544 



tr. S. BUREAU OF FISHERIESJ 



23 are given data (from Tressler and Wells, 1924) concerning the 

 iodine content of various food materials, including fish. 



Table 23. — Iodine content of various foods 



Product 



Lettuce, leaf 



Oranges 



Lemons, whole. 



Wheat 



Milk... 



Butter 



Eggs 



Veal 



Beef 



Dried seaweed 



Clams 



Oysters 



Crabs, meat flakes. 



Lobster 



Shrimp 



Source 



fSignau , 

 \Bern... 



/Canada... 



\Australia- 



Bern 



Bulgaria 



Bern 



do 



Atlantic Ocean. 



.do. 

 .do- 

 .do. 

 .do. 



Iodine, 



parts 



per 



billion 



27 



6 



15 



106 



3 



19 



5 



106 



27 



22 



5 



900,000 



1,370 



1,160 



180 



1,380 



450 



Product 



Bluefish 



Cod 



Haddock 



Pollock 



Pompano 



Scup 



Spot... 



Spotted squeteague 



Squetcague (weakfish) _ 



Winter flounder 



Albacore, canned 



Salmon, canned 



Sardines, canned 



Cod, salted 



Mackerel, salted 



Herring, smoked 



Source 



Atlantic Ocean. 



do.... 



do-.. 



do 



do 



do 



do 



do 



do.-. 



do 



Pacific Ocean. . 

 do 



fCalifornia 



\Maine 



Atlantic Ocean. 



do 



do 



Iodine, 



parts 



billion 



2*50 

 240 

 290 

 120 



80 

 300 

 590 



20 

 230 

 180 

 320 

 250 

 430 

 570 



mo 



400 

 530 



Iodine is necessary for the proper functioning of the thyroid gland. 

 Deficiency of iodine is believed to be the cause of goiter and other 

 serious disorders. In inland regions, where natural land foods con- 

 tain little iodine, goiter is common. In Table 23 it will be seen that 

 the same food material from different sources may vary in iochiie 

 content, but fish as a group contain far more iodine than land foods. 

 For this reason fish, especially salt-water fish and shellfish, have been 

 proposed as a valuable preventive of thyroid disorders. 



HEAVY METALS 



It was pointed out above that copper and zinc may have some 

 function in the bod3^ Zinc is present in most of our foods, both meat 

 and vegetable. Both zinc and copper have been found in aU marine 

 mvcrtebrates that have been examined for them, except one species 

 of clam. Table 24 gives data (taken from Bodansky, 1920; Rose 

 and Bodansky, 1920; and Severy, 1922) concerning the prevalence 

 of these elements in Atlantic and Pacific coast marine animals. 

 (See also Willard (1908).) 



Table 24. — Copper and zinc in marine animals 



