coincidence

• Cannot establish Cannot establish causationcausation

Is the observation a Is the observation a causecause, , effecteffect, or simply a, or simply acoincidencecoincidence??

• Difficulty in determining which variable is responsible for Difficulty in determining which variable is responsible for the conditionthe condition

Multiple factorsMultiple factors, such as , such as lifestylelifestyle, are often involved., are often involved.

ExperimentationExperimentation

In vitroIn vitro ““in test tube” testing on partsin test tube” testing on parts of living organism, such asof living organism, such as

cellscells

In vivoIn vivo testing on whole livingtesting on whole living organisms, such as lab rodentsorganisms, such as lab rodents

Basic Steps in Human Research

• Review scientific literatureReview scientific literature• Develop a hypothesisDevelop a hypothesis• Design study Design study — review human subjects review human subjects

research designresearch designDouble-blind studiesDouble-blind studies

• Conduct researchConduct research• Analyze data, draw conclusions, report Analyze data, draw conclusions, report

findingsfindings• Follow up with more researchFollow up with more research

Example of an Experiment Example of an Experiment Involving HumansInvolving Humans

Study Group of 2000 Females Study Group of 2000 Females

1000 Females 1000 Females 1000 Females 1000 FemalesReceive Treatment Control (Receive Placebo)Receive Treatment Control (Receive Placebo)

Measure and record changes then

compare results of 2 groups

Peer ReviewPeer Review

Before acceptanceBefore acceptancefor publication,for publication,research articlesresearch articlesundergo criticalundergo criticalanalysis by peeranalysis by peerexperts in the fieldexperts in the fieldwho were not part ofwho were not part ofthe research team.the research team.

• Insert photo of journals from bottom of page 35

Quality Nutrition Research Is…Quality Nutrition Research Is…

• Peer reviewedPeer reviewed• Published in a respected nutrition-related Published in a respected nutrition-related

journaljournal• Reported at a nutrition or medical meetingReported at a nutrition or medical meeting

If findings are simple and sensational, they If findings are simple and sensational, they may be reported as “sound bites” as TV and may be reported as “sound bites” as TV and radio news features or in newspaper articles.radio news features or in newspaper articles.

Why All the Confusion and Why All the Confusion and Conflict?Conflict?

• The science of nutrition is constantly The science of nutrition is constantly evolving.evolving.

• Old beliefs are discarded and advice Old beliefs are discarded and advice changes as nutrition scientists conduct changes as nutrition scientists conduct more research and gain greater more research and gain greater understanding. understanding.

Nutrition Information: Fact or FictionNutrition Information: Fact or Fiction

Be skeptical of claims and ask questions…Be skeptical of claims and ask questions…

WWhat motivates the authors, promoters or sponsors?hat motivates the authors, promoters or sponsors?

DDoes the promoter/advertiser rely on anecdotes or oes the promoter/advertiser rely on anecdotes or testimonials?testimonials?

AAre there claims the product caused dramatic results? re there claims the product caused dramatic results?

IIs the product touted as a new scientific breakthrough?s the product touted as a new scientific breakthrough?

DDoes the source of information oes the source of information have disclaimers?have disclaimers? IIs the source scientific?s the source scientific? IIf a study is cited, how was thef a study is cited, how was the research conducted?research conducted? DDoes the source cite respected oes the source cite respected

medical journals or mentionmedical journals or mention reliable experts?reliable experts? AAre only benefits of using there only benefits of using the product highlighted and harmfulproduct highlighted and harmful side effects ignored?side effects ignored?

