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A snapshot of the summary - Food components and health
1 Week 1 Basic principles
1.2 Study disign
What are the types of experimental studies and what is it?Intervention studies are the type
Experimental study's are the most powerful. You actually do an interventional experiment.
What are the types of observational studies?
- prospective cohort studies
- case-control studies
- cross sectional studies
- Ecological population based studies
Diet of people is not changed. They are studied in there natural context. It can not lead to hard conclusions only associations.
What is a FFQ?A FFQ stands for food frequency questionnaire
It assess how often you eat certain foods and in what amount.
It is a dietary assessment method
What is a 24 h dietary recall?This is a dietary assessment method.
A dietitian writes down what a person ate in the last 24h (usually performed several times.
What is a food diary?This is a dietary assessment method.
It is written down and weighted what people eat.
Unfortunalty people tend to change there eating habits and loos motivation and forget to write down things.
What are food composition tables?These tables contain information about nutritional content of food, unfortunately they are incomplete and many food products are not listed.
What is a cross sectional study?This is a observational study.
The dietary intake is linked to a health or disease related paramater. This is done at a single moment.
The downside is that you don't now which one came first. (diet coke or obesity)
So there is risk of cofounding
What is a case control study?This is a observational study.
The dietary intake of sick people is compared with the dietary intake of healthy people. So there is a control group. You look in the past with this study with a food frequency questioner.
The advantage is that you can study rear diseases.
The disadvantage is that there could be bias and cofounding.
What is a cohort study?People are flooded for a long time and when they get sick later in life it is coupled to the things they awnserd in the FFQ.
This is the most powerful observation study.
they relay on FFQ
Cofounding can happen
What is a intervention study?You don't just observe you change something. So you intervene
2 groups are made one who gets the treatment and one who gets a placebo. You measure the hanges that happen before and after the treatment.
advantage: you have avoidance without cofounding and bias.
disadvantages: If you wand to see if people get have to follow them for many years.