10 THE ROLE OF ALGAE AND PLANKTON IN MEDICINE 



hibited growth dynamics of cartilage and bone caused by a suboptimal 

 intake of Vitamin A." 



The American brown kelps, Phaeophyta, studied extensively for their 

 vitamin content, were found rich in thiamin, niacin, and riboflavin. 

 Norris and others 66 found a thiamin concentration comparable to that of 

 many fruits and vegetables in Alaria valida, various Laminaria species, 

 Porphyra nereocystis, Rhodymenia pertusa, Viva lactuca, and especially 

 Porphyra perforata. The Vitamin B values of these algae were determined 

 in rats first fed on deficient basal diets for about two weeks, when weight 

 loss and cessation of growth took place. There appeared to be no loss in 

 Vitamin B activity from drying the algae, nor was there any noted rela- 

 tionship to the depth of the water from which the algae were harvested. 



Limu eleele and Limu lipoa, edible Hawaiian seaweeds, were found 

 by Miller 67 to be poor sources of both Vitamins B and C. Only small 

 amounts of Vitamin C were found in dulse {Rhodymenia palmata) . How- 

 ever, concentrations comparable to those in lemons have been reported 

 in both purple and green laver. Generally the spring and autumn har- 

 vests of seaweed are highest in ascorbic acid content. Unlike the case 

 with Vitamin B, seaweed collected from littoral zones is richer in Vitamin 

 C than that obtained from deeper waters. Although ascorbic acid is usually 

 destroyed by the drying preparatory to shipment of seaweed to market, 

 coastal populations still derive significant quantities of the vitamin from 

 eating the fresh algae. 68 * 69 



The occurrence in seaweed of the Vitamin D precursor, ergosterol, 

 has also been recognized. 70 Sauvageau reported marked anti-rachitic bene- 

 fits in 25 human subjects fed various macroscopic algae. 71 In 1952, 

 Ericson 56 reported the presence of Vitamin B 12 , folic acid, and folinic 

 acid in various brown and red seaweeds from the Baltic and North Seas. 

 The B 12 content of some of these was comparable to that in liver. The 

 presence of ^-tocopherol in seaweed was noted by Brown. 72 



Norris 66 would appear to have been correct when he wrote in 1937: 

 "Seaweeds contain no starch, and the complex carbohydrates which are 

 present are not readily hydrolyzed by the human digestive enzymes. The 

 value of [macroscopic] marine algae as food is due mainly to the in- 

 organic salts present and the vitamins." It is possible, however, that 

 broader chemical studies in the future may disclose more assimilable sub- 

 stances; and it is also conceivable that materials which in vitro presently 

 appear inutile may be shown to be otherwise in vivo. At any rate, the 

 nutritional compositions and values of the macroscopic algae are in strik- 



