What is a serious scientific study

It is a great challenge in this era of over-communication to separate the wheat from the chaff. 

How can we deal with so-called scientific studies that show contradictory findings?
Indeed, regarding wine, one reads contradictory things:
It is healthy when consumed regularly, and with moderation. And wrongly informed people are saying  :It is bad for our health...
What approach can we adopt to reach a just and balanced conclusion?
For the French non profit organization : " les 4 Vérités sur le Vin" or the 4 Truths about wine, we have adopted a selection method which, according to high level scientists, is very strict. We have done this because we are talking about a serious issue, our health. 
Here is our selection method for the scientific papers on which we base our ideas and theories:
The paper has to be published in a journal that has impact factor of at least 5.
The journal must be part of the top 10% in its domain (ex.: cardiology or surgery).
What is the Impact Factor ?
The Impact Factor is a ranking system determined by an independent structure (Thomson Scientific) every year. It gives the ranking of the scientific journals that are the most quoted in other journals. 7,000 scientific journals are ranked every year.
What is the ranking in a specialization ?
It is a ranking, always determined by an independent organization, in each specialization, (ex.: Cardiology, Radiology, Surgery or Oncology). 
Selecting only journals ranked 5.0 or more and that are among the top 10 journals of that specialization is the guarantee that our sources are reliable and serious.
What about papers which are not published in journals without any Impact Factor rating or a very low one ?
Even if such a study is mentioned by the French or American Health Ministry, we cannot give it any scientific credit. They are often moral, philosophical, or political opinions.

As examples : Impact Factors range from 63 to 0,035 which is an incredible gap for scientists.

You want to see an example of ranking pages ?

See just below :

New England J Med means New England Journal of Medicine

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author : Fabrice Delorme