Nutrition Chapter 2
Example of positive correlation
when women gain less weight than average during pregnancy, the birth weights of their babies tend to be lower than average
Which statement is false a. melatonin may help with sleep disorders b. niacin cures pellagra c. white sugar causes stomach ulcers d. all are correct
c. white sugar causes stomach ulcers
Registered dietician
A registered dietitian is a college-trained health care professional who has extensive knowledge of foods, nutrition, and dietetics, the application of nutrition and food information to treat many health-related conditions. The title "registered dietitian" is legally protected.
what are dietary supplements?
According to results of surveys, about 20% to 50% of adult Americans used these and other dietary supplements during the period 1999-2002
The government agency that enforces consumer protection laws by investigating false or misleading health-related claims is the Federal Trade Commission (FTC). Environmental Protection Agency (EPA). Agricultural Research Service (ARS). Centers for Disease Control and Prevention (CDC).
FTC
Goldberger's hypothesis
Goldberger's hypothesis is a possible explanation for an observation that guides scientific research. He hypothesized that the missing dietary factor was in meat, milk and other foods eaten regularly eaten by people with higher incomes.
How are dietary supplements regulated?
The US food and drug administration (FDA) is the federal agency responsible for ensuring the safety and effectiveness of medications and other health related products. The FDA strictly regulates the development, production and marketing of new medications. A drug is a substance, natural or human made that alters body function. Drugs can be beneficial as well as harmful. Manufacturer must submit evidence indicating the product has been extensively tested, is safe and effective. If FDA experts have questions about side effects or usefulness they can reject the petition to sell.
Mice and Rats
Certain rats and mice are raised for experimentation purposes These rodents are inexpensive to house in labs and their food and living conditions can be carefully controlled. An experiment that uses whole living organisms such as mice is called an in vivo experiment. Nutrition researchers also perform controlled la experiments on cells or other components derived from living organisms. These studies are in vitro or "test tube" experiments
clinical dietician definition
Clinical dietitians can work as members of medical teams in hospitals or clinics. Clinical dietitians can also work as community nutritionists in public health settings or as dietary counselors in private practice or with wellness programs. Food service systems management dietitians direct food systems in hospitals, schools, or other settings. Although most registered dietitians work in health care settings, some are educators or researchers.
Who is responsible for ensuring the safety of medications and other health-related products?
FDA
By conducting studies, epidemiologists learn much about the influence of diet on health
If one group is more likely to develop a health disorder than another group and the 2 populations consume very different diets scientists can speculate about the role diet plays in this difference. Ex. Breast cancer is generally higher among women in western countries than women in asian countries and western women have lower intakes of soy products than asian women. Based on this you might conclude eating a soy rich diet preents breast cancer but is your conclusion valid? An experiment would have to be conducted.
After the results of a study are published in a nutrition-related journal or reported to health professionals attending a meeting of a nutrition or medical society, the media (e.g., newspapers, magazines, Internet news sources) may receive notice of the findings.
If the information is simplistic and sensational, such as a finding that drinking green tea can result in weight loss, it is more likely to be reported in the popular press. In many instances, you learn about the study's results when they are reported in a television or radio news broadcast as a 15- or 30-second "sound bite." Such sources generally provide very little information concerning the way the study was conducted or how the data were collected and analyzed.
Gingko bilova
Improves memory, reduces risk of alzheimers and other forms of dementia. Lack of scientific evidence to support claims, may increase the risk of bleeding and cause allergic reactions, headaches, intestinal upsets and nausea. Gingko seeds are toxic.
In the mid 1950s the medical community accepted the cause of peptic ulcers as stress and poor diet. Monkeys and rodents living under stressful conditions and humans recovering from severe burns often developed ulcers.
In 1982, Australian physicians Barry Marshall and Robin Warren isolated a type of bacteria from the stomachs of patients with gastritis, inflammation of the stomach lining that can result in ulcers. They hypothesized that this microbe might be related to the development of gastritis and peptic ulcers. They suggested treating the condition with antibiotics. Other physicians were skeptical.
When a population's intake of sugar sweetened soft drinks increase, the percentage of over weight people in the population increases.
In this case the correlation is direct or positive because the 2 variables - body weight and regular soft drink consumption are changing in the same direction, they are both increasing
Case Control Study
Individuals with a health condition (cases) such as heart disease or breast cancer are matched to persons with similar characteristics who do not have the condition (controls). Info such as personal and medical histories, eating habits and other lifestyle behaviors are collected. By analyzing the results of case control studies, researchers identify factors that may have been responsible for the illness
Consumers also need to be alert for promoters' use of pseudoscience,
the presentation of information masquerading as factual and obtained by scientific methods. In many instances, pseudoscientific nutrition or physiology information is presented with complex scientific-sounding terms, such as "enzymatic therapy" or "colloidal extract." Such terms are designed to convince people without science backgrounds that the nutrition-related information is true. Often, promoters of nutrition misinformation try to confuse people by weaving false information with facts into their claims, making the untrue material seem credible too.