More Questions…More Questions…

Look for Red Flags Look for Red Flags for Unreliable Nutrition Informationfor Unreliable Nutrition Information

Promises of quick and easy remediesPromises of quick and easy remedies

Claims that sound too good to be trueClaims that sound too good to be true

Scare tacticsScare tactics

Attacks on conventional scientists and medical Attacks on conventional scientists and medical practitionerspractitioners

Statements about the superiority of natural Statements about the superiority of natural dietary supplementsdietary supplements

Testimonials and anecdotesTestimonials and anecdotes

Look for Red Flags Look for Red Flags (continued)(continued)

Information that promotes a product’s benefits Information that promotes a product’s benefits while overlooking its riskswhile overlooking its risks

Vague, meaningless, or scientific-sounding Vague, meaningless, or scientific-sounding termsterms

Simplistic conclusionsSimplistic conclusions

Sensational statements without citing Sensational statements without citing references or sourcesreferences or sources

Recommendations based on a single studyRecommendations based on a single study

Look for Red Flags Look for Red Flags (continued)(continued)

Information not supported by scientific evidenceInformation not supported by scientific evidence

Sensational or frightening descriptions of Sensational or frightening descriptions of commonly eaten foodscommonly eaten foods

References to natural curesReferences to natural cures

Dramatic generalizationsDramatic generalizations

Look for Red Flags Look for Red Flags (Continued)(Continued)

Disclaimers, Disclaimers, usually in small or usually in small or difficult to read difficult to read printprint

Tips for Searching Nutrition Tips for Searching Nutrition Information on the InternetInformation on the Internet

• Use multiple web sites, Use multiple web sites, especially government sites.especially government sites.

• Rely on sites reviewed or Rely on sites reviewed or managed by health managed by health professionals.professionals.

• Look for “HONcode” symbol.Look for “HONcode” symbol.

• Avoid sites that do not provide Avoid sites that do not provide scientific sources.scientific sources.

• Do not trust sites that attack Do not trust sites that attack scientific establishment.scientific establishment.

Insert Figure 2.9

Tips for Searching Nutrition Tips for Searching Nutrition Information on the Internet Information on the Internet

(continued)(continued)

• Avoid sites that provide online diagnoses or treatments.

• Be wary of commercial sites (*.com), even those with links to reliable sites.

• Avoid providing your personal information.

Websites with Reliable Nutrition and Websites with Reliable Nutrition and Health InformationHealth Information

American Dietetic Association American Dietetic Association http://www.eatright.org

National Institutes of Health National Institutes of Health http://www.nih.gov

Food and Drug Administration Food and Drug Administration http://www.fda.gov

Centers for Disease Control and Prevention Centers for Disease Control and Prevention http://www.cdc.gov

More Websites with Reliable Nutrition More Websites with Reliable Nutrition and Health Information and Health Information (continued)(continued)

American Council on Science and Health American Council on Science and Health http://www.acsh.org

Quackwatch Quackwatch

http://www.quackwatch.org

National Council Against Health Fraud National Council Against Health Fraud

http://www.ncahf.org

Why Consult Registered Dietitians?Why Consult Registered Dietitians?

College-trained professionals College-trained professionals

Have extensive knowledge in foods, nutrition, Have extensive knowledge in foods, nutrition, and dieteticsand dietetics

Credentials:Credentials:

In the United States, look for “In the United States, look for “R.DR.D.” .” www.eatright.org/find.html

In Canada, look for “R.D., P.Dt., or R.Dt.”In Canada, look for “R.D., P.Dt., or R.Dt.” www.dietitians.ca

Have You Considered Becoming a Have You Considered Becoming a Dietitian?Dietitian?

Professional divisions: Professional divisions: Clinical dieteticsClinical dieteticsCommunity nutritionCommunity nutritionFood service systems managementFood service systems management

Steps to become a dietitian:Steps to become a dietitian:1. Complete accredited baccalaureate degree 1. Complete accredited baccalaureate degree program: coordinated program or didactic program: coordinated program or didactic programprogram2. If necessary, complete supervised professional 2. If necessary, complete supervised professional practice experience (“internship”) practice experience (“internship”) 3. Pass the national registration examination3. Pass the national registration examination

What’s a “Supervised Professional Practice” Experience?

• Coordinated Program (CP) – Classroom instruction with > 900 hrs of supervised

practice under an RD

• Didactic Program in Dietetics (DPD) – Provides classroom instruction only – After graduation, students must apply for a dietetic

internship program that includes > 900 hrs of supervised practice