CAROTENOIDS 



An interesting report, which requires confirmation, is that high 

 altitudes reduce the carotene plasma levels ; a flight of 2 hr. at 500 

 metres caused a fall of 14 per cent, and a 1| hour flight at 4,000 metres 

 a 30 per cent. fall. ^ " ^ The drop in the carotenoid levels of the plasma 

 and milk of cows which occurs after massive doses of vitamin A {see p. 

 243) does not occur in humans. ^ ° ^ The plasma carotene levels of 

 humans with various pathological conditions are recorded in Table 42. 



Table 42 

 Carotenoid Conte7it of Blood of Normal and Pathological Human 



Cases 



236 