Confusion and conflict
The science of nutrition is 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. By now you should understand that science involves asking questions, developing and testing hypotheses, gathering and analyzing data, drawing conclusions from data, and sometimes, accepting change.
Nutrition researchers rely on scientific method that involves making observations, asking questions, developing hypothesis, performing tests, and collecting and analyzing data to find relationships between variables.
a variable is A factor such as a person's age, weight, or environment that can change and influence an outcome. After analyzing data, researchers develop conclusions from the data and report on the findings. Other scientists can test the findings to support or refute them.
A group of scientists conduct a scientific study to investigate dietary factors that influence the development of obesity. Which of the following activities is not likely to be a component of their research? a. Submitting an article describing the study to a peer review journal b. Posting findings at the main researcher's internet website c. Collecting data and analyzing results d. Making observations and formulating a hypothesis
b. Posting findings at the main researcher's internet website
Researchers at a major american university plan a study to investigate lifestyle factors that contribute to heart disease. Which of the following activities is likely to be a component of their research? a. obtaining FDA and FTC approval b. Submitting an article describing the study to a peer reviewed journal c. Posting significant findings at the main researcher's website d. None of these is correct
b. Submitting an article describing the study to a peer reviewed journal
Generally, epidemiological studies establish causation. prove correlations. cannot determine cause-and-effect relationships. are experimental-based research efforts that examine two variables.
cannot determine cause-and-effect relationships.
Comparing individuals with iron-deficiency anemia to individuals who have very similar characteristics but are healthy would be an example of a prospective study. an anecdotal study. a retrospective study. a case-control study.
case control study
a researcher wants to identify factors that increase the risk of stomach cancer in men. His study design involves enrolling 250 men who have stomach cancer and 250 without. What kind of study is this?
case-control
Cure for pellagra is
niacin
A radio host claim raises a red flag.
"All ingredients in this product have been scientifically tested and clinically proven"
Dietary supplements
20 to 50% of adult Americans used supplements from 1999 - 2002 According to the Dietary Supplement and Health Education Act of 1994, (DSHEA), a dietary supplement is a product other than tobacco that adds to a person's dietary intake and contains one or more dietary ingredient including nutrients or botanicals, is taken by mouth, is not promoted as a conventional food or the only item of a meal or diet
A direct positive correlation
A direct positive correlation As a population's intake of sugar-sweetened soft increases the percentage of overweight people in that population increases
Experiment
A systemic way of testing a hypothesis. Because of safety and ethical concerns, nutrition scientists often conduct experiments on small mammals before performing similar research on humans
In vivo
An experiment that uses whole living organisms, such as mice, is called an in vivo experiment.
Case control study, cohort study, correlation defintions
Case control study Study in which 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 of a group of people over time Correlation Relationship between 2 variables
Control group
Control group Group being studied that does not receive the treatment
supplements include
Dietary supplements include nutrient pills, protein powders, and herbal extracts, as well as energy bars and drinks. Many dietary supplements are often referred to as "nutraceuticals," but there is no legal definition for this term.
Goldberger died in 1929, eight years before Dr. Conrad Elvehjem and his team of scientists at the University of Wisconsin isolated a form of the vitamin niacin from liver extracts.
Elvehjem discovered niacin cured "black tongue" a condition affecting dogs that was similar to pellagra. Niacin was determined to be effective in treating pellagra and the medical professionals finally accepted the fact that pellagra was caused by dietary deficiency.
Epidemiology
Epidemiology Study of the occurrence, distribution, and causes of health problems in populations
Double blind study
Experimental design in which neither the participants nor the researchers are aware of each participants group assignment
Peer review
Expert critical analysis of a research article before it is published
Govt. agency that enforces consumer protection laws
Federal Trade Commission
Who investigates claims about false or misleading claims?
Federal Trade Commission
Epidemiological studies
For decades medical researchers noted differences in rates of chronic diseases and cause of death among various populations
Goldberger tested his hypothesis in two Mississippi orphanages
Goldberger gave these foods to the children in the orphanages and patients in a Georgia mental institution who were suffering from pellagra and they were cured of the disease.
Coenzyme Q-10
Increases exercise tolerance, prevents heart disease and cancer, reverse signs of aging and disease. Antioxidant made by the body and involved in energy metabolism insufficient scientific evidence to support these claims. May reduce elevated blood pressure but more research is needed. Low toxicity but long term safety is unknown.
Inverse correlation (negative)
Inverse correlation (negative) As a population's fruit intake increases, the percentage of people in that population with hypertension declines
Observational Epidemiological Studies
Involves case control study or cohort study designs
Epidemiology
Is the study of the occurrence, distribution, and causes of health problems in a population.
