ANEURINE (thiamine) 



^-Aminobenzoic acid 

 Biotin 

 Folic acid 

 Pantothenic acid 

 Pyridoxine 

 Nicotinic acid 

 Aneurine 

 Riboflavine 



Excretion a 

 Per Cent. 

 Intake 

 {Mean) 

 230 

 378 

 542 

 112 



57 

 31 

 57 

 91 



Urinary and 



Intake Faecal Excretion 



97-220 (188) 331-398 (373) 



37-54 (44) 136-236 (163) 



43-86 (62) 226-397 (310) 



4-I9-5-30 (473) 4-07-6-72 (5-25) 



i*32-2-46 (1-76) 0-94-I-07 (i-oi) 



I2-4-20-9 (15-6) 3-32-6-64 (4-82) 



I-24-I-63 (1-44) 0-36-I-02 (078) 



I-74-I-98 (1-84) I74-I-98 (1-84) 



A similar series of tests was carried out on five young men main- 

 tained on a diet containing limited amounts of all the members of the 

 vitamin B complex. Two other men were given the same diet supple- 

 mented with amounts of each vitamin equal to or greater than the 

 amounts contained in the normal diet previously given. With the 

 restricted vitamin intake, the faecal excretion of aneurine and of the 

 other vitamins was at least as high as that on the normal diet, and 

 was unaffected by vitamin supplementation. The faecal excretion of 

 aneurine actually exceeded the dietary intake. The urinary excretion 

 of aneurine, on the other hand, and of riboflavine, N^-methylnicotin- 

 amide and pantothenic acid decreased markedly on the restricted 

 diet, but returned to normal on supplementation. With the other 

 vitamins the urinary excretion was affected to a smaller extent. 



It is evident from these results that all the B vitamins are syn- 

 thesised by the intestinal flora, but that the requirements of aneurine, 

 riboflavine and nicotinic acid as reflected in the urinary excretion must 

 be met from the vitamins supplied in the diet. Possibly with the 

 other vitamins absorption takes place to a sufficient extent to prevent 

 the development of deficiency sjrmptoms. This may be the reason 

 why deficiencies of ^-aminobenzoic acid, folic acid, biotin, pantothenic 

 acid and, probably, pyridoxine are virtually unknown except in ex- 

 perimental subjects. Only with aneurine, riboflavine and nicotinic 

 acid are characteristic deficiency symptoms produced when the diet 

 contains inadequate amounts. It must be presumed that although 

 bacterial synthesis of these three vitamins may occur in the intestine 

 they are not normally absorbed, although sometimes, as in Najjar's 

 experiment, animals may be able to make use of the aneurine, ribo- 

 flavine or nicotinic acid produced by bacterial action. That no 

 absorption of bacterial aneurine normally occurs was the conclusion 

 reached by B. Alexander and G. Landwehr,^^ for neither aneurine nor 

 cocarboxylase was absorbed from the large intestine when administered 

 by retention enema. This is a complete contradiction of the result 

 obtained by Najjar and Holt. 



78 



