FACTORS ALTERING CONCENTRATION OF CAROTENOIDS 487 



123 microgram per cent, while Yarbrough and Dann 837 reported values of 

 183 ± 18.4 microgram per cent and Caveness et a/. 838 cited an average 

 figure of 138 ± 62 microgram per cent. Hsu 839 gave 140 microgram per- 

 cent as an average for the blood carotene of thirty-three young healthy 

 Chinese adults. The results of Abels and co-workers 840 on sixty-two nor- 

 mal men and sixty-two normal women do not support those of Kimble, 833 

 who stated that women have a higher average value than men do. In 

 fact, Abels et al. S40 found higher values for men than for women, the averages 

 being 210 microgram per cent (range 40-500) and 180 microgram per cent 

 (range 80-400), respectively. Later, Harris, Hickman, Jensen, and 

 Spies 841 reported a mean of 210 ± 31 microgram per cent (range 80-370) 

 for seventy "normal" subjects. According to the arbitrary standards of 

 normality used in the Oxford Nutrition Survey as reported by Sinclair, 842 

 a value of 100 microgram per cent represents the lower limit of normal 

 blood, while a value below 50 microgram per cent indicates extreme ab- 

 normality. 



The plasma vitamin A values more or less coincide with those of caro- 

 tene. The range for the vitamin A in normal individuals is from 20 to 60 

 microgram per cent (67 to 200 I.U.). 843 Kimble 833 reported averages of 

 38 and 27 microgram per cent for men and women (127 and 91 I.U., re- 

 spectively). Other average figures are as follows: Murrill et a/., 834 27.9 

 microgram per cent (93 ± 15 I.U.) ; Sobotka, 835 18 to 24 microgram per 

 cent; Ralli and associates, 836 47.4 microgram per cent; Yarbrough and 

 Dann, 837 21.3 microgram per cent (71 ± 3.3 I.U.); Caveness et a/., 838 

 78.9 microgram per cent (263 ± 96 I.U.); Abels and co-workers, 840 51 

 microgram per cent (170 I.U. with a range of 132 to 208 I.U.) for men, and 

 44.7 microgram per cent (149 I.U. with a range of 103 to 195 I.U.) for 

 women; and Harris, Hickman, Jensen, and Spies, 841 61 ± 13 microgram 

 per cent (range 36 to 89 /jg.). Hsu 839 cites a figure of 16.8 Mg- (56 I.U. 

 with a range of 36 to 99 I.U.) for healthy young Chinese adults, while 

 Harris and Moore 844 recorded a value of 35.4 Mg. (118 I.U.) as the average 



837 M. E. Yarbrough and W. J. Dann, J. Nutrition, 22, 597-607 (1941). 



838 H. L. Caveness, G. H. Satterfield, and W. J. Dann, Arch. Ophthalmol, 25, 827-832 

 (1941). 



839 H.-C. Hsu, Chinese Med. J., 61, 238-243 (1943). 



840 J. C. Abels, A. T. Gorham, G. T. Pack, and C. P. Rhoads, J. Clin. Invest, 20, 749- 

 764(1941). 



841 P. L. Harris, K. C. D. Hickman, J. J,. Jensen, and T. D. Spies, Am. J. Pub. Health, 

 36, 155-160(1946). 



842 H. M. Sinclair, Vitamins and Hormones, 6, 101-162 (1948). 



843 One International Unit is equivalent to 0.3 fig. 



844 A. D. Harris and T. Moore, Brit. Med. J., 1947, 1, 553-559. 