Red yeast rice
Lowers blood cholesterol, reduces risk of heart disease, may be effective for people who cannot take prescription medications to reduce lower blood cholesterol. Long term safety unknown.
Goldberger observed not everyone exposed developed pellagra
Many prisoners had pellagra but not the guards or administrators - Goldberger rejected the medical establishments notion that pellagra was an infectious disease
Diabetes
Most common type of diabetes occurs most frequently among Native American, Hispanic and non-Hispanic African American adults than among non-Hispanic, white American adults. Breast cancer is more common among non-Hispanic white females who are members of other American racial or ethnic groups.
Developing a hypothesis
Multiple factors, including a person's genetic susceptibility (inherited proneness) to develop the disease, usually influence whether the chronic disease occurs. For example, many environmental, physiological, and lifestyle variables are responsible for the development of breast cancer in women. By conducting a review of scientific articles, the researchers learn that body weight, alcohol consumption, and age are some of the variables that influence a woman's risk of breast cancer.10 Therefore, it is possible that variables besides soy intake account for the different rates of breast cancer observed between Western and Asian women. With this information in mind, the scientists are ready to develop their hypothesis.
Medical researchers must be careful when applying the results of in vivo animal studies to people because the physiological differences between humans and other animals.
Nevertheless, scientists are often able to determine the safety and effectiveness of treatments by conducting research on lab animals before engaging in similar studies in humans. Researchers are cautions when drawing conclusions from results of in vitro experiments because components removed from a living thing may not function the same way when in their entire form
a team of scientists extract chemicals from the leaves of a common houseplant, can they call this a supplement?
No
in vitro
Nutrition researchers also perform controlled laboratory experiments on cells or other components derived from living organisms. These studies are in vitro or "test tube" experiments.
Despite Goldberger's findings connecting nutrition with pellagra
Other members of the medical establishment rejected his findings and continued to think pellagra was an infectious disease
Peer review journals
Peer-reviewed journals usually require authors of articles to disclose their affiliations and sources of financial support. Such disclosures may appear on the first page or at the end of the article. By having this information, readers can decide on the reliability of the findings. Although peer review helps ensure that the scientists are as ethical and objective as possible, it is impossible to eliminate all research bias.
In the 1900s Pellagra was widespread in the US especially in the south
Pellagra: weak, diahrrea, skin rash, mental confusion. Thousands every year died from this disease
Placebo
Placebo Fake treatment such as a sham pill, injection or medical procedure
Hypothesis
Possible explanation about an observation that guides scientific research
Pseudoscience
Presentation of information masquerading as factual and obtained by scientific methods
Look for 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 Dramatic generalizations Results disclaimers, usually in small or difficult-to-read print
Valerian
Promotes relaxation, treats sleep disorders, evidence to support is inconsistent, dizziness, headaches, stomach upset, questions on long term safety
An authors needs what credentials after their name?
R.D.
In a retrospective cohort study
Researchers collect information about a group's past exposures and identify current health outcomes. For ex. Nutritional epidemiologists might examine whether a group of people who have stomach cancer consumed more charcoal broiled meat (the exposure) in the past than a group of people with similar characteristics who did not have stomach cancer
Becoming a registered dietician
Three major professional divisions: clinical dieticians, community nutrition and food service management systems Clinical: can work as community nutritionists in public health settings or as dietary counselors in private practice with wellness programs Food service systems management dieticians can work in hospitals, schools, etc. An RD has a baccalaureate degree program
Retrospective means
To look back
Prospective means
To look forward in time
Conducting Human Research
To reduce the likelihood that the results of the soy study occur by chance, the researchers enroll in the study a large group of premenopausal women (800, for example) who are healthy but have higher-than-average risks of breast cancer. Subjects are randomly assigned into two groups; 400 are in the treatment group and 400 are in the control group. The investigative team provides a supply of wafers to the treatment group's participants and instructions concerning their daily consumption. By following these instructions, each treatment group member will consume 25 grams of soy/day. Members of the control group are also given a supply of wafers, but their wafers are the placebos that do not contain soy. Both groups are given the same instructions concerning their food intake, dietary record keeping, health care reporting, and lifestyle for the duration of the study.
treatment group
Treatment group Group being studied that receives a treatment
Evening primrose oil
Treats eczema, relieves arthritis and post menopausal symptoms. May relieve eczema, little scientific evidence to support other claims. No risks identified.
Ginger
Treats morning sickness and other forms of nausea, relieves stomach upsets, can safely treat morning sickness and may reduce other forms of nausea, lack of scientific evidence to support other health claims, no risks identified
Ask Questions
What motivates the authors, promoters, or sponsors to provide the information? Is the source scientific, such as an article from a peer-reviewed nutrition 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?
A testimonial is an unbiased report about a product's value. a scientifically valid claim. a personal endorsement of a product. a form of scientific evidence.
a personal endorsement of a product.
