Robert Weisell is the Nutrition Officer responsible for the macro- and micronutrient requirements in the FAO Nutrition Planning, Assessment and Evaluation Service.
In 1995 I wrote an article on a topic similar to that of this article for the fiftieth anniversary issue of Food, Nutrition and Agriculture (Weisell, 1995). The title was "Expert advice on energy and nutrient requirements: an FAO tradition", and it basically described the history of the expert consultations on macro- and micronutrient requirements from the time of FAO's founding. This article is returning to the subject, largely as a result of the recently completed Expert Consultations on Energy in Human Nutrition, and Protein-Amino Acids in Human Nutrition, at which the topic of requirements was emphasized. However, the prescribed process of conducting expert consultations will be scrutinized and questions raised as to whether the current modus operandi is still relevant to the realities of today.
One of FAO's first tasks upon its founding - and perhaps partly the impetus behind its founding - was to address the catastrophic food shortage in Europe in the aftermath of the Second World War. However, in assessing whether or not food supplies are adequate to meet a population's nutritional needs, it is necessary to know human energy and nutrient requirements. Such knowledge aids not only the mobilization and distribution of emergency food aid but also the monitoring of nutrition programmes and planning of development activities in general.
In 1948, the newly established FAO Standing Advisory Committee considered that "the problem of assessing the calorie1 and nutrient requirements of human beings, with the greatest possible degree of accuracy, is of basic importance to FAO" (FAO, 1950). As a result, a gathering of experts was convened in September 1949 to address the issue of calorie needs. In the foreword of the report of this meeting, the Director of the Nutrition Division, Dr Wallace R. Aykroyd, observed that "even tentative recommendations would be of immediate practical value to FAO but also to its member countries". The recommendations would also be of value to "nutrition workers and others concerned with the problems of food requirements" (FAO, 1950). These quotes from Dr Aykroyd's foreword highlight two important points, which remain valid today. One is that the recommendations are very likely tentative, i.e. subject to change as more scientific information accumulates. One cannot wait until all data are available before acting and, once recommendations have been made based on the data available, there should then be no reluctance to revise those recommendations on the basis of new data. Secondly, Dr Aykroyd recognized that "nutrition workers", most likely without an in-depth knowledge of nutrition, would refer to the recommendations. Such is the case today and this has implications on how the recommendations are presented.
The first Committee on Calorie Requirements made a number of points that are pertinent today. The requirements were intended for groups of people rather than individuals, and the committee established the principle that "an average requirement can never be compared directly with an individual [requirement]" (FAO, 1950). The first committee offered the rule of thumb that if the person "is in good health and calorie balance, that is, neither over nor underweight, then he or she is consuming food according to his or her calorie requirements" (Ibid). Early committees had the insight to add the notion of maintaining an adequate level of energy expenditure, thus recognizing that activity was important and that the requirements were not equated with a minimum, survival level (FAO, 1965).
By the 1960s, the scientific community had begun to recognize the close link between energy and protein metabolism and requirements and that neither could be considered in isolation from the other
The first committee also noted that recommendations should be adjusted to accommodate individual needs and conditions and cautioned that nutrition and health experts within countries should take local conditions into account when applying the requirements. This need to exercise judgement in interpreting and using requirement values is still valid today, yet it is a difficult concept for users to understand and apply. Another issue addressed by the first committee was the fact that whereas the recommended requirement values were determined at the physiological level, the country's food supply is often estimated at the retail level and a certain amount of adjustment is therefore required when comparing the two levels (FAO, 1950). To assist in the assessment of calorie needs, they called upon food economists; however, this collaboration has never been fully realized over the years. Although initially the secretariat was assigned the mandate of preparing a chapter or section of the report that would address the practical applications of the requirements, this solution was not found to be satisfactory.
The subsequent committees also emphasized the important relationship between calories and other nutrients and stressed that sufficient calories should not necessarily be equated with adequate nutrition. The first FAO committee that convened to determine protein requirements was held in 1955. The most crucial difference between the determination of energy requirements and protein requirements is that energy requirements must be presented as an average, i.e. it was "normal" for half the homogeneous population to be below the mean and half above, while protein requirements and those of other nutrients were presented at the top end of the normal distribution of intakes or needs, at a level termed "safe level of intake". Quality of protein, in addition to quantity, was also an important consideration.
By the 1960s, the scientific community had begun to recognize the close link between energy and protein metabolism and requirements and that neither could be considered in isolation from the other. Because of this close relationship, the next expert group meetings on energy and protein were held jointly in 1971 with the specific charge "... to examine the interrelationships between requirements for energy and proteins and to recommend means for the integration of requirement scales for energy and proteins, if that were feasible" (FAO/WHO, 1973). Soon after the report of this consultation was published in 1973, it became apparent that problems had arisen in the application of the report's findings, and in 1975 FAO and the World Health Organization (WHO) convened an informal gathering of experts (a subgroup of the 1971 expert consultation) specifically to address this issue (FAO, 1975). Of particular note was the inappropriateness of devising requirements for a healthy population while it was known that a large proportion of the world's populations were not healthy.
