Evaluating Nutrition Information Chapter 2 Evaluating Nutrition Information Nutrition-Chapter 2 Nutrition Chapter 1

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 Nutrition-Chapter 2

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!*** Nutrition-Chapter 2

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. Nutrition-Chapter 2

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! Nutrition-Chapter 2

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 Nutrition-Chapter 2

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. Nutrition-Chapter 2

Today nutrition facts and dietary practices use: Nutrition-Chapter 2

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 Nutrition-Chapter 2

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. Nutrition-Chapter 2

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 Nutrition-Chapter 2

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 Nutrition-Chapter 2

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 Nutrition-Chapter 2

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) Nutrition-Chapter 2

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. Nutrition-Chapter 2

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 Nutrition-Chapter 2

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 Nutrition-Chapter 2

Epidemiological Studies Nutrition-Chapter 2

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. Nutrition-Chapter 2

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 Nutrition-Chapter 2

Examples of Direct and Inverse Correlations Nutrition-Chapter 2

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 Nutrition-Chapter 2

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. Nutrition-Chapter 2 23

Nutrition Information: Fact or Fiction Be wary of ads for nutrition-related products that rely on testimonials and anecdotes. Nutrition-Chapter 2

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. Nutrition-Chapter 2

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? Nutrition-Chapter 2

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. Nutrition-Chapter 2

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 Nutrition-Chapter 2 28

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 Nutrition-Chapter 2 29

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 Nutrition-Chapter 2 30

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?” Nutrition-Chapter 2

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. Nutrition-Chapter 2 32

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. Nutrition-Chapter 2