Studies in diet, nutrition, and fertility among a group of Kalahari Bushmen in Botswana

To clarify the nature of the existence of the Kalahari Bushmen in Botswana it is necessary to build on the foundation that has been laid in forager studies by turning to controlled systematically collected data. The effort made has been directed to this purpose. A guiding point of departure in this research has been Walkers admonition in 1958 that the greatest need is to elucidate the relations among patterns of diet consumed of metabolism imposed and of physiology occurring in a social context. A fundamental proposition underlying the work is that physique and physiology their realization and maintenance are in significant part functions of situational contexts and they are subject to considerably flux. Thus the motivation of the research has been to investigate ongoing processes on a long-term basis rather than to describe isolated events. The research plan combines well-established methods of ethnography with some developed recently by field naturalists. Specifically the following statements are addressed: 1) body size of sample group varies in relationship to quantitative and qualitative fluctuations in food availability; 2) body composition varies in relation to dietary quality; 3) fertility in the sample groups varies in relation to body composition; and 4) social factors by differentiating access to both wild and domestic food products affect body composition and hence fertility. There are no locations in Botswana or elsewhere that are free of outside influence on forager traditions but /ai/ai is among those locations least overwhelmed by other Africans and European influence was until 1976 less pervasive than in most of Botswana. The Bushmen at /ai/ai call themselves zu/oasi and this term is used when referring to /ai/ai people. Bushmen is used when referring to the foraging click-language peoples of southern Africa. Field work was carried out in 3 periods: August 1973-January 1974; January 1975-June 1976; and May 1979-August 1980. The average number of zu/oasi in residence at /ai/ai during the study periods was about 160; there were also about 35 Herero. All of the data presented--lower weight in seasons of dietary stress along with lowered cholesterol and in some subjects raised triacylglycerosis are consistent with data reported by Truswell and Hansen (1976) and Bronte-Steward et al. (1960) which show seasonally lowered serum albumin and variable subscapular skinfold thickness. These point to fluctuations in nutritional status as a regular part of zu/oasi life. Losses of serum albumin are accompanied by proportional gains in extra-cellular water and it is possible that part of the weight and skinfold thickness observed in seasons of stress are because of edema. Births to zu/oasi women tend to cluster in association with these variations in biochemistry but at this time causal relationships among investigated variables cannot be documented.