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Evaluating Nutrition Information Chapter 2

Chapter Learning Outcomes 1.Define terms, including anecdote, variable, epidemiology, placebo, placebo effect, peer review, and quackery. 2.Understand the basis of the scientific method as it is used in developing hypotheses and conducting research in the field of nutrition. 3.Explain the importance of having controls when performing experiments. 4.Define research bias. 5.Describe how to identify questionable sources of nutrition information. 6.Identify reliable sources of nutrition information.

Quiz Yourself True or False Quiz Yourself True or False 1.Scientists generally do not raise questions about or criticize the conclusions of their colleagues’ research data, even when they disagree with those conclusions. T F 2.Popular health-related magazines typically publish articles that have been peer- reviewed. T F 

Quiz Yourself True or False (continued) Quiz Yourself True or False (continued) 3.By conducting a prospective epidemiological study, medical researchers can determine risk factors that influence health outcomes. T F 4.A placebo contains ingredients that provide no measurable effects. T F 5.In general, registered dietitians are reliable sources of food and nutrition information. T F 

How Did You Do? How Did You Do? 1.False Scientists generally do raise questions about or criticize the conclusions of their colleagues’ research data, even when they disagree with those conclusions. 2.False Popular health-related magazines typically publish articles that have not been peer-reviewed. 

How Did You Do? (continued) How Did You Do? (continued) 3.True By conducting a prospective epidemiological study, medical researchers can determine risk factors that influence health outcomes. 4.True A placebo contains ingredients that provide no measurable effects. 5.True In general, registered dietitians are reliable sources of food and nutrition information. 

Understanding the Scientific Method In the past, nutrition facts and dietary practices were based on: IntuitionIntuition Common senseCommon sense TraditionTradition AnecdotesAnecdotes Today, nutrition experts rely on the scientific method to base nutrition recommendations.

Scientific Method

Epidemiological Studies Epidemiology is the study of Disease rates among different population groupsDisease rates among different population groups Factors associated with disease occurrenceFactors associated with disease occurrence How diseases are spreadHow diseases are spread

Designing Epidemiological Studies Epidemiological studies are often:  Case-control — involves 2 groups; individuals are “matched”  Prospective — follows group of people into the future  Retrospective — examines the past to explain why some people are affected and not others

Correlations Correlations: Relationships between variables A correlation occurs when 2 variables change over the same period. Direct or positive relationship  regular soft drink intake   obesity Inverse or negative relationship  physical activity   obesity

Limitations of Epidemiological Studies Results could be a coincidenceResults could be a coincidence Cannot establish causationCannot establish causation Is the observation a cause, effect, or simply a Is the observation a cause, effect, or simply a coincidence? Difficulty in determining which variable is responsible for the conditionDifficulty in determining which variable is responsible for the condition Multiple factors, such as lifestyle, are often involved.

Experimentation In vitro “in test tube” testing on parts “in test tube” testing on parts of living organism, such as of living organism, such ascells In vivo testing on whole living testing on whole living organisms, such as lab rodents organisms, such as lab rodents

Basic Steps in Human Research Review scientific literatureReview scientific literature Develop a hypothesisDevelop a hypothesis Design study review human subjects research designDesign study — review human subjects research design Double-blind studies Conduct researchConduct research Analyze data, draw conclusions, report findingsAnalyze data, draw conclusions, report findings Follow up with more researchFollow up with more research

Example of an Experiment Involving Humans Example of an Experiment Involving Humans Study Group of 2000 Females 1000 Females 1000 Females Receive Treatment Control (Receive Placebo)     Measure and record changes then compare results of 2 groups

Peer Review Before acceptance for publication, research articles undergo critical analysis by peer experts in the field who were not part of the research team. Insert photo of journals from bottom of page 35

Quality Nutrition Research Is… Peer reviewedPeer reviewed Published in a respected nutrition-related journalPublished in a respected nutrition-related journal Reported at a nutrition or medical meetingReported at a nutrition or medical meeting If findings are simple and sensational, they may be reported as “sound bites” as TV and radio news features or in newspaper articles.

Why All the Confusion and Conflict? The science of nutrition is constantly evolving.The science of nutrition is constantly evolving. Old beliefs are discarded and advice changes as nutrition scientists conduct more research and gain greater understanding.Old beliefs are discarded and advice changes as nutrition scientists conduct more research and gain greater understanding.

Nutrition Information: Fact or Fiction Be skeptical of claims and ask questions…  What motivates the authors, promoters or sponsors?  Does the promoter/advertiser rely on anecdotes or testimonials?  Are there claims the product caused dramatic results?  Is the product touted as a new scientific breakthrough?

 Does the source of information have disclaimers? have disclaimers?  Is the source scientific?  If a study is cited, how was the research conducted? research conducted?  Does the source cite respected medical journals or mention reliable experts? reliable experts?  Are only benefits of using the product highlighted and harmful product highlighted and harmful side effects ignored? side effects ignored? More Questions…

Look for Red Flags for Unreliable Nutrition Information Look for Red Flags for Unreliable Nutrition Information Promises of quick and easy remedies Claims that sound too good to be true Scare tactics Attacks on conventional scientists and medical practitioners Statements about the superiority of natural dietary supplements Testimonials and anecdotes

Look for Red Flags (continued) Look for Red Flags (continued) Information that promotes a product’s benefits while overlooking its risks Vague, meaningless, or scientific-sounding terms Simplistic conclusions Sensational statements without citing references or sources Recommendations based on a single study

Look for Red Flags (continued) Look for Red Flags (continued) Information not supported by scientific evidence Sensational or frightening descriptions of commonly eaten foods References to natural cures Dramatic generalizations

Look for Red Flags (Continued) Look for Red Flags (Continued) Disclaimers, usually in small or difficult to read print

Tips for Searching Nutrition Information on the Internet Use multiple web sites, especially government sites.Use multiple web sites, especially government sites. Rely on sites reviewed or managed by health professionals.Rely on sites reviewed or managed by health professionals. Look for “HONcode” symbol.Look for “HONcode” symbol. Avoid sites that do not provide scientific sources.Avoid sites that do not provide scientific sources. Do not trust sites that attack scientific establishment.Do not trust sites that attack scientific establishment. Insert Figure 2.9

Tips for Searching Nutrition Information on the Internet (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 Health Information American Dietetic Association National Institutes of Health Food and Drug Administration Centers for Disease Control and Prevention

More Websites with Reliable Nutrition and Health Information (continued) American Council on Science and Health Quackwatch National Council Against Health Fraud

Why Consult Registered Dietitians? College-trained professionals College-trained professionals Have extensive knowledge in foods, nutrition, and dietetics Have extensive knowledge in foods, nutrition, and dieteticsCredentials: In the United States, look for “R.D.” In the United States, look for “R.D.” In Canada, look for “R.D., P.Dt., or R.Dt.”

Have You Considered Becoming a Dietitian? Professional divisions: Clinical dietetics Community nutrition Food service systems management Steps to become a dietitian: 1. Complete accredited baccalaureate degree program: coordinated program or didactic program 2. If necessary, complete supervised professional practice experience (“internship”) 3. 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