You get it?- Deciphering the research

Twenty-five years ago it would have been a rare occurrence to find a dietary health-related study in a scientific journal making front-page news. Now, rarely a day goes by without the media reporting on the findings from yet another breaking dietary study. Public interest in the safety, quality and effectiveness of food and supplements has increased dramatically. Consumers want to know the whats and whys before buying.
Unfortunately more and more frequently the media coverage of these individual studies result in consumer confusion not education. Almost by definition, much of the information involved in these single studies is preliminary, not conclusive and therefore not a strong basis for change in public behavior. These studies, and the news coverage that follows them, do however help raise public awareness of key nutrition, health and food safety issues, if, and that is a big IF they are written in enough context to enable the average person to assess the information appropriately.
As a consumer being influenced by these studies it is important to understand that new research studies published in scientific journals should be viewed as discussions among scientists. In these discussions, almost no one gets to have the final word, as it's rare that a study provides a final, complete answer. Publishing research allows researchers to obtain input on their work, which not only confirms or contradicts their results, but also adds to the body of literature on a subject and helps shape future research.
Keeping this in mind, a major step towards deciphering, interpreting and making educated choices surrounding a study is to understand research practices and methods.
There is a hierarchy of scientific evidence. From most reliable to least it looks something like this:
· multicenter, randomized control clinical trials
· longitudinal prospective cohort studies
· case/control studies
· case studies
· anecdotal studies

Each type of these studies has its advantages and disadvantages.
Clinical trials are the 'gold standard' of research studies. They are typically experiments conducted on human subjects to evaluate the benefits and risks of a given treatment. In clinical trials, treatment groups must be randomized, a control group is required and investigators must be blinded; also the sample size needs to be large enough to allow for differences to be detected.
Advantages:
· Study conditions are at least partially controlled.
· Because of the above, cause-and-effect relationship can be observed.

Disadvantages:
· Challenges involved in maintaining an adequate number of participants.
· The extraordinary costs of conducting such large-scale studies.

Example of a clinical trial- The ongoing Women's Health Initiative, which recently reported its findings on the risks of taking hormone replacement therapy that combines estrogen and progestin.

Cohort studies are observational examinations that compare the outcome of one group that is exposed to a potential hazard or disease with the outcome of another group that is not exposed.
Advantages:
· They focus on hazard exposure before a disease develops.

Disadvantages:
· They require a large number of subjects.
· The follow-up period must be lengthy in order to give time for diseases to develop.
· They are expensive.

Example of a Cohort study- Nurses' Health Study, which recently released a follow-up report on body mass index and its relationship to stroke and heart disease.

Case/control studies are observational in nature. They focus on the subjects who have already developed a certain disease. Researchers then compare the afflicted participants' past exposure to suspected risk factors with the exposure of controls who do not have the disease.
Advantages:
· Useful for identifying rare exposures that may be important causes of disease.

Disadvantages:
· The design is subject to many potential biases.

Case Studies are detailed analysis of persons or groups and usually focus on social, psychological or medical phenomena.
Advantages:
· They serve as catalysts for critical thinking and quantitative questioning.

Disadvantages:
· Not considered as scientifically rigorous as other forms of research.

Anecdotal studies provide information from personal experiences but are not based on fact or proper study design.
Advantages:
· Many similar anecdotal reports may spur on future research.

Disadvantages:
· The results of anecdotal studies are not reliable.

It is also important to remember that nutrition research involves the unique component of recording of dietary intake. Researchers use several methods to obtain this vital data: food records, food-frequency questionnaires, 24-hour recall and diet histories. This component of nutrition research is a challenge as it is common for subjects to under-report their dietary intakes, so it is critical that researchers diligently validate the intake methodologies of the study for the most reliable results.

Questions to Ask.
The questions to ask when reviewing a scientific study or an article reporting on one.
1) What are the inherent limitations (see disadvantages above) of the study and is the type of study appropriate for what the researchers are trying to find out?
2) Is the sample size appropriate for the study?
3) What is the real and statistical significance of the results and to whom do they apply?
4) How do these results compare to those of other studies on the subject?
5) Are the conclusions supported by the data and are they related to the purpose of the study?
6) How was the research funded? This does not always mean there will be a bias; a good study should be able to stand on its own merit regardless of who supported the research. It will more then not dictate what is actually studied rather then the outcome.

With all of the above in mind, wading through all the information that the public is currently being fed is still no easy task; an open mind and diligence are key to finding the most recent version of the truth possible. Always try to put what you read into context, what may seem like a life-altering study today may turn out to be just the opposite tomorrow. That is the nature of research and what makes the journey so exciting.