742 
Fat-Soluble  Vitamin. 
{Am.  Jour.  Pharm. 
November,  19 19. 
SOME  PROPERTIES  OF  THE  FAT-SOLUBLE  VITAMIN 
(FAT-SOLUBLE  A).1 
The  day  has  passed  when  even  the  most  skeptical  critic  of  novel 
hypotheses  can  deny  that  certain  natural  fats,  notably  milk  fat,  egg- 
yolk  fat  and  various  tissue  oils,  exhibit  a  peculiar  potency  in  nutri- 
tion that  is  not  shared  by  many  other  wholesome  fats  which  enter 
into  the  dietary.  Whether  the  property  referred  to  be  designated 
as  a  vitamin,  a  food  accessory  substance,  a  food  hormone  or  auxi- 
mone  is  of  secondary  interest  so  long  as  its  chemical  nature  and 
mode  of  action  are  still  so  obscure.  The  fundamental  fact  that  has 
been  firmly  established:  When  a  suitable  source  of  the  fat-soluble 
vitamin  as  it  exists  either  in  animal  fats  or  in  green  plants  is  lacking 
in  the  diet,  nutritive  disaster  is  certain  to  follow  sooner  or  later, 
even  when  all  other  components  of  the  ration  are  ideally  adequate. 
We  are  here  dealing  with  some  as  yet  unidentified  food  factor  indis- 
pensable for  nutritive  well-being,  even  though  the  quantity  that  is 
required  may  be  measured  with  small  units. 
The  earlier  studies  of  the  fat-soluble  vitamin  were  largely  di- 
rected to  the  search  for  its  sources,  so  that  it  is  now  possible  to 
catalogue  a  considerable  list  of  foods  of  known  potency  with  respect 
to  the  factor  under  discussion.  The  practical  significance  of  this 
will  be  clearer  to  the  medical  practitioner  when  the  bearing  of  a 
deficiency  of  fat-soluble  vitamin  on  the  genesis  of  certain  symptoms 
of  malnutrition  is  further  elucidated.  A  shortage  of  the  vitamin  in 
the  human  dietary  has  already  been  convincingly  related  to  the  ap- 
pearance of  eye  disease  (xerophthalmia)  in  children;  and  English 
investigators  are  inclined  to  ascribe  rickets  to  a  similar  deficiency 
factor.  During  the  enforced  food  shortage  of  war-time  days,  the 
lack  of  butter,  eggs  and  meats  caused  considerable  concern  to  the 
food  authorities.  We  have  already  pointed  out  that  butter  substi- 
tutes which  are  made  from  beef  fats  or  oleo  oils  may  be  physiolog- 
ically comparable  to  some  extent  with  butter  in  their  growth-pro- 
moting power,  whereas  those  prepared  from  vegetable  oils  are 
inadequate  in  this  respect.2 
1  From  Jour.  Amer.  Med.  Assoc.,  Oct.  4,  1919. 
2  Osborne,  T.  B.,  and  Mendel,  L.  B. :  /.  Biol.  Chem.,  20:  379  (March), 
1915.  Drummond,  J.  G,  and  Halliburton,  W.  D. :  /.  Physiol,  51 :  235  (Sept.), 
1917.  Steenbock,  H.,  Kent,  H.  E.,  and  Boutwell,  P.  W. :  /.  Biol.  Chem.,  35 : 
517  (Sept.),  1918.  "A  Problem  Concerning  Edible  Fats,"  editorial  /.  A.  M. 
A.,  69:  1876  (Dec),  1917. 
