Nutrition Chapter 2

scientific method

-make observations that generate questions -formulate hypotheses to explain events -review current scientific literature (published studies) that relate to the questions -design studies, perform tests, and collect data -analyze data and draw conclusions based on the results -share results with peers (report findings) -conduct more research, the results of which may confirm or refute previous findings

consumers

-need to recognize that conflicting findings often result from differences in the ways various studies are designed

double-blind studies

-neither the investigators nor the subjects are aware of the subjects' group assignments -codes are used to identify a subject's group membership, and this information is not revealed until the end of the study -maintaining such secrecy is important during the course of a human study involving placebos, because researchers and subjects may try to predict group assignments based on their expectations

variable

-personal characteristic or other factor that can change and influence an outcome -can influence the outcome of an experimental study -only one is changed during an experiment

multivitamin.mineral

-products that may contain several vitamins and minerals

control group

-the group in an experiment that are left alone to act as a basis of comparison -allows scientists to compare results between the two study groups to determine whether the treatment had any effect

tradition

conventional wisdom

food service system management dietitians

direct food systems in hospitals, schools, or other settings

registered dietitians

discard conventional beliefs, explanations, and practices when the results of current scientific research no longer support them

Joseph Goldberger

discovered deficiency diseases, starting with ellagra which he deemed due to poor diets as opposed to an infectious disease

evidence based

factual information supported by scientific evidence

peers

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

placebo effect

response to taking a placebo, believed to be due to wishful thinking that their health will improve from their medical treatment

dietetics

the application of nutrition and food information to treat many health-related conditions

inverse/negative correlation

when one variable increases and the other one decreases

direct/positive correlation

when two variables are changing in the same direction

peer review

-a critical analysis conducted by a group of "peers" -occurs before articles are accepted for publication -if peers agree that a study was well conducted, its results are fairly represented, and the research is of interest to the journal's readers, these scientists are likely to recommend that the journal's editors publish the articles

testimonial

-a personal endorsement of a product -people are usually paid to provide these for advertisements, and should thus be considered biased

experiment

-a systematic way of testing a hypothesis -often conducted on small mammals before performing similar research on humans

outcomes

-nutrition scientists often conduct experimental studies to obtain information about such health conditions that may result from specific dietary practices

treatment group

the group in an experiment that are given the treatment

placebo

-a fake treatment, such as a sham pill, injection, or medical procedure that mimics the treatment -smells like, tastes like, and looks like the supplement pill with an active ingredient that is given subjects in the treatment group -has inert ingredients, which do not produce any measurable physical changes

quakery

-promotion of useless medical treatments

epidemiology

-the study of the occurrence, distribution, and causes of health problems in populations -use physical examinations of people to obtain health data, such as weight and height -collect other kinds of information by conducting studies

in vitro

-"test tube" experiments that are performed on cells or other components derived from living organisms -must be cautious when drawing conclusions from such experiments, because components removed from a living thing may not function the same way they do when they are in the entire life form

registered dietitian (RD), registered dietitian nutritionist (RDN), or licensed dietitian nutritionist (LDN)

-a college-trained health care professional who has extensive knowledge of foods, nutrition, and dietetics -has completed a baccalaureate degree program approved by the Accreditation Council for Education in Nutrition and Dietetics of the Academy of Nutrition and Dietetics

correlation

-a relationship between variables -occurs when two variables change over the same period -can be established by epidemiological studies

in vivo experiment

-an experiment that uses a whole living organisms, such as mice -scientists must be careful when applying the results of in vivo animal studies to people, because of the physiological differences between humans and other animals

clinical dietitians

-can work as members of medical teams in hospitals or clinics -can also work as community nutritionists in public health settings -can work as dietary counselors in private practice or with wellness programs

nutrition

-constantly evolving -old beliefs and practices are discarded when they are not supported by more recent scientific evidence, and new principles and practices emerge from the new findings

cohort study

-epidemiologists collect and analyze various kinds of information about a large group of people over time -the scientists are generally interested in making associations between exposure to a specific factor and the subsequent development of health conditions -can be retrospective or prospective

random assignment

-helps ensure that the members of the treatment and control groups have similar variables, such as age and other characteristics

case-control study

-individuals with a health condition such as heart disease or breast cancer are matched to persons with similar characteristics who do not have the condition -information such as personal and family medical histories, eating habits, and other lifestyle behaviors are collected from each participant in the study -by analyzing the results, researchers identify factors that may have been responsible for the illness -scientists may be able to identify dietary practices that differ between the two groups

red flags

-promises of quick and easy remedies for complex health-related problems -claims that sound too good to be true -scare tactics that include sensational, frightening, false, or misleading statements about a food, dietary practice, or health condition -personal attacks on the motives and ethical standards of registered dietitians or conventional scientists -statements about the superiority of certain dietary supplements or unconventional medical practices -testimonials and anecdotes as evidence of effectiveness -information that promotes a product's benefits while overlooking its risks -vague, meaningless, or scientific-sounding terms to impress or confuse consumers -sensational statements with incomplete references of sources -recommendations based on a single study -information concerning nutrients or human physiology that is not supported by reliable scientific evidence -results disclaimers, usually in small or difficult-to-read print

hypothesis

-question -a possible explanation for an observation that guides scientific research

anecdotes

-reports of personal experiences -how nutrition facts and dietary practices used to be based on

studies/ scientific investigations

-researchers design these to answer their questions -follow generally accepted methods -used to collect nutrition information and establish nutrition facts

pseudoscience

-the presentation of information masquerading as factual and obtained by scientific methods -presented in a way that is designed to convince people without science backgrounds that the nutrition-related information is true

retrospective cohort study

-to look back -researchers collect information about a group's past exposures and identify current health outcomes

prospective cohort study

-to look forward -a group of healthy people are followed over a time period and any diseases that eventually develop are recorded -scientists try to identify links between exposures and diseases that occurred between the beginning and end of the study period

complementary and alternative medicine

-variety of health care practices that are not accepted by the majority of conventional medical practitioners

questions to ask:

-what motivates the authors, promoters, or sponsors to provide the information? do you think they are more interested in your health and well-being or in selling their products? -is the source scientific, such as an article from a peer-reviewed nutritional journal? -if a study is cited, how was the research conducted? did the study involve humans or animals? if people participated in the study, how many subjects were involved in the research? who sponsored the study? -to provide scientific support for claims, does the source cite respected nutrition or medical journals or mention reliable experts?

causation

-whether a practice is responsible for an effect -epidemiological studies do not establish this