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close this bookActivity, Energy Expenditure and Energy Requirements of Infants and Children (International Dietary Energy Consultative Group - IDECG, 1989, 412 pages)
View the document(introductory text...)
View the documentIntroduction
Open this folder and view contentsEnergy requirements in normal infants and children
Open this folder and view contentsLow energy intakes and growth velocities of breast-fed infants: Are there functional consequences?
Open this folder and view contentsMethods to assess physical activity and the energy expended for it by infants and children
Open this folder and view contentsEstimation and validation of energy expenditure obtained by the minute-by-minute measurement of heart-rate
Open this folder and view contentsAssessment and significance of body composition in infants and children
Open this folder and view contentsTotal energy expenditure of free-living infants and children obtained by the doubly-labelled water method
Open this folder and view contentsReference data for total energy expenditure in early infancy
Open this folder and view contentsBasal metabolism of infants
Open this folder and view contentsEnergy cost of various physical activities in healthy children
Open this folder and view contentsThe energy requirements of growth and catch-up growth
Open this folder and view contentsEnergy cost of communicable diseases in infancy and childhood
Open this folder and view contentsEnergy-sparing mechanisms: reductions in body mass, BMR and activity: their relative importance and priority in undernourished infants and children
Open this folder and view contentsThe desirable upper limits of energy intake in childhood: Short- and long-term consequences
Open this folder and view contentsLong-term developmental implications of motor maturation and physical activity in infancy in a nutritionally at risk population
Open this folder and view contentsTemperament, activity and behavioral development of infants and children
Open this folder and view contentsThe cultural regulation of infant and child activities
Open this folder and view contentsShort- and long-term effects of low or restricted energy intakes on the activity of infants and children
Open this folder and view contentsThe relationship between undernutrition, activity levels and development in young children
View the documentIndicators for the extent to which energy requirements are being met in infants and children
View the documentImplications of new knowledge for recommendations of energy intakes
View the documentImplications of new knowledge for the prevention and treatment of PEM in infants and children
View the documentImplications of new knowledge for the prevention and treatment of obesity in infants and children
View the documentNeeds and priorities for research and action from the physiological point of view
View the documentNeeds and priorities for research and action from the behavioral point of view
View the documentNeeds and priorities for research and action from the point of view of policy
View the documentList of participants

Needs and priorities for research and action from the point of view of policy

(Discussion leader R.C. WEISELL, rapporteur N.S. SCRIMSHAW)

Users of the FAO/WHO/UNU 1985 report on energy and protein requirements wishing to make an estimate of the energy requirements of a certain population have to make a number of assumptions and choices. Many policy makers among them would prefer to be given a simple number to use or misuse, and get frustrated at having to make assumptions and choices.

Another problem is that policy makers often have to think in terms of food needed for a particular population. Besides estimates of dietary requirements this also involves estimates of food lost and food wasted. Those amounts are generally large, typically somewhere between 10 and 40%, and estimates of this proportion are very imprecise. Slight adjustments of what are believed to be the physiological requirements therefore appear relatively unimportant.

Recommendations of changes in requirements always cause some confusion; they therefore have to be well-founded. Policy makers operate with very rough estimates which are codetermined by political considerations. One nation, for instance, claims to need food imports based on a per capita requirement of 2500 kcal/d, which donor agencies find too high. Nutritionists should be able give advice in such a situation.

Many policy makers have now accepted the general assumption that, under most circumstances, when energy requirements are met, needs of other nutrients are met as well. Several participants at the workshop expressed doubts about the general validity of this assumption and suggested that the situation might be different for well-nourished and malnourished children and when infection is present. If so, these would become factors to be considered when making policy decisions.

Theoretically, food aid and food supplements should be targeted at those who need them most. In practice, food is often distributed indiscriminately in a certain geographic area, because it is too difficult to select those in greatest need and then to ensure that they are the ones who get most or all of it.

Traditionally, nutritional requirements have been discussed and defined by experts at meetings lasting a few days. This may not be the best method of systematically taking into account large amounts of complex research results. More frequent reviews by small working groups who prepare position papers before the official expert consultation takes place, might be useful. For energy requirements, IDECG should play a role in such preparatory work by small groups.

The extent to which other nutrients may have an effect on energy requirements is hard to establish. Energy and iron deficiency are both frequent and often associated, and the symptoms they produce are sufficiently similar to make it difficult to determine which of the two is more limiting in the diet. From a physiological point of view, regulatory mechanisms appear to be related primarily to energy. This seems to pose no major problems as long as energy demands are covered. When this is not the case and regulatory mechanisms are no longer able to function, other nutrients may become deficient by association. Changes in life style can affect energy demand and, with it, the intake of other nutrients.

Policy makers are interested in the relationship between energy and nutrient requirements on the one hand, and the bioavailable energy and nutrient content of diets and food rations on the other. It appears difficult to deal with problems of energy and protein metabolism separately, and the suggestion was made that IDECG should become a Protein-Energy Consultancy Group.

We need to know more about energy and nutrient requirements during catch-up growth after infections. Our knowledge of functional correlates of anthropometric data is still very limited. What are the differences between wasting and stunting? Does stunting have important functional consequences? If so, how can it be prevented?

NCHS growth curves are useful as a reference, but policy makers often believe that all children have to grow along these curves. Under these circumstances, how do we deal with all the new information that breast- and bottle-fed infants differ in growth? Should the references be changed? To do so, we need more information regarding what growth can be considered optimal.

NCHS is working on a revision of their growth-reference data because the old references are no longer representative of the growth of U.S. children. Since NCHS references, however, are used internationally, should not new references be elaborated by an international team of scientists and based on all appropriate data currently available?

Decisions on optimal growth remain speculative as long as they are not related to functional outcomes. At present, we do not even seem to know whether breast- or bottle-feeding produces the better long-term outcome.