A physician tells a patient that his mild depression are not the result of serious health problem and suggests trying exercise and St. John's wort. this is an example of
an indication the physician practices integrated medicine
Derek tells his friends about a supplement that makes him 200% stronger. This is an
anecdote
Which statement is true? a. medicinal herbs must undergo testing for safety b. the EPA regulates labeling of supplements c. Dietary supplements can be recalled when the products are improperly labeled d. manufacturers of supplements must inform the FTC about negative health reports that result from the use of their products
c. Dietary supplements can be recalled when the products are improperly labeled
Having a control group enables researchers to
compare findings of the control group with those of the experimental group
Designing the study
conducting human experiments can be costly and often involves ethical concerns. people are not likely to enroll in clinical studies that may require living in tightly controlled settings such as the nutrition research unit of a major university's medical school for a few days or weeks. researchers often design studies to allow subjects to maintain their lifestyle practices, except for the variable being studied.
A group of registered dieticians is planning to conduct a scientific study to investigate the effects of eating honey on school age children's behavior. At first reasearchers will: a. identify relationships between variables b. analyze the hypothesis c. gather data d. make observations
d. make observations
be skeptical
do not assume that all nutrition information presented in the popular media is reliable. The First Amendment to the U.S. Constitution guarantees freedom of the press and freedom of speech, so people can provide nutrition information that is not true. Thus, the First Amendment does not protect consumers with freedom from nutrition misinformation or false nutrition claims. The U.S. Food and Drug Administration (FDA) can regulate nutrition- and health-related claims on product labels, but the agency cannot prevent the spread of health and nutrition misinformation published in books or pamphlets or presented in television or radio programs. As a consumer, you are responsible for questioning and researching the accuracy of nutrition information as well as the credentials of the people making nutrition-related claims.
Which of the following is a popular dietary supplement? a. dried mango b. aspirin c. poppyseed extract d. echinacea
echinacea
An aspect of ______ involves studying causes of health problems in a population. epidemiology technobiology diseasiology censusology
epidemiology
Which of the following substances would be classified as a dietary supplement according to the Dietary Supplement and Health Education Act of 1994? tobacco aspirin ginseng All of the choices are correct.
ginseng
The first step of the scientific method usually involves gathering data. developing a hypothesis. identifying relationships between variables. making observations.
making observations
Dietary supplements include
pills, protein powders, herbal extracts, energy bars and drinks. They are referred to as nutraceuticals but there is no definition for this term
A fake treatment is a(n) anecdote. double-blind study. pseudoscience experiment. placebo.
placebo
Researchers are conducting a study to determine the effects of vitamin C on the human immune system. The study involves providing pills that contain vitamin C to one group of human subjects that do not contain vitamin C. The pills that do contain vitamin C are
placebos
quackery
promotion of useless medical practices
A group of researchers wants to determine whether certain dietary factors are associated with the risk of attention deficit disorder. They follow a group of 500 healthy newborns for 10 years. At the end of the study they analyze the data. This is a
prospective study
When an experiment or study is completed and the results analyzed,
researchers summarize the findings and seek to publish articles with information about their investigation in scientific journals. Before articles are accepted for publication, they undergo peer review, a critical analysis conducted by a group of "peers." Peers are investigators who were not part of the study but are experts involved in related research. 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 article. Examples of peer-reviewed medical and nutrition journals include the Journal of Nutrition, American Journal of Clinical Nutrition, The New England Journal of Medicine, Journal of the American Medical Association, and Nutrition Reviews.
Actress endorses a product, this is
testimonial
A speaker at a health fair claims because he has a PHD he is an expert as a registered dietician
the speaker is mis-using the RD title
The filth party
Goldberger's critics were still not satisfied. He experimented on himself and volunteers during what he termed a filth party. They applied secretions taken from the inside of the nose and throat of a patient with pellagra into their noses and throats. They swallowed pills made with flakes of skin scraped from the rashes of the people with the disease. They gave eachother injections of blood from the infected patients. None of them contracted the disease. Despite the evidence, some still resisted the idea that pellagra was associated with diet.
Goldberger enrolled a group of healthy Mississippi inmates in an experiment to satisfy his colleagues
In 1916 Goldberger ended the controversy. He fed the prisoners corn and molasses based diets commonly eaten in the southern states. After a few months more than half the inmates developed pellagra.