A second informal gathering was held in 1978 to continue the work begun in 1975 (WHO, 1979). In particular, the following areas of uncertainty were identified:
The above questions and gaps in knowledge identified prompted the experts to question the practical relevance of the accepted criteria by which requirements were determined, i.e. nitrogen balance for protein and the maintenance of body weight for energy. Speculation arose as to the possible level of adaptation to low protein intakes without accompanying disadvantages while allowing nitrogen balance and normal growth. It was also noted that weight maintenance, the criterion of energy balance, does not take into account whether the weight is optimal or whether there is an allowance for physical activity. As a result of the concerns and gaps noted by the 1978 group, FAO and WHO were advised that a full-scale expert consultation was warranted. This meeting occurred over a two-week period in October 1981 at FAO in Rome.
One significant departure of the 1981 expert group from that of the 1971 expert group was the rejection of the concept of a reference man or woman. The 1971 group defined such persons as "arbitrarily selected convenient starting points for extrapolation ... and ... not intended to suggest ideal standards. They were originally chosen as being representative of groups of men and women whose food consumption and energy expenditure had been carefully studied" (FAO/WHO, 1973). The 1981 group found this concept too restrictive and not reflective of the wide range of both body size and patterns of physical activity. Previous expert groups had expressed a preference for basing energy requirements on actual expenditure data because energy intake in many parts of the world is insufficient to maintain desirable body weights or optimal levels of physical activity. However, the data were lacking. By 1981 sufficient information existed to use energy expenditure as the determinant for energy requirements of all age groups except for children under ten years. This allowed the basal metabolic rate (BMR) to be established as the basis for expressing energy requirements. The proposal of this new methodology for calculating energy requirements led to the need for substantial research to be carried out after the expert consultation. This was the major reason for the delay in publishing the consultation's report. During the four-year interval, a complete database of BMR measurements, mostly gleaned from the scientific literature, was established, as was information on activity patterns in various societies and energy expenditure levels for various tasks.
Perhaps more than with previous expert consultations on energy, the 1981 consultation initiated a wide-ranging agenda of research in energy requirements.
The global scientific community has embraced these "FAO/WHO recommendations", such that they often serve as the reference point for the requirements produced by others. Their influence goes beyond the values themselves by also influencing research agendas and methodologies
One study, sponsored by the Danish International Development Agency (DANIDA), assessed the fulfilment of the energy and protein requirements of poor children on indigenous diets in Guatemala, Jamaica and Thailand (UNU, 1984). There is also little doubt that the development and expansion of the doubly-labelled water technique (DLW) for determining total energy expenditure was a result of the 1981 expert consultation and its recommendations (see the article by Dr Shetty on page 5).
Seven years after the 1981 expert consultation, the chairperson, Professor John Waterlow, suggested to FAO and WHO that sufficient new data and concerns about some of the 1981 conclusions had arisen to warrant an update. The International Dietary Energy Consultancy Group (IDECG), in which FAO was a participant, also urged FAO and WHO to hold an expert consultation on energy and protein. However, in the absence of progress by the UN agencies, IDECG organized a workshop to review many of the issues and new developments related to energy and protein requirements. The proceedings of this workshop were published in the European Journal of Clinical Nutrition.
By 2000, FAO and WHO decided to review again the energy and protein requirements in two separate but closely linked meetings. The expert consultations were preceded by a workshop that reviewed the unresolved issues and, drawing heavily from the proceedings of the 1994 London IDECG workshop, prepared background documentation for the expert consultations.
The Joint FAO/WHO/United Nations University (UNU) Expert Consultation on Energy in Human Nutrition was held at FAO headquarters in Rome from 17 to 24 October 2001. The new concepts and changes coming from the expert consultation include:
Over the years the technical issues addressed by expert groups have evolved and changed. But so too has the process of addressing the scientific issues. Article VI of the FAO Constitution defines the procedure and protocol issues for reviewing scientific and technical issues and making recommendations. Expert group meetings are convened under a number of titles ("committee", "expert committee", "ad hoc expert committee", "expert consultation", etc.), comprising individuals who are appointed to serve in their personal capacity, i.e. not representing the official position or views of their respective governments. These expert groups can be established by the FAO Conference and Council or, at times, at the discretion of the Director-General (FAO, 1992).
A topic such as requirements takes on an enhanced economic and political importance, resulting in attempts to influence the process outside the normal consultation process
For a number of years, FAO and WHO relied on the FAO/WHO Expert Committee on Nutrition to provide overall technical advice and to formulate the work programmes for both organizations, including recommendations for convening expert groups to address specific nutrition issues, such as requirements. However, the influence of this advice on nutrient requirements has far exceeded its original purpose of determining the requirement levels for guiding action. The global scientific community has embraced these "FAO/WHO recommendations", such that they often serve as the reference point for the requirements produced by others. Their influence goes beyond the values themselves by also influencing research agendas and methodologies. As already mentioned, this expanded influence was predicted by Dr Aykroyd in his foreword to the first report on calorie requirements.
