Unit 2 General Principles Of Research In Nutrition

Question 1

What do nutrition scientists actually do in terms of studying nutrition science

Answer 1

They get facts by systematically asking questions and using the scientific method to design and conduct expiriments to answer the question and test for various possible answers

Question 2

What does nutrition monitoring help with

Answer 2

Help researchers assess nutrient status, heath indicators, and dietary intakes of the Canadian population

Question 3

What are the examples of research design

Answer 3

Epidemiological study

Case study

Intervention study

Lab study

Question 4

What is a intervention study

Answer 4

Uses the basic scientific method. When used in health studies it’s called RCT (randomized controlled trials) , whci hard used for testing new drugs

The researches intervene to alter peoples diet.

Have Two groups:
- intervention: make a single dietary change, have the treatment
- control group: continue with regular diet, untreated or has a placebo

Usually called a controlled trials because there a control group

After a time the two groups are compared any any diffence between the two hours is because of the single intervention

Question 5

What is the scientific method

Answer 5

Observation and question

Hypothesis and prediction

Experiment

Results and interpretations

Hypothesis supported:
- theory developed
- new observations and questions

Hypothesis not supported:
- new observations and questions

Then back to start

Question 6

What are the safeguard in intervention studies and why

Answer 6

To reduce possibly of changes be attributed to random chance:

• test groups have to be large enough to reduce effect of random chance influence (30 or more subjects per group)
• random placement of people into the groups to prevent bias
• two groups are compared at start of study to make sure they a similar in factors relevant to the study. They need to match in sex age and ethnicity: ex. If effect of diet on weight loss is tested, members of the two groups need to be similar weight.

Question 7

What is the placebo effect

How is it overcome

Answer 7

Can be found in intervention studies

If ill people are given an inert substance (placebo) and are told its actually medicine, they will report they feel better

Overcome by giving the control group in the intervention study a treatment that very closely resembles the active/actual treatment

Ex. If testing effect of sugar on energy intake , The treatment group is given drink with actual sugar , control is given drink that taste and looks similar but has synthetic sweetener

Question 8

What is the double blind part of intervention studies and why is it used

Answer 8

Used to prevent bias of investigators

Both the patient and investigator are blind/ don’t know if the subjects have the placebo or the active treatment

• if the investigator expects that the treatment will reduce pain in the patient they’ll “observe” a reduction in pain even if treatment is ineffective
• then if the patient sees this bias, as a result the patient could “improve” with the active treatment not because it was more effective but become the investigator said it was
• in the end it’s like the active treatment got another type of placebo effect

Question 9

Double blind studies are the

Answer 9

Gold standard in drug trials or when nutritional supplements are given

Question 10

When can the blinding of subjects not happen

What happens instead

Answer 10

In experiments that involve major diet changes blinding int always possible

But the subjects can still be assessed on a blinded fashion:
- ex. When testing effect of low salt diet on blood pressure the patient knows their diet but the investigator recording the blood pressure won’t because the blood pressure measurement can be subjective

• in case control studies if a patients diet is assesssed the investigators shouldn’t be aware of the patients diagnosis

Question 11

Some Intervention studies are done without a ____

Answer 11

Without a control group, termed uncontrolled

Errors:

• These are less reliables than controlled studies because you can’t be sure if subjects would have responded in the same way if not given treatment
• many conditions clear up without treatment
• assessment of subjects: if BP measured in successive days, it’s goes down. If under stress due to being in doctor office it goes up then goes down as they become less stressed. Uncontrolled trials would show that anything lowers the BP

Question 12

What is good about intervention studies

Answer 12

Can be carried out on healthy subjects to prevent diseases, or on sick ppl to test tratment (clinical study/clinical trial)

Great in showing there there is a cause and effect relation ship between a nutrient variable and disease

Question 13

What is anecdotal evidence

Answer 13

Also called case study

Collecting ancentdoctal evidence is the simplest and least reliable way to study role of diet in disease

Investigator makes inferences of diesease from the previous experiences of one or more individuals

can go wrong:
- women who’s smokes has healthy kid, women who doesn’t smoke has kid with Down syndrome
- observing these isolated cases would suggest that smoking prevents Down syndrome , not good so the same observation should be repeated many times

Can go well:
- many ppl in US reported headaches with specific symptoms after eating in Chinese restaurants
- the cause was mono sodium glutamate (MSG) food additive
- so anectdotal evidence was useful because many similar reports were observed

Question 14

Advantages and disadvantages or anecdotal evidence

Answer 14

Pros:
- like the MSG example, completely new and previously unsuspected relationships can be found
- side effect from new drugs can be uncovered when many reports based on individual patients are collected and a pattern emerges

Cons:
- inherent unreliability because all types of errors can occur

• error of chance: many worker exposed a a chemical get the same type of cancer, this could be chance
• error of bias in the observation: due to the power of suggestion, people are unreliable in describing their symptoms. especially symptoms of headaches and caught pains

Question 15

Overall how is anecdotal evidence used and accepted

Answer 15

Only accepted with lots of caution because many errors.

