1. Evaluating Nutrition Information
Chapter 2
Evaluating Nutrition Information
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2. Introduction
Early 1900’s the disease pellagra was widely spread in southern states.
Symptoms:
diarrhea
skin rash
mental confusion
Seen in prisons, orphanages, and mental health institutions
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3. Introduction
Initially people believed it was an infectious disease. But in 1914 Dr. J Goldberger suggested that diet played a role because all those effected had a diet of:
Corn Bread
Hominy grits
Molasses
Potatoes
Cabbage
Rice
***Higher income individuals also ate things like meat, milk, and fresh vegetables!***
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4. Introduction
Tested his hypothesis by adding missing nutritents to diet and saw complete remission of symptoms…still wasn’t supported.
Did a “filth party” swabbed nose and throats of sick people and then applied them to healthy people…Result: no disease transfer!...No one believed him!
Wasn’t until 1937 (8 yrs after Goldberger’s death) that another scientist (Elvehjem) discovered niocin (vitamin) in liver extract.
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5. Introduction
More recent example of a medical hypothesis involved stomach ulcers
Warren and Marshall in 1982 hypothesized it was not stress but bacteria that caused ulcers after isolating the bacteria Helicobacter pylori from patients
No one believed them they believed bland diet and antacids were the only treatment while W&M were suggesting antibiotics!
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6. Helicobacter pylori
To prove it Marshall actually ingested the bacteria and proved it by developing ulcers.
They were awarded the Nobel Prize in Medicine in 2005
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7. 2.1 Understanding the Scientific Method
In the past, nutrition facts and dietary practices were based on:
Intuition
Common sense
“Conventional wisdom”
Anecdotes
Today, nutrition experts rely on the scientific method to base nutrition recommendations.
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8. Today nutrition facts and dietary practices use:
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9. Key Terms related to the Scientific Method
Hypothesis
Possible explanation about an observation that guides scientific research
Anecdote
Reports of personal experiences
Variable
Personal characteristic or other factor that changes and can influence an outcome
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10. Laboratory Experiments
An experiment is a systematic way of testing a hypothesis.
Experiments are often tested on cells or small animals.
Experiments may be conducted humans.
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11. Experimentation Most experiments have two groups: What is a placebo?
Treatment group: receives treatment
Control group: does not receive treatment; human subjects may receive a placebo
What is a placebo?
A fake treatment, such as a sham pill, injection, or medical procedure
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12. Experiments In vitro: In vivo:
“Test tube” experimenting on parts derived from living organism, such as cells
In vivo:
Testing on whole living organisms, such as lab rodents
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13. Human Research: Epidemiological Studies
Epidemiology is the study of occurrence, distribution, and causes of health problems in populations.
Two types of epidemiological studies:
Experimental (intervention)
Observational
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14. Experimental (Intervention) Epidemiological Studies
Experimental epidemiological studies can obtain information about health conditions that may have resulted from specific dietary practices.
Human subjects divided into two groups:
Experimental (receive treatment)
Control (no treatment—typically receive placebo)
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15. What Is the Placebo Effect?
The placebo effect occurs when a person reports a positive (or negative) reaction to a treatment even though he or she received the placebo.
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16. Observational Epidemiological Studies
Most human epidemiological research is observational.
Case-control study: individuals who have a health condition are compared with individuals with similar characteristics who do not have the condition.
Cohort study: study that measures variables in a group of people over time
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17. Epidemiological studies may be:
Prospective
Means “to look forward”
Follows group of healthy people into the future and looks for factors that may have contributed to changes in their health
Retrospective
Means “to look back”
Examines people’s past exposures to explain why some people are affected by a condition and not others
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18. Epidemiological Studies
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19. Limitations of Epidemiological Studies
Cannot establish causation, that is, whether a practice is responsible for an effect.
When two events or observations occur simultaneously within a population, it is not necessarily an indication that one is related to each other.
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20. Correlations What is a correlation? A relationship between variables
Occurs when two variables change over the same period
Important to understand that some changes could be coincidences and not the result of “cause and effect” relationships
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21. Examples of Direct and Inverse Correlations
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22. Elements of an Experimental Epidemiological Study
Reviewing scientific literature
Developing a hypothesis
Designing the study
Double-blind studies
Reviewing human subjects research designs
Conducting human research
Analyzing data, drawing conclusions, and reporting findings
Research bias
Spreading the news
Following up with more research
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23. Confusion and Conflict
The science of nutrition is constantly evolving.
Old beliefs are discarded and advice changes as nutrition scientists conduct more research and gain greater understanding.
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24. Nutrition Information: Fact or Fiction
Be wary of ads for nutrition-related products that rely on testimonials and anecdotes.
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25. Be Skeptical of Claims
Do not assume that information in popular media is reliable.
First Amendment to U.S. Constitution guarantees freedom of speech.
Consumers are responsible for questioning and researching accuracy of nutrition information.
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26. Ask Questions
What motivates the authors, promoters, or sponsors to provide the information?
Is the source scientific, such as an article in a peer-reviewed nutrition journal?
If a study is cited, how was the research conducted?
Does source cite respected nutrition or medical journals or mention reliable experts?
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27. What Is Quackery? Quackery is promoting useless medical treatments.
Practicing medicine without proper training is illegal.
BUT, providing nutrition information and advice without proper training is legal.
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28. Look for Red Flags (Signs of Unreliable Nutrition Information)
Promises of quick and easy remedies
Claims that sound too good to be true
Scare tactics
Personal attacks on registered dietitians or conventional scientists
Statements about the superiority of natural dietary supplements
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29. Look for Red Flags (cont.)
Testimonials and anecdotes
Information that promotes a product’s benefits while overlooking its risks
Vague, meaningless, or scientific-sounding terms
Sensational statements without citing references or sources
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30. Look for Red Flags (cont.)
Recommendations based on a single study
Information concerning nutrients or human physiology that are not supported by reliable scientific evidence
Dramatic generalizations
Disclaimers, usually in small or difficult-to-read print
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31. Using the Internet Wisely
Be careful and consider sources of Internet information
Consider:
Who or what organization sponsors site?
Is information intended to promote a product’s sales?
Is there a comprehensive disclaimer such as “not responsible or obligated to verify statements?”
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32. Tips for Searching Nutrition Information on the Internet
6. Do not trust a site that attacks medical or scientific establishment.
7. Avoid sites that provide online diagnoses or treatments.
8. Be wary of commercial sites (*.com) even those with links to reliable sites.
9. Avoid providing your personal information.
Use multiple web sites, especially government sites.
Be wary of survey sites.
Rely on sites reviewed or managed by health professionals.
Look for Health on the Net symbol.
Do not trust a site that does not indicate valid sources.
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33. Reliable Nutrition Experts
Where do you find factual answers about food or nutrition?
There is no standard legal definition for “nutritionist” or “nutritionalist.”
Physicians generally do not have extensive education in nutrition.
Reliable sources of information: college or university nutrition instructors or registered dietitians.
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