The Availability of the Iron in Hawaiian-Grown Vegetables

The availability of iron in certain grass, clover and herb species. I. Perennial ryegrass, cocksfoot and timothy

“…The rate of haemoglobin regeneration is then taken as an indication of the relative effectiveness of that particular dietary source of iron as compared with the regeneration when a solution of an iron salt is fed. This method has also been used with success by several other workers (Kletzien, 1938;Underwood, 1938;Lucas & Summerfeldt, 1939;Harris, Mosher & Bunker, 1939;Freeman & Burrill, 1945;Miller & Louis, 1945) and has several advantages over the previously mentioned methods. As the rats are only about 6 weeks old at the beginning of the experimental period, and in a highly anaemic condition, they will require iron both for recovery and for the production of the additional haemoglobin occasioned by increases in body weight.…”

“…Such iron, it was claimed, was available to the animal and could be estimated by means of the reagent aa'-dipyridyl. While several investigators (Elvehjem et al 1933;Sherman et al 1934a, 6;Smith & Otis, 1937a;Harris et al 1939;Widdowson & McCance, 1944) have claimed that the method gives good agreement with results obtained by means of a bioassay, there is an equally strong body of opinion (Myers, Remp & Bing, 1935;Ascham et al 1938;Hahn & Whipple, 1938;Miller & Louis, 1945) that results obtained by this method show very poor agreement with those obtained by means of a bioassay. As availability denned in this way has little physiological significance, the procedure has accordingly fallen into disrepute.…”

Mineral availability and techniques for its measurement

“…However, few such methods have been reported, and even these do not find general acceptance. T h e determination of 'available' iron by means of the dipyridyl reagent which reacts with ionic ferrous iron has been shown to be unsound (Miller & Louis, 1945). Anderson, Cheng & Burroughs (1956) have devised a rapid in vitro method of evaluating phosphorus supplements for ruminants by measuring the decomposition of cellulose in an artificial rumen when the supplements were the sole source of phosphorus for the micro-organisms.…”

Utilization of Food Iron – An Epidemiologist’s View

“…The remainder is in the form of complexes, the absorptive mechanism of which is not understood but which may vary for different foods, some of which, like haem iron may be absorbed directly [17,106] and it has recently been suggested that this fraction may not be as effi ciently utilized for haemoglobin synthesis as the ionizable portion of the total food iron [16]. The relative availabilities of iron in a wide variety of foodstuffs have been estimated from the rate of haemo globin synthesis in anaemic animals [40,71,83,88,96,101], from long term iron balance studies in animals or in man [8,47,55,68,115], and from studies of the retention, or absorption of radio-active iron either given with food [14,15,18,23,81,97], or biologically incorporated into a foodstuff [6,17,18,22,48,75,91,104,111]. The value of many of these studies to problems of iron balance in man is limited as they were conducted on animals or methods which are unrealistic because of assumptions required for their interpretation or because a very large dose of iron was used [99,74].…”