Dr E. M. DeMaeyer
We are pleased to welcome the members of this Expert Committee in Rome. We hope that the deliberations of the Committee will be fruitful and that the report will be so exhaustive and so perfect that nobody will feel the need to improve on it for many years to come.
It is remarkable to note how long the report on calorie requirements has stood the test of time. Seven years ago, a consultant concluded that the second report published in 1957 was still valid. When one reads it, one is struck by the care and the apparent precision with which calorie requirements of population groups can supposedly be calculated. In practice, however, one soon realizes that this precision is illusory because of the difficulty of evaluating the single most important factor influencing requirements, i.e., the physical activity. Energy expenditure is related to the intensity of muscular work and the latter to the type of employment. The relationship between energy expenditure and employment is, however, a relatively loose one because of differences in the environmental conditions of work, the adaptation of tools, and the rules or habits of work. The level of development of a society influences to a considerable extent the physical expenditure of energy. The development of public transportation and the more or less generalized ownership of private means of transportation in most developed countries have changed considerably the conditions of life and consequently the level of physical activity.
While the determination of the energy expenditure involved in a constant physical activity is relatively easy, the calculation of the same expenditure on a 24-hour basis is quite difficult, in view of the near impossibility of recording every gesture of a man for that period of time. One must make a number of assumptions and though these may be relatively correct in a given environment, it is almost sure that the results cannot be extrapolated to people living in different circumstances. The problem raised here is a difficult one, and it may be that in the future the collaboration of specialists on conditions of work, perhaps from the ILO, would be useful in order to clarify this section of the report.
Two Expert Committees have reviewed the question of recommended intakes of proteins. The second one has come forward with new concepts which have raised some interesting questions: it does not seem, however, that from a practical point of view they have been as useful as hoped for. For the determination of minimum protein requirements, a factorial approach was used in the second Committee's report. It has been suggested by some that the same method should be used in this Committee's report and that lower figures should be assumed for endogenous nitrogen losses, thereby decreasing the estimates of minimum protein requirements. There is some evidence that it may be possible to keep adults alive on these smaller quantities of protein, but unfortunately some of the experiments have been marred by technical difficulties. One would like to see more experiments of this type conducted in order to ascertain the long-term adequacy of the amounts of proteins thus proposed. On the other hand, in some countries there is a trend to revert to figures for recommended intakes of protein based on actual dietary consumption figures or on percentages of calories supplied by protein, which in developed countries range around 12. These methods lead to the acceptance of higher figures for recommended intakes of protein: the fact that there is some historical evidence that these intakes are adequate may tempt some to accept them as the best figures available. When the Committee reviews the problem it should remember that it cannot be taken out of context and that the general principles underlying this report should be as far as possible similar to those used by other committees when dealing with recommended intakes of other nutrients. In this connexion, it may very well be that the whole philosophy of the FAO/WHO Expert Committees on Requirements and Recommended Intakes of Nutrients should be re-examined as soon as possible in the light of past experience so that common principles can be defined for the establishment of the recommendations. So far, there has always been some ambiguity as to whether the international figures for recommended intakes should constitute ideal objectives or should be practical enough to enable each government to implement them without setting impossible goals. The successive committees that have reviewed the recommended intakes of various nutrients have so far been unable to come up with a completely satisfactory answer to this question and their attitude has varied according to each nutrient. I would suggest therefore that before the Committee starts reviewing the problem of energy and protein requirements, it might spend some time reviewing the general principles that should guide it during the discussion of recommended intakes.
Finally, I should like to indicate that for the first time the interrelationship between energy and protein requirements will be discussed. This is obviously an important problem, especially in view of the recent deliberations of the 8th Expert Committee on Nutrition on the dietary factors involved in the causation of proteincalorie malnutrition.
It only remains for me to wish every participant an interesting meeting: this I do with great pleasure. meeting: this I do with great pleasure.