The state of nutrition of the people of this country is surveyed here on a broad scale and from a new angle. Instead of discussing minimum requirements, about which there has been so much controversy, this survey considers optimum requirements. Optimum requirements are based on the physiological ideal, which we define as “a state of well-being such that no improvement can be effected by a change in the diet.” The standard of adequacy of diet adopted is one which will maintain this standard of perfect nutrition.
The average diet of each of six groups into which the population has been divided according to income are compared with these requirements for perfect nutrition. The health of the population is reviewed to see to what extent inadequacy of diet is reflected in ill-health and poor physique.
It is difficult in the present state of knowledge to lay down precise and detailed criteria of perfect nutrition. The basis of comparison taken for health is, therefore, the state of health and physique of those groups of the population who can choose their diets freely, without any economic consideration seriously affecting their choice. For the purposes of this large scale survey individual errors of diet can be ignored. These errors are undoubtedly common. The diets, even of those who are able to purchase unlimited amounts of any foodstuff available, will improve as the knowledge of dietetics extends. Meantime, however, the state of nutrition of the higher income groups, whose diet is not limited by income, can be taken as a standard which can be attained with the present dietary habits of the people of this country.
The tentative conclusion reached, is that a diet completely adequate for health, according to modern standards, is reached at an income level above that of 50 per cent, of the population. This means that 50 per cent, of the population are living at a level of nutrition so high that, on the average, no improvement can be effected by increased consumption.
The important aspect of the survey, however, is the inadequacy of the diets of the lower income groups, and the markedly lower standard of health of the people, and especially of the children in these groups, compared with that of the higher income groups.
The method of grouping the population according to income is new and may be open to the criticism, among others, that it overemphasises the importance of children as an economic factor affecting standard of living. The basis of the grouping is the total family income divided by the number of persons, including children, supported by it. Thus an average income of 30s. per head per week is reached by a man earning £550 a year, with a wife, four children, and one domestic servant. It is also reached by a manual worker earning £3 a week with only a wife to support. The “higher income” and “lower income” groups cannot be simply identified with “rich” and “poor” in the generally accepted sense of these terms.
The lowest of the six income groups contains a disproportionately high number of children—rather more than a fifth of all the children in the country. This is the group whose diet falls furthest below the standard of adequacy for health. Great improvements in health have been and are being effected in these children by improved nutrition. The picture presented in the survey justifies all and more than all the efforts which have already been made, but opens up a prospect of still further improvement.
As is noted in the report, the data are too scanty to yield a picture fully accurate in detail. Moreover, both the technique of the investigation and the standard of dietary requirements adopted are new and must be regarded as still on trial. There is need for further investigation and further discussion of the whole question in all its complicated relationships, in order that the measures taken to deal with the situation may be based on generally accepted facts and well-informed public opinion.