Provides suggestions for further study but is rarely the basis for firm conclusions

Advertisers use anecdotal evidence to promote products. This is called testimonials where they use personal stories to promote wieght loss diets, foods, or supplements.

Need to be skeptics of ads that rely on anecdotal evidence

Question 16

What are epidemiological studies

Answer 16

The study of the incidence of distribution of diseases and studying their control and prevention in whole populations

Reveals correlation: ex. Country food has more nutrient x and these people suffer less illnesses y (inverse/negative correlation)

Four types of epidemiological studies:
- population
- historical
- case control
- cohort

Question 17

What is a population epidemiological study

Give example

Answer 17

Compare disease patterns with various factors like food consumption on a countrywide basis

Ex.

• want to know relationship between potato consumption and pancreatic cancer
• taking data on the quantity of potatoes eaten in countries A and B and compared it with the occurrence of pancreatic cancer
• observed that people in country A eat twice as much potatoes than B, and that A have double incidence of pancreatic cancer
• on the surface this suggests that potatoes cause pancreatic cancer

Question 18

What are the two problems with the population study with potatoes and cancer in epidemiological studies

Answer 18

Errors in the data:
- closer examination of data shows that A are rich and waste half their potatoes and B are poor and can diagnose half of their cases of pancreatic cancer
- this means both actually eat similar amount of potatoes and similar frequency of pancreas cancer

Confounding variables:
- closer examination of data shows A have more obesity and B obesity is uncommon
- the confounding variable (obesity) might be the factor causing cancer (not the potatoes)

• confouding variables occur with the factor under study and mask the real cause of the disease . Very common for this to happen in diet studies since many things contribute to diet
• more common limitation is the confounding variable

Question 19

Overall what is useful about population studies

Answer 19

Researchers can show association:
- as one factor changes (more potatoes) disease variable changes (more cancer)
- BUT being accosiated doesn’t mean one thing caused the other. Only intervention trial can tell cause and effect

Even if there are errors it can give valuable finding :
- benefit of Mediterranean diet discovered when found that counties that border the Mediterranean have lower rate of heart disease

Question 20

What is a historical epidemiological study

Give example

Answer 20

Taking the history of a disease to reveal clues of the cause of the disease

Useful when there are accurate records of number of people who died from or have a specific health problem

Ex. Relationship between cigarette smoking and lung cancer:
- lung cancer used to be rare, but became more common among men
- increasing trend of lung cancer in men also matches increase in smoking

• increase in lung cancer in women started after the men
• consistent with the fact that women started smoking after men

Question 21

Pros and cons of historical epidemiological study

Answer 21

Historical studies are best compared with population studies

Pros:
- historical studies are based on large populations and involve large changes in disease incidence
- can use as a valuable clue to support a theory

Cons:
- disease stats taken 60 years ago can be unreliable

• confouding variables can cause fake relationships, meaning there can be guilt by association:
• ex. Disease that increased in incidence in the 20th century will be correlated with any lifestyle factor that also changed
• so it gives accosition between factors but not definitively conclusive

Question 22

What are case control and cohort studies in Epidemiological studies generally

Answer 22

In both, looking at individual in a single population instead of making comparisons of different populations

These studies try to explain why particular individuals in a population suffer from certain diseases based on their exposure to factors thought to be related to the disease

Question 23

What are cohort studies specifically

Answer 23

Also called prospective studies

Large number of healthy subjects are asked questions to see each persons exposure to the factors of the study :
- so with diet studies they determine the exposure by either 24hr food recall or by a food frequency questionnaire

• investigators keep track of the subjects over the years until enough of them developed the disease of interest ( ie. The study variable of interest are not manipulated, but actually monitored overtime)
• then the investigators compare the ones that got the disease to those that didn’t, taking into account exposure to the disease causing factors

Question 24

Give an example of a cohort study

Answer 24

Ex 1. Nurse’s health study in the US where 80,000 healthy nurses did survey on health status and lifestyle with a food frequency questionnaire

