Sensitivity analyses and meta-regression for hemoglobin suggested a higher response with lower trial quality ( suboptimal allocation concealment and blinding ) , use of condiments , and sodium iron edetate and a lower response when adults were included .
Consumption of iron-fortified foods results in an improvement in hemoglobin , serum ferritin , and iron nutriture and a reduced risk of remaining anemic and iron deficient
BACKGROUND The utility of iron fortification of food to improve iron deficiency , anemia , and biological outcomes is not proven unequivocally .
Iron-fortified bread. A long-term controlled therapeutic community-based experiment with ferrous sulphate-enriched flour.
The hematinic effect of ferrous sulphateenriched flour has been examined in a long-term , community-based experiment . During a period of 20 consecutive months 17000 metric tons of iron-fortified flour were produced at Tau M@lle in Stavanger , Norway ( total iron content 6.2 mg/100 g flour ) . There were neither complaints of rancidity of the flour nor of any harmful effect on its baking qualities . The monitoring of the effect of the iron-fortification programme was performed on an experimental group of 202 women of child-bearing age living in Stavanger . A control group of 215 women was established in Bergen .  Blood examinations ( Hb , Hct and MCHC ) were performed at the start of the experiment and repeated on three occasions during the study . The results failed to give conclusive evidence of the hematinic effect of the iron supplement . However , the results obtained in the few women with the lowest circulating Hlb levels ( Hb < 12 g/lOO ml ) suggested that the added iron was absorbed and utilized for Hb synthesis . The authors have recommended to the Norwegian health authorities that all white flour should be fortified with ferrous sulphate . I mt seems reasonable to apply the same level of enrichment as was recently proposed by the US Commissioner of Food and Drug Administration ( total level of iron 9 mg/ 100 g flour ) . Food fortification is a public health measure aim ed at improving and maintaining the health of individuals in the population through the provision of adequate levels of nutrient intake ( 13 ) . Iron is one of the nutrients which requires special consideration . Based on normal values for Hb concentration and other hematological parameters , we have in previous studies estimated the prevalence of anemia in various population groups ( 18 ) . Iron-deficiency anemia is rather prevalent in Norway : it is not uncommon in schoolchildren and is frequently found in women of reproductive age and in the elderly . At present the level of iron in the average Norwegian diet is only about 4 - 5 mg/l 000 kcal ( 28 , 29 ) . Infants and small children , elderly people , patients and physically inactive individuals with a low caloric intake , as well as those with an increased iron requirement due to growth , convalescence , menstrual bleeding , pregnancy and other special needs , are likely to receive an insufficient supply of iron . The recommended daily intake for women of reproductive age is , for example , 18 mg iron , which should be provided in no more than 1850 - 2 400 kcal ( 4 ) . Thus the lowcalorie consumer ( < 2 000 kcal/day ) requires a diet with no less than 10 mg iron/l 000 kcal in order to satisfy the iron needs . This is theoretically possible to accomplish by choosing foods with a high iron content ( blood , liver , kidneys , wholemeal bread , green vegetables ) . Apart from the fact that blood and entrails are in short supply , it is unrealistic to assume that the majority of people will change their food habits according to these suggestions . An increase in the dietary iron intake might be most easily accomplished through a fortification programme . Iron fortification of the Norwegian brown-cheese with ferrous sulphate was first performed on an experimental scale in the late 1960 's ( 26 ) . In 1972 the enriched cheese became available to the ordinary consumer . The most suitable vehicle , however , for iron fortification would probably be flour and bread . In Great Britain the Bread and Flour Regulations ( 1 ) require that either reduced iron or ferric ammonium citrate shall be added , if necessary , to restore the iron content of flour , other than wholemeal , to at least 1.65 mg/100 g flour . In Acta med . sc and . 194 464 H . Natvig and 0 . D. Vellar Denmark 3 mg iron/l00 g flour is added in the form of reduced iron to wheat and rye flour ( 12 ) . In Sweden iron enrichment of flour ( up to 7 mg iron/100 g flour as reduced iron , ferrous sulphate or ferrous fumarate ) is undertaken on a voluntary basis ( 14 ) . In the USA the level of iron in " enriched " flour is raised to that of wholemeal flour ( 3.5 mg Fe/100 g flour ) . However , the US Commissioner of the Food and Drug Administration has proposed an increase of the level of enrichment to ensure a level of 9 mg Fe/100 g flour ( 3 , 7 ) . Finch and Monsen ( 7 ) emphasize that such manipulation of the public diet carries with it the responsibility for monitoring its effect on the iron balance of the population and on the prevalence of iron deficiency and iron overload . Based on our previous Hb studies ( 18 ) we proposed that the possibility of iron enrichment of flour and bread should be considered also in Norway . I t would be necessary , however , to examine the biological effect of various iron preparations when baked into bread as well as the technological problems relating to the baking process . While iron fortification programmes have been in force for many years in many countries , there appear to have been few thorough attempts to evaluate their effectiveness until