MAMMALIAN CAROTENOIDS 



by Chanda et al. ^ ^ in Scotland. Lescher et al. ^ ^ in their wide survey 

 of the vitamin content of human breast milk found that the colostral 

 carotenoid levels diminished rapidly from the first day of lactation 

 to the 5th or 6th day w^hen they w^ere stabilized at levels w^hich v^ere 

 maintained for as long as lactation lasted (up to 300 days in some of the 

 cases investigated). They found that the average carotenoid con- 

 centration of 1st day colostrum was 241 (ig./lOO ml. and the mean 

 maintenance level about 25 [ig./lOO ml. Kon and Mawson, 2' stating 

 their results with respect to fat, recorded concentrations of 2mg./100g. 

 at the 3rd-4th day of lactation ; this quickly fell to a maintenance 

 level of 0-36 mg./lOO g. {See Tables 42 and 44 for further values.) 



In the same way as cows milk, human milk shows seasonal variations 

 according to the availability of green food. ^ 2, e ? 



Milks rich in fat have a high concentration of carotenoids, whilst 

 those poor in fat, although the total amount present was low also, have a 

 high carotenoid concentration. The concentration in the milk of p- 

 carotene is always lower than in the blood, whilst that of the other 

 carotenoids was higher. The lower ^-carotene values may be due to 

 (a) its conversion into vitamin A in the mammary gland or {h) the 

 mammary gland acting as a partial barrier. The transfer of breast milk 

 to infants must be efficient for there are reports of sucklings with 

 carotenaemia. « «, e 9 



(ii) Pathological Aspects 



Excessive carotenoid intake can lead to intense yellow pigmentation 

 of the skin owing to deposition of carotenoids in the hypodermis. 

 This pseudo-icterus or xanthemia is always accompanied by caro- 

 tenaemia and, according to van den Bergh, Hymans and Snapper, "> 

 a carotenuria ; however, recent exhaustive investigations by Lawrie, 

 Moore and Rajagopol'^ indicate that the appearance of carotene in 

 the urine is highly improbable under any conditions. The condition of 

 carotenaemia is apparently without ill-effect and disappears on removing 

 carotenoids from the diet, ' ^^ ' ^ similarly the withdrawal of carotenoids 

 from the diets of normal humans quickly reduces the blood levels to 

 zero. There is one very interesting report of a case in which caroten- 

 aemia was due to the failure of the patient to convert carotene into 

 vitamin A in the intestine. The carotene which thus escaped trans- 

 formation passed into the blood in such quantities that the carotene : 

 xanthophyll ratio was reversed. ' ^ 



The pigmentation of the skin in diabetics, " xanthosis diabetica," is 

 also due to subcutaneous accumulation of carotenoids. This is generally 

 accompanied by a carotenaemia and has led to the conclusion that the 



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