Acidophilus
Live bacterial culture reduces risk of harmful bacterial overgrowth in large intestine May improve health by restoring the balance of beneficial to harmful bacteria in the intestinal tract Infectious complications can occur when probiotics are used by person with inflammation of the pancreas (pancriatitits)
Garlic
Lowers blood cholesterol levels, does not lower cholesterol consistently, may reduce elevated blood pressure. Can cause allergic reaction, unpleasant body odor, and interfere with prescription blood thinners
Fish oil
Prevents heart disease and stroke. Cures rheumatoid arthritis, reduces depression and risk of alzheimers. Source of omega 3 fatty acids reduces inflammation and lowers elevated blood triglyceride (fat) levels but more research is needed to determine other health benefits. May interfere with blood clotting, increasing risk of hemorrhagic stroke, cod liver oil contains vitamin A which is toxic when taken in large doses.
Testimonial
Testimonial Personal endorsement of a product
Is this true or false?
according to scientific research most dietary supplements provide considerable health benefits. This statement is false
According to the Dietary Supplement and Health Education Act of 1994 (DSHEA), a dietary supplement is a product (other than tobacco) that
adds to a person's dietary intake and contains one or more dietary ingredients, including nutrients or botanicals (herbs or other plant material) is taken by mouth is not promoted as a conventional food or the only item of a meal or diet
Which statement is true? a. Registered dieticians are not required to update their knowledge regularly b In the US only registered dieticians can provide health information legally c. The first amendment of the US constution protects people who spread misinformation d. Pseudoscience is the scientific study of the cause and treatment of disease
c. The first amendment of the US constution protects people who spread misinformation
Which of the following is an example of a peer-reviewed medical or nutrition journal? American Journal of Clinical Nutrition Ladies' Home Journal Men's Health Food & Nutrition Magazine
American Journal of Clinical Nutrition
Ginseng
Boosts overall health, treats erectile dysfunction, may lower blood glucose levels and benefit immune system but lack of scientific evidence to support other claims - may cause headaches, sleep disturbances, allergic responses, and gastrointestinal disturbances. Long term use may increase risk of toxicity
Why is a control group necessary?
It enables scientists to compare results between the 2 study groups to determine whether the treatment had any effect
Analyzing Data, Drawing Conclusions, and Reporting Findings
Nutrition researchers use a variety of statistical methods to analyze data collected from observations and experiments. These methods may enable the researchers to find relationships between the variables and health outcomes that were studied. As a result, scientists can determine whether their hypotheses are supported by the data.
Kava
Reduces stress, potential harm of using kava outweighs any benefits, toxic, can damage liver, may cause abdominal muscle movement, yellowed skin and sleepiness
Glucosomine
Relieves joint damage associated with arthritis. Some scientific evidence supports claims, more research needed. No risks identified
In 2010 a federal district court ruled in favor of the federal trade commission in a case involving companies that used unproven claims to promote Chinese diet tea and bio slim patch
The court fined the companies nearly 2 million for claiming that the products would enable to lose weight without diet or exercise
Pathways to become dieticians
There are two pathways students can take to become dietitians. A Coordinated Program (CP) combines classroom instruction with at least 1200 hours of supervised professional practice experience. A Didactic Program in Dietetics (DPD) provides classroom courses, and after graduation, students need to complete a dietetic internship program, which provides at least 1200 hours of supervised practice experience and generally takes six months to a year to complete. After completing a CP or dietetic internship program, students are eligible to take the national examination to become registered dietitians. To maintain their certification, registered dietitians must continually update their knowledge in the field of dietetics and obtain continuing education credits.
A group of scientists observe a group of college students over 4 years to determine which of their characteristics leads to weight gain. This study is an example of a case-control study. a prospective study. a retrospective study. an experimental study.
a prospective study.
Which of the following websites is most likely to provide biased and unreliable nutrition information? the site of a nationally recognized health association (*.org) a site that promotes or sells dietary supplements (*.com) the site of a U.S. government agency (*.gov)
a site that promotes or sells dietary supplements (*.com)
Cohort study
Epidemiologists collect and analyze various kinds of information about a large group of people over time. They are interested in making associations between exposure to a specific factor and the subsequent development of health conditions. Cohort studies can be retrospective or prospective.
Charcoal grilled meat experiment
Is it harmful? According to a hypothesis, chemical X in charcoal grilled meat is harmful. To test this hypothesis, 100 gentically similar 3 week old mice were split in 2 groups. One group (the treatment group) is fed a certain amount of chemical X daily for 52 weeks. The second group (the control group) does not receive the treatment during this period.
Green tea
Prevents or treats cancer, promotes weight loss, reduces blood cholesterol levels. Results of some studies indicate green tea protects against cancer or reduces cancer cell growth but results of human studies not conclusive. Green tea extracts may damage the liver, caffeine content may cause sleep disturbance, irritability, and digestive upset
Generally, epidemiological studies
cannot determine cause and effect relationships
The scientists examine the mice regularly for signs of health problems and record the results.