recently . Furthermore , the results of these studies have been controversial . Three long-term feeding trials with ferrous carbonate or ferrum-reductum-enriched bread ( 5 , 15 , 25 ) showed no effect on the Hb values . Studies reported by Stott ( 23 ) , however , are at variance with these negative results . Using prisoners , Stott fed ferrous-sulphate-enriched bread for four months and obtained a considerable increase in the Hb concentration . This work , however , has been justifiably criticized because there was no control group , and because the absorption of iron from the added ferrous sulphate would have to have been in excess of 30 % in order to account for the recorded Hb rise during the first two months of supplementation . During a long-term trial we fed ferrous-sulphate-enriched bread to 77 women inmates in a mental hospital ( 24 ) . A control group was given the same bread without fortification . After a 12week period the mean Hb level increased from 13.96 to 14.32 g/100 ml in the experimental group . This increase of 0.36 g/100 ml was statistically significant at the 5 % level . However , the Acta med . sc and . 194 mean Hb increase in the control group was almost as great , but these results were difficult to assess as so many of the controls dropped out . Thus the experiment did not provide convincing proof of the effectiveness of the supplement , In a recent long-term feeding trial by Elwood et al. ( 6 ) the effect of ferric-ammonium-citrateenriched bread was examined . Although the results were not entirely consistent , they indicated a small hematinic effect of the iron supplement . Balance studies ( 9 ) with bread enriched with ferrum reductum , ferrous sulphate of ferric orthophosphate revealed some absorption ( OR an average 3 % ) of the added iron . There was no particular difference in the amount of iron absorbed from the three preparations . In absorption studies ( 24 ) we have found that ferrous-sulphate-enriched bread gave favourable results , with an increase in serum iron values two hours after the test meal . When reduced iron was used for enrichment , the response was not so pronounced . It was also observed that the added ferrous sulphate was better absorbed from white wheaten bread than from wholemeal bread . In radioactive absorption studies Steinkamp et al. ( 22 ) examined the effect of bread enriched with radioactive ferrous sulphate , reduced iron , ferric orthophosphate , and sodium ferric pyrophosphate , and found an equal effectiveness of all four forms of iron used for enrichment . In recent studies Hoglund and Reizenstein ( 10 , ll ) , using more modern technique with a whole body counter , found that the absorption of iron from ferrous-sulphate-enriched bread was much higher than when reduced iron was used for enrichment . When fine grain-reduced iron was used to enrich flour , the absorption was 50 % lower , and when a coarser grain-reduced iron was used , it was 85 % lower , than when ferrous sulphate was used for enrichment . Animal studies performed by Fritz et al. ( 8 , 20 , 21 ) of the biological availability of iron in iron-depleted chicks and rats also indicated that ferrous sulphate has a high relative biological value compared with other iron compounds . I t was also found that ferrous sulphate added to a biscuit mix prior to baking was utilized nearly as well as the same quantity of ferrous sulphate added directly to the test diet ( 8) . When these animal repletion studies were compared with human plasma iron responses following test doses of Iron-fortified bread 465 five sources of iron ( ferrous sulphate , reduced iron , sodium iron pyrophosphate , ferric orthophosphate and ferrous carbonate ) a similar ranking with ferrous sulphate as the best compound was obtained in both experiments ( 21 ) . According to three comprehensive reports on the subject of iron fortification ( 2 , 13 , 16 ) most of the evidence suggests that ferrous sulphate is among the most effective forms . As a supplement to our previous absorption and utilization studies ( 24 ) we felt that a longterm controlled , large-scale community-based feeding trial with ferrous-sulphate-enriched flour and bread should be conducted . Ideally such a trial should evaluate the beneficial effect , if any , on representative sample s of the community in terms of a change in morbidity . However , indices of morbidity are relatively insensitive . Changes in Hb levels and other hematological data might be used , as an indirect measure of health , to assess the immediate effect of the fortification programme , The plan was to supply iron-fortified flour and bread to the entire population in one particular community and to compare the changes in certain hematological data of one group of this experimental area with those obtained in a control group from an area without fortification . MATERIAL AND METHODS Iron enrichment of flour Western Norway was chosen for the trial , as in a previous study we had observed somewhat lower Hb values in the western than in other regions of the country ( 17 ) . Furthermore , in the western region it was also possible , from a practical point
Sensitivity analyses and meta-regression for hemoglobin suggested a higher response with lower trial quality ( suboptimal allocation concealment and blinding ) , use of condiments , and sodium iron edetate and a lower response when adults were included .
Consumption of iron-fortified foods results in an improvement in hemoglobin , serum ferritin , and iron nutriture and a reduced risk of remaining anemic and iron deficient
BACKGROUND The utility of iron fortification of food to improve iron deficiency , anemia , and biological outcomes is not proven unequivocally .