198 li. M. Sinclair 



claim would not be made for aureomycin. Indeed we know 

 that it is possible for deficiency of vitamin B12 to arise in 

 strict vegetarians. The problem is not merely of academic 

 interest since very large areas of the world cannot be and 

 probably never will be supplied with sufficient animal protein 

 to meet optimum demands, and the question of supplementing 

 vegetable protein with amino-acids that are lacking or with 

 vitamin B^^ i^ ^^^ important one. Several trials have already 

 been carried out, in some of which animal protein was com- 

 pared with vegetable protein, in others supplements of 

 vitamin B12 were added to vegetable protein. None of these 

 trials is conclusive or satisfactory, usually because the test 

 has been of too short duration. In short trials, Widdowson 

 (1948) and also Gomez, Galvan, Bienvenu and Cravioto 

 Mufioz (1952) found no superiority of animal over vegetable 

 protein. For the past three years the Institute of Nutrition 

 of Central America and Panama has been studying the prob- 

 lem (Scrimshaw and Guzman, 1953; INCAP Annual Report, 

 1953): no effect of a supplement of animal protein was 

 found amongst children of El Salvador, apparently because 

 their diet was deficient also in other factors, but in Guatemala 

 the addition of vitamin B^^ (20 ij.g.) to children on a basic 

 diet of 6 g. of animal protein daily produced over a period of 

 eighteen months a highly significant increase in rate of gain 

 in height and weight. Others had previously claimed positive 

 effects with vitamin B^g (Wetzel, Fargo, Smith and Helikson, 

 1949; Wetzel, Hopwood, Kuechle and Grueninger, 1952; 

 O'Neil and Lombardo, 1951; Chow, 1951; Wilde, 1952; Spies, 

 Dreizen, Currie and Buehl, 1952), although negative reports 

 have also appeared (Downing, 1950; Rascoff, Dunewitz and 

 Norton, 1951; Benjamin and Pirre, 1952); none of these 

 tests was conclusive. Dean (1953) made a detailed study 

 on undernourished German children of the feeding of plant 

 ])roteins and considered that adequate substitutes for milk 

 could ])r()bably be ])rovided from plant sources; noting the 

 beneficial ellect of adding a small anioimt of milk, he suggested 

 that the addition of vitamin Bjg would be a highly important 



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