If the mice in the treatment group are as healthy as the mice in the control group at the end of the experiment the researchers may conclude that mice can safely consume the amount of chemical X used in the study on a daily basis for a year
Nutrition Information: Fact or Fiction
a testimonial, a personal endorsement of a product. People are usually paid to provide their testimonials for advertisements, therefore their remarks may be biased in favor of the product. Your friend's experience with taking the same weight-loss product is intriguing, but it is an anecdote and not proof that FatMegaMelter promotes weight loss. When your source of nutrition information is a testimonial, anecdote, or advertisement, you cannot be sure that the information is based on scientific facts and, therefore, reliable.
inverse correlation example
women who smoke 5 or more cigarettes a day during pregnancy are more likely to give birth to underweight babies than women who smoke fewer than 5 cigarettes a day during pregnancy
Reliable Nutrition Experts
you cannot always rely on someone who refers to him or herself as a "nutritionist" or "nutritionalist" for reliable nutrition information, because there are no standard legal definitions for these descriptors.
Lysine
Prevents recurrances of genital herpes, amino acid (component of protein), lack of evidence to support this claim, no risks identified
Steps to scientific method
1. Make observations that generate questions (review relevant literature) 2. Formulate hypotheses to explain events 3. Design studies, perform tests, collect data 4. Analyze data and draw conclusions based on the results 5. Share results with peers (report findings) 6. Conduct more research, the results may confirm or refute the previous findings
It is accepted today that something missing in diets can cause a nutrient deficiency disease
100 years ago however it was a novel idea and scientists believed only germs caused disease. It is interesting to note that raw corn contains niacin but in the form the body cannot digest. Consuming meat and milk helps prevent pellagra because these foods contain tryptophan, a component of proteins the body converts to niacin
1914 US Surgeon General assigned Joseph Goldberger to study Pellagra
1914 US Surgeon General assigned Joseph Goldberger to study Pellagra Most experts thought Pellagra was an infections disease because it was caught by people living in close quarters like prisons, mental health institutions
In a prospective cohort study
A group of healthy people are followed over a time period and any diseases that eventually develop are recorded. They try to identify links between exposure and diseases that occurred between the beginning and end of the study period
Reviewing scientific literature
Before nutrition scientists conduct studies, they perform a review of literature that involves a search of scientific articles previously published on their topic of interest. For example, a team of scientists plans to conduct a 5-year intervention study to determine the effects of adding 25 grams of soy/day to the diets of American women who are premenopausal (they can become pregnant) and have higher-than-average risks of breast cancer. The scientists prepare for their study by reading articles about research that examined the effects of soy intake on breast cancer risk. The findings and conclusions of the previous research may raise questions that can be explored in a new study.
Which of the following statements are true? In the US scientist can conduct studies on humans without telling them about the risks involved Before scientists begin the research they develop a hypothesis to guide their study A study that examines the effects of consuming different amounts of sugar on the health of rats is an in-vitro experiment All of these are correct
Before scientists begin the research they develop a hypothesis to guide their study
Echinacea
Boosts immune system, prevents the common cold and reduces cold symptoms. Mixed scientific evidence to support common cold prevention claims but research is ongoing. Generally safe but may provoke allergic response or intestinal upset
Experimental (intervention) Epidemiological studies
Conducted to obtain info about health conditions (outcomes) that may result from specific dietary practices. When using human subjects, researchers divide groups into treatment and control groups. They provide all participants with the same instruction and a form of intervention such as a dietary supplement or experimental food but only members of the treatment group receive the treatment. Control groups are given a placebo or sugar pills that are a fake treatment but mimics the treatment. It looks, smells and tastes the same as the supplement pill with an active ingredient that is given subjects in the treatment group. The placebo pill has inert ingredients. This allows scientists to compare the extent of the treatment's response with that of the placebo.
Which of the following statements is true?
Consumers can report negative health reports that may have resulted from their use of dietary supplements to the FDA
The ____ is the federal agency that tries to ensure the safety and effectiveness of health-related products. FDA FTC EPA USGS
FDA
Double-blind studies
Human experimental studies are usually double-blind—that is, 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. If the investigators who interview the participants are aware of their individual group assignments during the study, they may unwittingly convey clues to each subject, perhaps in the form of body language, that could influence the subject's belief about being in the experimental or control group. Subjects who suspect they are in the control group and taking a placebo may report no changes in their condition, because they expect a placebo should have no effect on them. On the other hand, subjects who think they are in the treatment group could insist that they feel better or have more stamina as a result of the treatment, even though the treatment may not have produced any measurable changes in their bodies. Ideally, subjects should not be able to figure out their group assignment while researchers are collecting information from them.
What appears to be a correlation between a behavior and an outcome could be a coincidence and not an indication of a cause and effect relationship between 2 variables
In a survey of lemonade consumption in Colorado over a 10 year period we might observe fewer people drank lemonade during the winter. In a survey of snow skiing accidents in Colorado during the same 10 year period, we might find that snow skiing accidents were more likely to occur during the winter. Does this mean lemonade consumption is inversely correlated to skiing accidents and people who do not drink lemonade have a greater risk of skiing accidents? This is far fetched.