There is often a misunderstanding regarding the status of the report itself. Although a report represents the experts' opinion and recommendations to FAO and WHO on a selected technical topic, it is often assumed automatically to represent the policy of the Organizations. However, this is not the case. It is presented to them for their consideration, much like a consultant's report.
In reviewing the experience of each successive consultation, a number of changes can be noted. The geographical representation of the experts has expanded over the years. Even as late as the 1971 Joint FAO/WHO Ad Hoc Expert Committee on Energy and Protein Requirements, only two of the thirteen experts were from the developing world (India and Thailand) and one from the Eastern bloc, while the rest were from North America and Europe. Today, a much broader geographical representation is required by the Organizations. The length of time between convening the consultation and publishing the report has increased - the reasons for the prolonged period before the 1985 report was published were presented earlier in this article. There has also been an increasing need to amend and clarify the reports following their publication, e.g. the 1975 and 1978 informal gatherings.
The evolved procedure for an expert meeting consists of the following steps:
This process worked reasonably well during the first few decades, i.e. the 1950s and 1960s. The science of nutrition was less complicated, and fewer articles, journals, researchers and countries were involved. Today, the literature is vast with strongly opposing positions on certain topics. Equally eminent scientists can disagree on a topic where one will not accept results that the other believes are scientifically sound. Differences in opinion arise over the study protocol and the experimental design. This has led to instances where the conclusions and recommendations have been challenged after the report has been published, and the experts themselves express concern over some of those conclusions. This occurred with the 1971 ad hoc expert committee meeting, which was followed by two informal gatherings of experts in order to address unresolved issues. An increased number of crucial issues that are not foreseen may become apparent only during the meeting itself. Today, even a topic such as requirements takes on an enhanced economic and political importance, resulting in attempts to influence the process outside the normal consultation process. An increasing number of interested players strive to be participants, demanding an input, which can influence the final conclusions.
The selection of experts is another area where attention is needed. There is an increased call for more transparency and openness in the selection of the experts. For other types of meeting within FAO, a call from the Web for résumés has been made and a prescribed list of criteria for selection adopted. There are advantages to this process but there is also the danger of ending up with experts who may be well versed in selected aspects of the topic but not sufficiently familiar with the bigger picture. It is also true that a highly regarded scientist may not perform well in a meeting forum - such traits are difficult to detect from résumés. More-over, however the experts are selected, there is now a requirement for the scientist to sign a declaration of conflict of interest.
Over recent years FAO and WHO have attempted to improve the process by preparing more thoroughly for the deliberations. Normally, a consultant or consultants familiar with the topic work with the secretariat in preparing the agenda and background paper topics. Pre-consultation meetings have been held to allow the background papers to be discussed among those scientists most renowned in the relevant fields. However, scientists who prepare these background papers consider it essential that their background papers are eventually published in a peer-reviewed journal. Although the role of the rapporteur remains vital, note-taking and preparation of the draft are complemented by inputs from consultants.
Pitfalls exist in prescribing realistic revisions to the process for reviewing the energy and nutrient requirements and other scientific issues because the final approval for any change will have to come from the member countries themselves. However, there are a number of options that could be considered. One is to link the process more closely with ongoing national review pro-cesses - a current example is the Institute of Medicine's Food and Nutrition Board review of macronutrient requirements, which involves considerable time and money.
The United Nations would not necessarily adopt the same numbers as a national review but the same literature would be reviewed. The review itself must be a more continuous process by the secretariat, not a stop/start process as has been the case. One mode might be to commission a scientist active in a particular field to prepare annually a review of what has occurred in the scientific aspects of that field over the year. In that way the secretariat could form a more informed opinion as to the need to review the topic. Perhaps more reliance should be given to using smaller, more frequent informal meetings where protocol requirements could be relaxed.
FAO, in common with its sister organization WHO, is confronted with the task of adapting the established working procedures to fit the realities of today. Selecting qualified experts who will incorporate the perspectives of FAO's many member countries presents a challenge. Creating a more continuous review process is another. Governments and the private sector find there are increased political and financial stakes associated with a pronouncement from FAO on a nutritional topic and therefore seek to be included in the debate. Regardless of the changes made, the scientific community and member countries will continue to look to the expert groups to provide the definitive pronouncements on nutrient requirements and their use. Providing information of high scientific quality, which meets the needs of many parties throughout the world, remains an on-going challenge.
1 During the early years of FAO and within the general scientific community, energy was referred to as "calorie", the unit then applied to expressing energy. In fact, the correct unit is "kilocalorie" and increasingly the convention is to use kilojoules (kJ), where 1 kilocalorie equals 4.1868 kJ.
bibliography
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FAO. 1992. Basic Texts of the Food and Agriculture Organization of the United Nations, Volumes I and II. Rome.
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