492 



V. BLOOD LIPIDS 



teen females varying in age from sixty-nine to eighty-three years. Ac- 

 cording to the studies of Kirk and Chieffi, 867 there would appear to be a 

 definite decrease in carotene and vitamin A with advancing age. The 

 latter data are summarized in Table 17. 



Table 17 



Total Carotene, a- and /3-Carotenes and Vitamin A 



in Blood Plasma of Individuals of Various Ages" 



» Data adapted from E. Kirk and M. Chieffi, /. Nutrition, 36, 315-322 (1948). 



h Including the standard deviation. Figures in parentheses are the range of values. 



c Correction applied for total carotenes. 



d Correction applied for a- and /3-carotenes. 



(d) Plasma Carotene and Vitamin A as Influenced by Sex. Although 

 sex must play only a minor role in determining the normal levels of caro- 

 tene and vitamin A in the blood, there is some indication that it may have 

 importance. Getz and Koerner 868 reported sex differences in blood vitamin 

 A. According to the results of Kimble 833 and of Popper and Steigmann, 848 

 the blood carotene values are higher in women than in men, while the 

 plasma vitamin A in males exceeds the value in females. Moreover, in an 

 extensive experiment involving repeated tests on eighteen male and seven 

 female subjects, Week and Sevigne 129 demonstrated that the plasma vitamin 

 A levels were consistently lower for female than for male subjects, not only 

 during fasting but at all periods up to twenty-four hours after the ad- 

 ministration of 134,000 jug. of vitamin A. For a summary of these ex- 

 periments, see page 500. Additional data indicate variations in the sex 

 patterns. Thus, Szymanski and Longwell, 869 showed that, in infants and 

 young children, both plasma vitamin A and plasma carotene are higher 



887 E. Kirk and M. Chieffi, /. Nutrition, 36, 315-322 (1948). 



868 H. R. Getz and T. A. Koerner, Am. J. Med. Set., 202, 831-847 (1941). 