Most commonly used dietary supplements
In the United States, the most commonly used dietary supplements are multivitamin/multimineral (MVMM) products that typically contain several vitamins and minerals.16 Among American adults, the most popular nonvitamin, nonmineral dietary supplements are fish oil or "omega 3," glucosamine, echinacea, and flaxseed oil and pills.17 Some people use dietary supplements, particularly those containing nutrients, because the products are recommended by their physicians or dietitians. Physicians, for example, may prescribe a prenatal MVMM supplement for their pregnant patients.
Scientists ask questions about the natural world and follow generally accepted, standardized methods to obtain answers to questions.
In the past, nutrition facts and dietary practices were based on intuition, common sense, conventional wisdom or antecdotes. Today, registered dieticians and other nutrition experts discard these beliefs when results of scientific research does not support them
Which of the following periodicals feature peer reviewed articles? a. Ladies home journal b. National Geographic c. Journal of Nutrition d. All
Journal of nutrition
In cases involving chronic diseases such as breast cancer, it is difficult to determine a single variable that is responsible for the development of the condition.
Multiple factors, including a person's genetic susceptibility (inherited proneness) to develop the disease, usually influence whether the chronic disease occurs. For example, many environmental, physiological, and lifestyle variables are responsible for the development of breast cancer in women. By conducting a review of scientific articles, the researchers learn that body weight, alcohol consumption, and age are some of the variables that influence a woman's risk of breast cancer.10 Therefore, it is possible that variables besides soy intake account for the different rates of breast cancer observed between Western and Asian women. With this information in mind, the scientists are ready to develop their hypothesis.
In the US, the most commonly used supplements are
Multivitamin/multimineral products that contain several vitamins and minerals. Most popular are fish oil, omega 3, glucosamine, echinachea, flaxeed oil and pills
Chondrotin
Relieves joint damage associated with arthritis, some scientific evidence supports health benefit claims, but more research is needed, often combined with glucosamine. No risks identified.
The Framingham Heart Study began in 1949 in MA
Over 5200 healthy participants (men and women) underwent extensive physical exams and questioning about their family and personal medical histories and lifestyle practices. Over the following years, a group of medical researchers periodically collected data concerning each persons health. If the person died, cause of death . Data was analyzed and found relationships between personal characteristics and health outcomes. Findings identified numerous risk factors for heart disease including smoking and hypertension. Researchers are still collecting data from the original participants as well as their descendants.
Check credentials
Practicing medicine without the proper training and licensing is illegal. However, providing nutrition information and advice without the proper training and licensing is legal. Quackery involves promoting useless medical treatments, such as copper bracelets to treat arthritis. To obtain information about a nutrition expert's credentials, enter the person's name at an Internet search engine and evaluate the results. For example, is the person associated with an accredited school of higher education or a government agency such as the U.S. Department of Agriculture? You can also visit www.quackwatch.org and submit an "Ask a Question" e-mail requesting information about a person's credentials from the site's sponsors.
St John's wort
Reduces depression, may be effective in treating mild to moderate depression, may interact with other herbal products and medications, including prescription antidepressants and oral contraception
Placebo effect
Response to a placebo
Becoming a Registered Dietitian
There are three major professional divisions for registered dietitians—clinical dietetics, community nutrition, and food service systems management.
Melatonin
Treats some sleep disorders, prevents jet lag, may be effective for treating certain sleep disorders and preventing jet lag, questions about long term safety
In 2010, a federal district court ruled in favor of the Federal Trade Commission (FTC) in a case involving companies that used unproven claims to promote "Chinese Diet Tea" and "Bio-Slim Patch."
The court fined the companies nearly $2 million for claiming that the products would enable people to lose weight without diet and exercise.
Goldberger found a connection with pellagra to diet and nutrition.
The diet consisted of hominy grits (a corn product), potatoes, cabbage, and rice. This low-protein diet was associated with poverty throughout the south. People who ate more meat, milk and fresh vegetables and had higher incomes did not develop pellagra.
Flaxseed and flaxseed oil
Acts as a laxative, reduces blood cholesterol levels. Nonanimal source of omega 3 fatty acids. Seeds have laxative effects. May benefit people with heart disease, more research needed, generally safe.
Epidemiologists often use physical examinations of people to obtain health data
Additionally they may collect info by collect information using surveys. Surveys question people about their personal and medical histories, invironmental exposures, health practices and attitudes. 2 types of epidemiological research are experimental (intervention) studies and observational studies. These can provide nutritional epidemiologists with clues about the causes, progression and prevention of diet related diseases.
