Unit 1 DB: Comparing Different Diets

The Scientific Method

• In the past, nutrition facts and dietary practices were often based on tradition or anecdotes (personal experiences).

• Today’s researchers design studies that follow the scientific method, a systematic approach to answering questions: – Stating the problem – Collecting background information – Forming a hypothesis – Testing the hypothesis (experimentation) – Making observations and recording data – Analyzing data and drawing conclusions

Common Methods Used by Scientists

There are several common methods scientists use to collect nutrition information and establish nutrition facts:

• Laboratory Experiments – A controlled experiment has independent, dependent, and controlled

variables • in vivo versus in vitro studies

Common Methods (continued)

• Human Research – Experimental (Intervention) Studies: subjects in the control group given a

sugar pill placebo • Double-Blind Studies: neither investigators nor subjects are aware of the

subjects’ group assignments – Epidemiological Studies: findings related to the occurrence, distribution, and

causes of health problems in populations (though generally not useful for finding cause-and-effect relationships)

Common Methods (continued)

• Peer Review – Before articles are accepted for publication, they undergo critical analysis by

investigators who are not part of the study but experts involved in related research

• Do peers agree study was well-conducted? • For example, peer-reviewed articles appear in Journal of the American

Medical Association (JAMA)

Becoming a Critical Consumer of Nutrition Information

• Ask questions – What motivates the author, promoter, sponsor to provide the

information? – Is the source scientific? (such as an article from a peer-reviewed

nutrition journal) – Are studies cited? How was the research conducted? – To provide scientific support for their claims, does the source refer to

articles in respected journals or mention reliable experts? (such as someone earning a Ph.D. in human nutrition from an accredited university)

• Look for red flags – Clues that indicate a source of information is unreliable

• Use the Internet wisely – Avoid sources of information that may be biased – Does the site promote or sell products for profit (*.com)?

Red Flags

• Review specific examples of these “Red Flags” in your textbook reading:

1. Promises of quick and easy remedies for complex health problems 2. Claims that sound too good to be true 3. Scare tactics that include sensational, frightening, false, or misleading statements 4. Personal attacks on the motives and ethical standards of RDNs or scientists 5. Statements about the superiority of certain dietary supplements or unconventional medical practices 6. Testimonials and anecdotes as evidence of effectiveness 7. Information that promotes a product’s benefits while overlooking its risks 8. Vague, meaningless, or scientific-sounding terms to impress or confuse consumer 9. Sensational statements with incomplete references of sources 10. Recommendations based on a single study 11. Information concerning nutrients or human physiology that is not supported by reliable scientific evidence 12. “Results” disclaimers, usually in small or difficult-to-read print

Reliable Nutrition Experts

• A registered dietitian (RD) or registered dietitian nutritionist (RDN) is a college-trained health care professional with extensive knowledge of foods, nutrition, and dietetics (the application of nutrition and food information to help treat many health-related conditions) – The titles RD and RDN are legally protected (these people must be certified

by the appropriate accrediting agency) – An RDN has completed a baccalaureate degree program approved by the

Accreditation Council for Education in Nutrition and Dietetics (ACEND) of the Academy of Nutrition and Dietetics (largest organization of dietitians in U.S.)