They were surveyed a gain after 10 year with similar questions and got back a bunch of data about the relation of cancer and heart disease with lifestyle

Ex 2. Relationship between milk product consumption and growth in a cohort of children

Question 25

What is a case control study

Answer 25

Also known as retrospective studies Similar to cohort study but the recruitment of subjects and data collection are done AFTER the disease has developed These study’s are conducted by then looking back in time and the outcome of subjects is already known (thus retrospective) Ex. Men diagnosed with colon cancer (disease already developed) complete a lifestyle survey. Controls are men of similar age and economic background that don’t have colon cancer

Question 26

Errors in cohort and case control studies

Answer 26

The accuracy of diet assessments : - the 24 hour food recall and food frequency questionnaire are prone to error because of inaccuracies in ppl remembering what they ate

Question 27

What is the major challenge in research on lifestyle and disease risk

Answer 27

Most dietary and lifestyle factors are accosiated with one another : - ex. A person who eat a lot of veggies also eats a lot of fibre and nutrients (which are found in veggies) - Healthy people usally eat a lot of veggies, excersize and don’t smoke. This means that finding what factors actually cause or prevent a disease that they have is hard This is also called confounding variables

Question 28

What’s the one rule that applies to all types of epidemiological studies

Answer 28

They all show association, not causation We conclude by saying that diet factor A is associated with disease B. But we can’t say that factor A CAUSES disease B to move from association to causation, we do intervention studies

Question 29

What are animal experiments and studies of disease mechanisms

Answer 29

Animal experiments resemble intervention studies, where the effect of different treatment on disease occurrence is investigated Animals are divided into groups which each get a different treatment , all other things are kept the same , at the end of experiment the animals are examined to determine the effect of the treatment Control group gets no treatment

Question 30

What are the advantages and disadvantages to animal experiments

Answer 30

Two advantage over conducting experiments on humans: - animal experiments can be carefully controlled in terms of diet and environments, because of this all experimental groups are the same except for the experiment variable being studied - for humans it’s hard to control genetics and their history, there’s no guarantee that they’ll follow instructions on diet of lifestyle changes - also, animal experiments allow testing of chemicals at toxic levels, which lets researchers examine the effects on various tissues after death. Like being able to feed animals very high fat diets to determine the effect on their arteries Disadvantages: - results from animal experiments may not apply to humans

Question 31

What is biochemical and physiological studies of diseases

Answer 31

Looking at the biological and physiological mechanisms that lie behind the disease Most studies on cancer use these type of studies

Question 32

What two criteria is establishing facts in nutrition based on

Answer 32

Since no single study or type of study is completely reliable, establishing the facts and being more confident is based on Reproducibility: - diff research groups report the same finding) Consistency: - consistency in the findings using diff methods like findings from population studies being confirmed in both cohort studies and animal experiments

Question 33

Examples of how several methods are used to increase confidence in a conclusion

Answer 33

Role of smoking in lung cancer: - historical evidence shows a role of smoking in lung cancer but by itself this is weak evidence - using case control and cohort studies that show smokers have higher risk of lung cancer than non smokers , animal studies shows that chemicals extracted from cigarette smoke induced cancer in animals , overall increases confidence in the data Salt intake and hypertension (high BP): - both case control and population studies show relation between salt intake and risk of hypertension - interventions studies shows the when ppl reduce salt intake , BP falls - historical evidence shows that in 1950s a drop in mortality rate from stroke happened same time as drop in salt intake - animal studies shows that some rats get hypertension when fed a high salt diet Overall nutrition researchers need clues from a variety of sources and all evidence needs to point in one direction to draw actual conclusions

Question 34

Appraisal of nutrition information: reliability readings

Answer 34

Okay

Question 35

What is a peer review

Answer 35

When research is and journals with high academic standards are published only after they’ve been carefully checked by experts in the area

Question 36

Why do we need to be skeptical of nutrional nutrional information found in media books or websites

Answer 36

This is because magazine and newspapers show the hottest new info, not the best Media also overrates how important some findings are. Ex. They found oat bran lowers blood cholesterol, but oat bran is only one of many things that affect it and not even the most important one A lot of the information they say is accurate but a lot of it is also untrue or unsubstantiated Also scientist leak their findings to reporter before they’re even peer reviewed

Question 37

Overall how do nutritional scientist make sure their stuff is reliable

Answer 37

Use tried and tested research designs to collect data Keep challenging and revising their own theories Then developing new theories that better explain the latest findings in The field

