Background
Trans-fatty acids (TFAs) are unsaturated fatty acids with at least one double bond in the trans configuration. Dietary TFAs primarily originate from two sources: industrially produced TFAs (IP-TFAs) and ruminant TFAs (R-TFAs). WHO recommends limiting TFA intake to below 1% of total energy consumption to reduce cardiovascular risk (1). IP-TFAs are mainly formed through partial hydrogenation of vegetable oils, as well as through refining, deodorizing and deep-frying. Foods made with partially hydrogenated oils (PHOs) such as some margarines, shortenings, baked goods and fried foods are the major dietary sources of TFA. R-TFAs occur naturally in meat and dairy from biohydrogenation of fatty acids by microorganisms in the rumen of ruminant animals (e.g. cows and sheep).
In 2018, WHO called for the global elimination of IP-TFA and introduced the REPLACE action framework to guide countries in removing IP-TFAs from the food supply (2,3). WHO's recommended best-practice policy alternatives are: 1) a mandatory limit of 2 g IP-TFA per 100 g total fat in all foods; and 2) a ban on the production or use of PHO as an ingredient in all foods.
Some countries have requested WHO's guidance on analytically differentiating IP-TFAs from R-TFAs. No universally accepted laboratory method currently exists to directly distinguish the two; however, in 2021 the European Commission's Joint Research Centre (EC-JRC) proposed a decision-tree-based approach to estimate IP-TFA content in foods containing mixtures of PHOs, refined oils, frying oils and ruminant fats (4). This approach relies on measuring butyric acid (C4:0) or C18:2 cis-9, trans-11 (9c,11t-CLA) and applying conversion factors derived from milk and tallow fatty-acid profiles to estimate R-TFA content, from which IP-TFA can be inferred by difference.
Following a 2024 WHO roundtable consultation, which reviewed the EC-JRC approach and identified the need to assess whether its conversion factors could be applied to food products outside the European region, WHO issued a public call for data on the fatty acid composition of bovine milk (submissions closed on 15 July 2026). This global dataset will provide the evidence base needed to assess the applicability, and any necessary adaptation, of conversion-factor-based approaches across different regions and production contexts.
To take this work forward, WHO is establishing an Expert Group to review the data collected through this call and to provide advice on a scientifically sound and practically feasible approach for estimating IP-TFA content in foods with mixed TFA sources.
Information for candidates
Qualifications
Successful candidates should meet most or all of the following qualifications:
- An advanced degree and demonstrated expertise in one or more of the subject matter areas listed below
- Relevant scientific publications in peer-reviewed journals
- Leadership, or invited participation, in national or international scientific bodies, committees or other expert advisory bodies pertinent to the scope of this work
- Practical experience with fatty acid analysis and/or interpretation of food composition data
- Ability to contribute to the preparation of scientific documents and to work in an international environment with scientists from various disciplines
- Good knowledge of the English language, both written and oral
Expert functions
The Expert Group will perform the following functions:
- Review and analyze the global fatty acid composition data on bovine milk and milk products submitted through WHO's public call for data
- Assess the applicability of the EC-JRC decision-tree / conversion-factor approach (4) to the global dataset, including any regional variability in milk fat composition that may affect conversion factors
- Advise WHO on a scientifically robust and practically feasible approach for estimating IP-TFA content in foods containing mixed R-TFA and IP-TFA sources, for use in monitoring compliance with TFA policies
- Identify data gaps or limitations in the current evidence base and recommend, if needed, further data collection or validation work
- Contribute to the preparation of technical guidance summarizing the recommended estimation approach
Subject matter expertise needed
The Expert Group will consist of a multidisciplinary group of experts, each with expertise in one or more of the following relevant domains:
- Analytical/lipid chemistry, particularly gas chromatography (GC)-based fatty acid analysis methods (e.g. AOAC 2012.13 / ISO 16958 | IDF 231:2015, AOAC 996.06, AOCS Ce 2b-11)
- Dairy science and ruminant fat biochemistry, including sources of variability in milk fat composition
- Food chemistry and food composition, particularly of industrially processed fats and oils
- Nutrition science and risk assessment relevant to TFA intake and cardiovascular health and chronic diseases
- Food regulatory science and policy relevant to TFA labelling, limits and monitoring
- Biostatistics/data science, with experience analyzing multi-country compositional datasets
Submitting an application
Interested parties should submit the following documents by email to yamamotor@who.int:
- Curriculum vitae, including
- detailed education background;
- relevant work experience; and
- list of peer-reviewed publications.
2. Completed Declaration of Interests (DOI) form
- The DOI form is available at: https://cdn.who.int/media/docs/default-source/ethics/doi-en-form-blank.pdf?sfvrsn=799d694_9&download=true
- Guidance on completing the DOI form is available at: https://www.who.int/publications/m/item/declaration-of-interests---annex-a
- Code of Conduct for WHO experts is available at: https://www.who.int/publications/m/item/declaration-of-interests---annex-b
3. Signed Confidentiality Undertaking
- The Confidentiality Undertaking form is available at: https://www.who.int/publications/m/item/declaration-of-interests---annex-c
Process for selection of experts
- Each curriculum vitae will be reviewed to assess whether the applicant meets the qualifications and has relevant expertise in the subject matter areas listed above.
- Declaration of Interest forms will be reviewed. Any potential or perceived conflicts of interest disclosed in the Declaration of Interests form will be considered in the selection process, with input from the WHO Department of Compliance, Risk Management and Ethics as needed. For more information, see https://www.who.int/about/ethics/declaration-of-interests.
- In addition to subject matter expertise, the selection of experts will also take into consideration diversity and complementarity of expertise, a balance of genders, and balanced representation from WHO geographic regions, including developing and developed countries.
- Representatives of commercial organizations may not serve as experts. They may be invited to attend part of the meeting as external resource persons, if required, but may not be present at the meeting when recommendations are being formulated.
Selected experts will be invited to contribute only in their individual capacity and will not represent their government, institution or other organization.
Completing this work is expected to take approximately 6 months. Meetings will be held virtually. No honoraria or other forms of remuneration will be provided. All meetings will be held in English only and all documents will be prepared and provided in English.
Applications must be submitted by email to yamamotor@who.int by 8 September 2026 (11:59 pm, CEST, UTC/GMT +1 hour) to be eligible for consideration.
Questions regarding this call for experts should be addressed to yamamotor@who.int.
References
- World Health Organization. Saturated fatty acids and trans-fatty acids intake for adults and children. WHO guidelines. Geneva, Switzerland, 2023.
- WHO plan to eliminate industrially produced trans-fatty acids from global food supply [news release]. World Health Organization; 14 May 2018.
- World Health Organization. REPLACE trans fat: an action package to eliminate industrially produced trans-fatty acids. Geneva, Switzerland, 2021.
- Ulberth, F. and Wenzl, T. Analytical approach for checking the compliance of fats and oils against the regulated limit for industrial trans fatty acids (Commission Regulation (EU) 2019/649), EUR 30767 EN, Publications Office of the European Union, Luxembourg, 2021, ISBN 978-92-76-40304-3, doi:10.2760/102265, JRC125335.