Table 3: Summary of methodology.

StepGeneral activitiesSpecific activities

Step  1Configuration of a working group Three operators skilled in clinical nutrition:
(i) one operator acting as a methodological operator
(ii) two operators participating as clinical operators

Step  2Formulation of the revision questionEvaluation of the state of the art on metabolic and nutritional correlates of sarcopenia and their nutritional treatment

Step  3Identification of relevant studies on PUBMED(a) Definition of the key words (sarcopenia, nutrients, and dietary supplement), allowing the definition of the interest field of the documents to be searched, grouped in inverted commas (“…”), and used separately or in combination;
(b) use of the Boolean (a data type with only two possible values: true or false) AND operator that allows the establishments of logical relations among concepts;
(c) research modalities: advanced search;
(d) limits: time limits: papers published in the last 20 years; humans; languages: English;
(e) manual search performed by the senior researchers experienced in clinical nutrition through the revision of reviews and individual articles on sarcopenia in elderly published in journals qualified in the Index Medicus

Step  4Analysis and presentation of the outcomesThe data extrapolated from the revised studies were carried out in the form of a narrative review of the reports and were collocated in tables.