Adequate nutrition is required for survival and successful reproduction. However, there is great variety in human dietary patterns. The saying ‘Man ist was man iBt’ (man is what one eats) can be construed both to refer to the chemical composition of the body as the product of flows of nutrients and energy, and to the sociological sense in which dietary choice reflects the social persona of the individual. The science of nutrition has developed from chemistry and physiology and remains an essentially biological discipline. Social economic factors play an important role in influencing access to nutritional resources, but have tended to be seen as peripheral to the discipline.
The emergence of nutritional anthropology in the 1970s has tended to replicate the ‘two cultures’ of an anthropology divided methodologically and by theories into social and biological sciences. The former have been concerned with the social role of foodstuffs, the determinants of their production and distribution, and the management of short-ages. This has historically been a concern of social anthropology at least since the early work of †Audrey Richards (1939). For example, Freedman has defined nutritional anthropology as ‘the study of the interrelationship between diet and culture and their mutual influence upon one another’ (1976). In a practical context, this becomes the application of social anthropological data and methods to solving ‘the cultural aspects of human nutritional problems’, for instance where health programmes need to overcome what are seen as cultural barriers to improved nutrition (Freedman 1976). Jerome et al. (1980) adopt a similar approach which delineates the significance of four areas: dietary pattern; non-nutritional aspects of food related to ethnic identity, culinary tradition, social structure, social status and cultural change; cognitive aspects of food understood as part of ideological systems; and food as a vehicle of energy in studies of the human ecosystem.
By contrast, *biological anthropologists and nutritionists have treated food mainly as a vehicle of energy and nutrients. Nutritionists have focused on determinants of variation in nutritional status and its measurement, the nature of energy and nutrient requirements, ethnic differences in nutrient utilization, and the possibility of nutritional adaptation by biological and social means (Blaxter and Waterlow 1985; Ulijaszek and Strickland 1993). Biological anthropologists have tended to see nutrition as a dimension of the complex human-environment relationship. Thus, Haas and Pelletier (1989) and Haas and Harrison (1977) postulate several ways of approaching nutrition in human population biology: as a constraint or stressor; as a modifier of other environmental stresses; and as contributing to limits to human biological adaptation.
Nutrition as a constraint or stressor has been investigated in various ways. The focus can be on behavioural responses to the nutritional limitations set by staple foodstuffs. For example, an association between sago consumption and infanticide has been argued where this staple is a poor weaning food and long inter-birth intervals are desirable for successful child rearing. Seasonal nutritional stress can be managed by varying body weight and growth performance within limits, as well as by behavioural and social mechanisms, although the biological limits to this are unknown. The need to develop systems for predicting famines has given rise to models of household strategies for coping with shortages of varying severity and duration.
Nutrition as a modifier of other environmental stresses concerns its role in adaptation to climatic variation (Haas and Harrison 1977). Some protection against cold stress is afforded by insulative adipose tissue or muscle, and by an efficient, active thermogenic response. It is sometimes argued that this can also occur by the growth and development of a physique which reduces the ratio of surface area (potential heat loss) to body mass (heat source); and conversely, heat stress would favour a greater surface area to weight ratio. Some differences in physique between populations inhabiting cooler and warmer climates, or different climatic zones of the same region, have been attributed to this but the issue remains contentious. Climate can also influence nutrition through its effects on synthesis of vitamin D by the action of ultra-violet radiation on the skin. Where climate also promotes high-altitude living conditions, low oxygen tension (hypoxia) will interact with blood haemoglobin and iron nutriture to influence health.
