HEALTH AND POPULATION 579 



ment. Nevertheless, the diet could in some respects be altered for 

 the better without much difficulty, as pointed out by many 

 writers, in particular Sir Daniel Hall (1936), who discusses the 

 food of Africans together with the related subjects of agriculture 

 and animal husbandry. In Nigeria groundnuts, which are widely 

 grown for export, would help to make good the protein deficiency 

 if developed as an article of consumption. Leguminous crops as 

 an addition to native diet are being tried in parts of the continent. 

 Soya beans, particularly, contain proteins of high nutritive value. 

 The lack of calcium could perhaps be reduced by a more extended 

 use of sweet potatoes, which are said to contain a higher propor- 

 tion of this element than other native foodstuffs in West Africa, 

 though this result is not confirmed in Kenya, where the lowest 

 limit of calcium for sweet potatoes was found to be lower than that 

 for European potatoes. 



Red palm oil, which is produced in large quantities in West 

 Africa, offers another opportunity for extended use as native food. 

 A recent study of this oil at Singapore by Rosedale and Oliveiro 

 (1934) shows that 'in addition to the ordinary energy-giving 

 quality of an oil, red palm oil is the only oil possessing vitamin A, 

 which could at the same time become available as food for the 

 population'. As a further point in its favour the vitamin content 

 of red palm oil appears to be less quickly activated into vitamin D 

 than that of coconut and other oils. Vitamin D is probably nearly 

 always sufficient in tropical diets, but too much of it works as a 

 calcium activator, which means that the usual deficiency of cal- 

 cium in native diets is increased by too rapid utilization. An 

 investigation on the value of palm oil in prison diets and of the 

 vitamin content of local oil is proceeding in Tanganyika. 



The problems involved in efforts to increase the consumption 

 of dried meat as a source of proteins have been discussed in 

 Chapters XIII and XIV. Again a fuller use of the continent's 

 fishery resources, both marine and freshwater, discussed in Chap- 

 ter IX, offers special opportunities for the improvement of diet, 

 since fish food provides not only protein, but calcium, iodine, etc., 

 in the most easily assimilated form. As a further source of animal 

 protein, insects are used as food in most parts of Africa: certain 

 stages in the life-history of termites are regarded as a luxury, a 



