e-Library of Evidence for Nutrition Actions (eLENA)

eLENA content

There are three categories of nutrition intervention in the WHO e-Library of Evidence for Nutrition Actions (eLENA):

  • Category 1: interventions for which extensive research has been conducted and guidelines exist that have been recently approved by the WHO Guidelines Review Committee (GRC);
  • Category 2: interventions for which there is extensive research but no recent GRC-approved WHO guidelines;
  • Category 3: innovative interventions that are not yet ready for scaling up.

For each nutrition intervention, eLENA compiles a number of documents and content types.

WHO documents

The development of global guidelines and recommendations is one of WHO’s core functions. Where available, a link to the full WHO document or guideline will be presented for each nutrition intervention title, along with additional information on the status of the guidelines if they are in the process of being developed or revised. For each title, it will also be indicated if the guidelines have gone through the Guidelines Review Committee process.

Biological, behavioural and contextual rationale

The biological, behavioural and contextual rationale statement explains the biological basis for each nutrition intervention. These short summary articles also take into consideration the various behavioural and contextual factors that may impact the effectiveness of the intervention. This information is useful in evaluating potential nutrition interventions for a specific context. If you are interested in submitting a biological, behavioural and contextual rationale, please use the “How to contribute” page.


The evidence to support the guidelines is in the form of systematic reviews. This section includes links to systematic reviews from the Cochrane Library as well as other examples of those published in peer-reviewed journals.

The evidence section also provides access to related clinical trials registered in the International Clinical Trials Registry Platform.

This section will be updated on a continual basis, however, due to space limitations not all published evidence on a given topic will be profiled.


Commentaries are summaries of the systematic reviews that currently exist on each topic. They also provide opinion on the relevance of the evidence to under-resourced settings and give practical advice on the implementation of the intervention.

Commentaries are independent articles, written by nutrition experts, programme planners and/or field staff. The eLENA team at WHO is responsible for inviting the commentaries to complement the evidence currently available. If you are interested in submitting a commentary, please use the "How to contribute" page.

Content for different categories of intervention

Interventions that include newly developed WHO guidelines (Category 1 interventions) will generally not include supplementary content such as a biological, behavioural and contextual rationale or a commentary. However, interventions that include evidence in the form of a systematic review (Category 2 interventions) and interventions with only minimal or no available evidence (Category 3 interventions), will generally include both a biological, behavioural and contextual rationale as well as a commentary.