The role of nutrition in defining limits to biological adaptation is significant in several ways (Haas and Harrison 1977). There is known to be variation across populations in the frequency of genetically determined enzyme and other polymorphisms. For example, this results in differences in the capacity to digest lactose (milk sugar), sucrose, and alcohol; and in the variable distribution of conditions such as coeliac disease, which depends on sensitivity to the wheat protein gluten. However, there is much that remains unknown about variants in nutrient utilization in different groups, and about the interactions between genes and nutrients which influence gene expression (Walcher and Kretchmer 1981). Relationships between nutritional deficiencies and behavioural disorders have been shown for iodine in regions of endemic cretinism in Asia, Melanesia, Europe and South America. However, protein-energy malnutrition during early childhood can also significantly influence later mental and motor development.
The concept of malnutrition rests on demonstrable impairment in physical, behavioural or psychological function. Without this criterion, the interpretation of nutritional data must remain unclear. The degree to which social values influence judgement of malnutrition is debatable. The lines of debate resemble those of arguments over the concept of health. A strictly biological definition would seem to allow the social context of malnutrition to be delineated separately, as for any disease; but the social and biological properties of disease may often seem to be confused (Lewis 1993).
The extent of human biological plasticity in nutritional requirements remains unknown. Studies of semi-starvation and individuals under-going prolonged total fasts suggest that absolute adaptive limits will vary with initial body size. However, the timescale over which adverse effects occur is likely to vary. Through their consequences for reproductive function, intra-uterine nutrition and post-natal growth performance, nutritional insults exert influences which often become apparent only across generations.
Population biology is not the only type of approach used in nutrition, a subject of which the interests range from the molecular to the international, and which uses a diversity of methods from atomic mass spectrometry to macro-economics. Closer to anthropology, factors influencing the distribution of food within *households will determine access to nutrients and energy for many dependants. Studies of those factors which govern patterns of food distribution have helped in the understanding of sex-related patterns of under-nutrition and early mortality in the Asian subcontinent (Wheeler 1988; Harriss 1990). The relationship of these patterns to systems of *kinship and †inheritance, and to social ideas of responsibility, right and obligation is an area which would repay future careful inter-disciplinary investigation.
Blaxter, K.L. and J.C.Waterlow (eds) (1985) Nutritional Adaptation in Man, London: John Libbey
Freedman, R.L. (1976) ‘Nutritional Anthropology in Action: An Overview’, in T.K.Fitzgerald (ed.) Nutrition and Anthropology in Action, Amsterdam: Van Gorcum
Haas, J.D., and G.G.Harrison (1977) ‘Nutritional Anthropology and Biological Adaptation’, Annual Reviews in Anthropology 6:69–101
Haas, J.D. and D.L.Pelletier (1989) ‘Nutrition and Human Population Biology’, in M.A.Little and J.D.Haas (eds) Human Population Biology: A Transdisciplinary Science, Oxford: Oxford University Press
Harriss, B. (1990) ‘Food Distribution, Death and Disease in South Asia’, in G.A.Harrison and J.C.Waterlow (eds) Diet and Disease, Cambridge: Cambridge University Press
Jerome, N.W., R.F.Kandel and G.H.Pelto (eds) (1980) Nutritional Anthropology: Contemporary Approaches to Diet and Culture, New York: Redgrave Publishing Co.
Lewis, G.A. (1993) ‘Some Studies of Social Causes of and Cultural Responses to Disease’, in C.G.N. Mascie-Taylor (ed.) The Anthropology of Disease, Oxford: Oxford University Press
Richards, A.I. (1939) Land, Labour and Diet in Northern Rhodesia, Oxford: Oxford University Press
Rivers, J.P.W. (1988) ‘The Nutritional Biology of Famine’, in G.A.Harrison (ed.) Famine, Oxford: Oxford University Press
Ulijaszek, S.J. and S.S.Strickland (1993) Nutritional Anthropology: Prospects and Perspectives, London: SmithGordon & Co.
Walcher, D.N. and N.Kretchmer (eds) (1981) Food, Nutrition and Evolution, New York: Masson
Wheeler, E.F. (1988) Intra-household Food Allocation: A Review of Evidence, London: Department of Human Nutrition, London School of Hygiene and Tropical Medicine, Occasional Paper 12
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