Biological variations associated with change in lifestyle among the pastoral and nomadic tribes of East Africa

Abstract

The values of a number of anthropometric, cardiovascular and biochemical variables have been compared between tribal and non-tribal Samburu. Significant differences between the two groups were found for ponderal index, supra-iliac and mid-calf skinfold thicknesses, pulse rate and both systolic and diastolic blood pressures. Similar analyses were performed on samples from tribal and non-tribal Maasai; here significant differences were found for ponderal index, height, biceps skinfold thickness, pulse rate and systolic blood pressure. No significant differences were found in serum cholesterol or serum triglyceride for either the Samburu or the Maasai. Greater variability of the skinfold measurements was found in the non-tribal Samburu than in the tribal group; this effect was less marked in the Maasai. A principal component analysis and three discriminant function analyses were performed on the Samburu data. These analyses showed that the most marked difference between the tribal and non-tribal groups was in their blood pressure levels, the non-tribal sample having significantly higher mean values than the tribal members. Possible causes for the observed differences between tribal and non-tribal groups are discussed, and the findings are contrasted with those of an earlier study, in which significant differences in cholesterol but not in blood pressure were found between samples of rural and urban Maasai. This leads to the tentative hypothesis that blood pressure is affected immediately by the change in environment, whereas the effect on cholesterol levels is a longer-term one.

The Anatomy of Adipose Tissue in Captive Macaca Monkeys and Its Implications for Human Biology

“…Well-nourished, el derly humans are even fatter, with the 12 men dissected by Clarys et al [ 1984] averag ing 28.1 % and the 13 women 40.5 % adipose tissue. Nomadic tribesmen in East Africa have only 6-12% adipose tissue [Day et al, 1979], but the thinnest of the girl athletes examined by Katch and Spiak [1984] had 7 % by weight adipose tissue; 13 % was sug gested as the minimum necessary to support normal menstruation. Non-athletic female students aged 17-24 years were estimated to have 22-28% adipose tissue [Brown and Jones, 1977].…”

Accordance between V̇O2max and behavior in Ngisonyoka Turkana

“…There are indications from several studies Little et al, 1983;Day et al, 1979;Mann et al, 1965;Davies and Newson, 1975) that the nomadic Turkana display very low rates of cardiovascular disease, have low systolic and diastolic blood pressures compared with Western peoples and settled neighboring Africans, and are in general good health. Nevertheless, the fact remains that no means of monitoring exercising subjects (an EKG and/or cardiovascular specialist) was present during the testing.…”