Question 38

Finding of a single study never

Answer 38

Prove or disprove anything , they could give supporting results but rarely ever merit a solid conclusion

Question 39

What do you need to keep in mind to read news stories with an educated eye

Answer 39

- study described should be in a peer reviewed journal. unpublished studies or non credible source may or may not be valid and the reader can’t tell because not reviewed - the news report should state the purpose of study and research methods used to get the data - should clearly define subject of the study (cells or humans). if they are humans the more you have in common with them the more applicable the finding will be for you - they should describe previous research and and put the current research in the proper context - ask yourself if the study makes common sense ex. Even if marginsin fat is heart damaging, do you eat enough of it to have an effect - when the headline is a shocking new “answer “to a nutrition question make sure to read it critically, they might just use that headline to get attention

Question 40

What is fraud or quackery

Answer 40

For financial gains, promoting treatment, devices, or products (like diets) that alter or claim to alter a human condition without proof of safety or effectiveness Quakery comes from quacksalver

Question 41

What characteristics does scientific research have

Answer 41

- scientists test their ideas by conducting properly designed scientific experiments , they report their methods and procedures in detail so others can replicate and verify the finding - scientist recognize the inadequacy of anecdotal evidence / testimonials - scientist who use animals in their research don’t apply their findings directly to humans - they might use specific segments of the population in Their research and when they do, they don’t generalize the findings to all ppl - they report their findings in scientific journals and that finding has to be peer reviewed before published

Question 42

What’s one of the most trustworthy websites to get reliable nutrional info

Answer 42

National library of medicine PUBMED

Question 43

Credible sources of nutrition info

Answer 43

Page 23

Question 44

What questions do you ask to see if a site is reliable

Answer 44

Whos responsible for the site (.gov or .edu are good) Do the names and credentials of the info providers appear and is an editorial board shown? Are links to other reliable information sites provided Is the site updated regularly Is the site selling a product or service Does the site charge a fee to gain access to it

Question 45

What are indicators of sussness in a source

Answer 45

When the stuff was written by someone other than the sender Phrase of “forward this to everyone you know” Say “this is not a hoax” usually means it is Info is shocking or not something you’ve heard ever from legit sources Language is overly emphatic or has capitalized words or exclamation marks No references and if there are they are questionable The message their sending is debunked on websites like quackwatch

Question 46

What are good sources of reliable nutrion information What are the dietitians of Canada

Answer 46

Dietitians DC It’s the professional association of dietitians and they say that nutrition should be part of the curriculum for health are professionals

Question 47

What is the credential that indicates a qualified nutrition expert What are their titles What are protected names

Answer 47

Registered dietitian (RD): - completed a programs of dietetics that’s been approved by the dieticians of Canada - Have diff titles depending on the province/territory - Ex. In Quebec it’s Dt. P and others it’s R.D, P. Dt, R. Dt Diff provinces/territories also have diff protected names like in Alberta that registered dietitian , registered nutritionist, and distorting is only used for poeaple that a registered with the college of dieticians of Alberta

Question 48

What are provincial regulatory bodies

Answer 48

Registration boards that ; - monitor competence of members - protect the public from unsafe or unethical dietetic practice - protect the use of regulated titles like RD - review the professional conduct of members based on complaints and discipline members when appropriate

Question 49

What are dieticians Public health nutritionists Dietetic technicians

Answer 49

Dieticians: - perform many duties in many different setting like food service, reasearch centres, etc. - trained in nutrition, food science and diet planning Public health nutritionists: - dietician or other person with a degree in nutrition that specialized in public health nutrition - deliver nutrition services to people in the community - plan, coordinate,administer, and evaluate food assistance programs Dietetic technician: - helps RD’s in administrative and clinical responsibilities - is educated and trained to work under an RD

Question 50

How can you detect fake credentials

Answer 50

- they need to have a minimum of a bachelors in food science and human nutrition from an ACCREDITED UNIVERSITY (approved by and agency like the dieticians of of Canada or ministries of education - fake nutrition experts get degrees from a correspondence school that gives a correspondence degree (from a 6 month course taken at home) - these schools are diploma mills (selling certificates to anyone who pays the fees, give them degree without them need to actual meet the educational standards

Question 51

Overall what do you do to stay ahead of nutrition quacks

Answer 51

Check the providers qualifications: - look for degrees and credentials (like MD or RD) - look at the reputation of the institutions that gave them those degrees