Registered dietician credentials
An R.D. has completed a baccalaureate degree program approved by the Commission on Accreditation for Dietetics Education of the Academy of Nutrition and Dietetics, the largest organization of dietitians in the United States. As undergraduate students, dietetics majors are required to take a wide variety of college-level courses, including food and nutrition sciences, organic chemistry, biochemistry, biology, physiology, microbiology, food service systems management, business, and communications classes.
Anecdotes / Variable definitions
Anecdotes Reports of personal experiences Variable Personal characteristics or other factor that changes and can influence an outcome
Beta carotene
Antioxidant, reduces risk of cancer and heart disease, source of vitamin A, excess may stimulate cancer cell growth
Elements of an experimental epidemiological study
Scientific studies can have very complicated designs and involve several years and thousands of dollars to plan and conduct. Most nutrition related research involving humans incorporate some basic steps, reviewing scientific literature, developing a hypothesis, designing the study, conducting research, analyzing the results, reporting the results and possible conducting another study related to the original findings.
Research Bias
Scientists expect other researchers to avoid relying on their personal attitudes and biases ("points of view") when collecting and analyzing data, and to evaluate and report their results objectively and honestly. This process is important because much of the scientific research that is conducted in the United States is supported financially by the federal government, nonprofit foundations, and drug companies and other private industries. Some funding sources can have certain expectations or biases about research outcomes, and as a result, they are likely to finance studies of scientists whose research efforts support their interests. The beef industry, for example, might not fund scientific investigations to find connections between high intakes of beef and the risk of certain cancers. On the other hand, the beef industry might be interested in supporting a team of scientists whose research indicates that a high-protein diet that contains plenty of beef is useful for people who are trying to lose weight.
follow up
The results of one study are rarely enough to gain widespread acceptance for new or unusual findings or to provide a basis for nutritional recommendations. Thus, the findings obtained by one research team must be supported by those generated in other studies. If the results of several scientific investigations conducted under similar conditions confirm the original researchers' conclusions, then these findings are more likely to be accepted by other nutrition scientists.
Reviewing Human Subjects Research Designs
Scientists must follow U.S. government guidelines when performing research involving human subjects. Before conducting this type of research, scientists must have the study design scrutinized and approved by their institution's human subjects review committee. To pass the review, a study generally should avoid causing physical and psychological harm or discomfort to subjects beyond that which may be encountered in daily life or during a routine physical examination. Furthermore, the study should treat each subject fairly and protect subjects' privacy. Before participating in the study, adult subjects must provide legally obtained informed consent indicating they are aware of the benefits and risks of the research effort and are willing participants.
Reviewing human subjects research designs
Scientists must follow US guidelines when performing research on humans. They must have the study design scrutinized and approved by their institutions human subjects review committee. To pass the review a study should avoid causing physical and psychological harm or discomfort. Study should treat each subject fairly and protect privacy. Adult subjects must provide legally obtained informed consent indicating they are aware of the benefits and risks and willing participants
Limitations of Epidemiological studies
Studies cannot establish causation, that is whether a practice is responsible for an effect. When 2 different natural events occur simultaneously within a population it does not necessarily mean they are correlated. A correlation is a relationship between variables. A correlation occurs when 2 variables change over the same period.
The Federal Trade Commission (FTC) enforces
The Federal Trade Commission (FTC) enforces consumer protection laws and investigates complaints about false or misleading health claims that appear on the Internet. For information to help you evaluate nutrition and health-related claims
What is complementary and alternative medicine?
The use of herbal products and other dietary supplements to treat disease or promote good health is an aspect of complementary and alternative medicine. CAM includes practices and products that are not accepted by the physicians and other health care providers. In 2007 38% of American adults and 12% of American children used CAM therapies including chiropractic manipulations, homeopathy, naturopathy, and massage therapy. Some Cam practices are gaining acceptance because of scientific support. Ex. Unfriendly bacteria can overpopulate the large intestine when a person takes antibiotics for infection. Overgrowth of bacteria can cause cramping and diarrhea. Some physicians recommend probiotics in yogurt.
Many variables can influence the outcome of an experimental study.
Therefore, scientists who want to determine the effect or effects of a single variable, such as chemical X intake, need to control the influence of the other variables. All other conditions, including availability of water and room temperature must be the same for both groups of mice. If researchers design an experiment in which they fail to control variables that are not being tested the findings are likely to be unclear or inaccurate.
Popular sources of nutrition information, such as magazines and the Internet, generally do not subject articles or blogs to peer review or other scientific scrutiny, and as a result, they may feature faulty, biased information.
a health news column in a popular magazine may report findings from a few nutrition journal articles that support the use of garlic supplements for reducing blood cholesterol levels. However, you may conclude that the column is biased if it excludes results of other studies that do not indicate such benefits. You can often distinguish a peer-reviewed scientific journal from a popular magazine simply by looking at their covers and skimming their pages. Compared to scientific journals, magazines typically have more colorful, attractive covers and photographs, and their articles are shorter and easier for the average person to read
