Lead Review Article December 2002: 391–406 TheUsefulness of Elemental Iron for Cereal Flour Forti cation: ASUSTAIN TaskForce Report RichardHurrell, Ph.D.,Thomas Bothwell, M.D., James D. Cook,M.D., Omar Dary,Ph.D., Lena Davidsson,Dr. Med.Sc., Susan Fairweather-Tait, Ph.D.,Leif Hallberg,M.D., SeanLynch, M.D., Jorge Rosado, Ph.D., Tomas Walter, M.D., and Paul Whittaker,Ph.D. Fortication of cereal ours may bea useful public Introduction health strategy to combat iron deciency. Cereal Ironde ciency is a majorpublic health problem in ours that areused shortly after production (e.g., baking our)can be forti ed with soluble iron com- developingcountries that affects up to 50% of infants, pounds,such as ferrous sulfate, whereasthe ma- children,and women of childbearingage in poorer pop- jority of ours stored for longer periodsis usually ulationsof Africa, Asia,and Latin America. Approxi- fortied with elemental iron powdersto avoid un- matelyone-half of these people suffers from themost acceptablesensory changes. Elemental iron pow- severeform ofiron de ciency, iron de ciency anemia dersare less well absorbedthan soluble iron com- (IDA). IDA isanimportantcause of cognitivede cits in poundsand they vary widely in their absorption infantsand young children; 1 itcan cause premature dependingon manufacturing method andphysico- birth2 andincreased maternal 3 andperinatal mortality. 4 chemical characteristics. Costs vary with powder IDA alsohas a profoundeffect on workperformance and type, but elemental iron powdersare generally less productivity. 5,6 Ithas important negative economic con- expensive than ferrous sulfate. This review evalu- sequencesin countries where it is a majorhealth prob- ates the usefulness of the different elemental iron lem.7 For healthand economic reasons, therefore, many powdersbased on results from in vitro studies, rat developingcountries are evaluating strategies to combat assays, human bioavailability studies, andef cacy ironde ciency. Whereas food forti cation is usually studies monitoring iron status in human subjects. It consideredthe most cost-effective long-term approach to concludes that, at the presenttime, only electrolytic combatnutrient de ciencies, 8 itshould form partof a iron powdercan be recommended as aniron forti- multiple-strategyapproach that includes iron supplemen- cant. Becauseit is only approximately half as well tationand dietary modi cation. Forti cation of wheat absorbedas ferrous sulfate, it should beadded to ourwith iron and vitamins has been used in theUnited providedouble the amount of iron. Statesand some European countries for morethan 50 Key Words: elemental iron, iron bioavailability, years.Although wheat ourforti cation was suggested cerealforti cation, wheat our fortication asthe main reason for theimproved iron status of ©2002International Life Sciences Institute Swedishwomen, 9 itsef cacy has never been properly evaluated10 andits usefulness has been questioned. To understandthe issues that underlie the current debate, it Drs. Hurrell and Davidsson are with the Swiss Fed- ishelpful to consider the factors that in uence the bio- eral Institute of Technology, Zu¨rich, Switzerland. Dr. availabilityof forti cation iron. CORE Bothwell is withMetadata, citation the and similar papers University at core.ac.uk of Witwatersrand, Johan- Provided by RERO DOC Digital Library nesburg, SouthAfrica. Dr.Cook is with the Kansas University Medical Center, Kansas City, Kansas, USA. Factors Affecting theBioavailability of Dr.Dary is with MOST,the Micronutrient USAIDPro- Fortication Iron gram,Arlington, VA, USA.Dr. Fairweather-Tait is with the Institute of FoodResearch, Norwich, UK.Dr. Hallberg is Theamount of fortication iron absorbed from apartic- with the University of Go¨teborg,Go ¨teborg,Sweden. Dr. ulardiet depends on three factors. These include the Lynch is with the Eastern Virginia Medical School,Nor- compositionof the diet, the iron status of individuals folk, Virginia, USA.Dr. Rosado is with the Institute of consumingthe diet, and the relative bioavailability of the Medical Sciences and Nutrition, MexicoCity, Mexico. 11 Dr.Walter is with the Institute of Nutrition and Food ironforti cant. Thereare twotypes of iron in the diet, Technology, Santiago,Chile. Dr.Whittaker is with the US hemeiron (derived from hemoglobinand myoglobin) Foodand DrugAdministration, Washington DC,USA. andnonheme iron (derived mainly from cereals,vegeta- NutritionReviews ,Vol. 60,No. 12 391 bles,and fruit). Most forms ofnonhemeiron in a meal, CurrentUse of IronForti cants whateverthe origin, enter a commonpool during diges- In1941, the United States was the rst countryto enrich tionand are thus equally susceptible to a numberof low-extractionwheat ourwith iron and vitamins; by promotersand inhibitors of ironabsorption. 12 The major 1965,virtually all white wheat ourand wheat bread promotersof iron absorption are meat and ascorbic andmost corn meal (86 –94%),grits, and macaroni acid,12 whereasthe major inhibitors are phytates and 13 productswere forti edwith iron, as were alargepro- polyphenols. 17 portionof other cereal products. By1979, most of Solubleiron forti cants,such as ferrous sulfate, theready-to-eat breakfast cereals (92%) were alsoforti- enterthe common pool of nonhemeiron completely and edwith iron (together with a selectionof vitamins) areabsorbed to the same degree as isintrinsic nonheme toprovide some 25% of the Recommended Daily Al- ironin the diet. This iron is well absorbed when the lowancesper serving. 18 Andas commercial cereal – dietcontains adequate amounts of ascorbic acid and/ or basedweaning foods became popular, they were forti ed meat,but it is poorly absorbed from dietsin which withiron because infants are highly susceptible to iron 14 inhibitorsof iron absorption predominate. Ferrous de ciency.19,20 sulfateand other soluble iron complexes can only be Mandatoryenrichment of white wheat our with usedwhen the forti edcereal is consumed shortly ironwas introducedin the United Kingdom and Canada afterproduction; this is because they are chemically in1953 and many other countries have since introduced reactiveand tend to produce undesirable organoleptic eithermandatory or voluntary enrichment, usually add- changeswith time in the vehicles to which they are ing suf cientiron to whitewheat ourtorestorethe level 10,15,16 added. tothat in whole grain or 80%-extraction our (U.K.). Whencereal products will be stored for longer Countriesthat require iron to be added to wheat our periods,forti cantsthat are less soluble in the upper includeChile (30 ppm), Guyana, Kenya, and Zambia (all gastrointestinaltract are frequently used. Although such 29–36ppm), Nigeria (35 ppm), United Kingdom (16.5 inertcompounds do not cause organoleptic changes ppm),United States (44 ppm), 21 Mexico(24 ppm), whenstored in a varietyof vehicles,they tend to be less andvarious Central American countries including wellabsorbed because they are less soluble in gastric ElSalvador, Costa Rica, Guatemala, Honduras, Nica- juice.Once dissolved, their absorption, like all iron ragua,and Panama. In Germany, Holland, Belgium, presentin thecommon pool, is dependenton theenhanc- Spain,and Switzerland, iron forti cationof wheat our ers andinhibitors of ironabsorption present in the meal isvoluntary. andon theiron status of the consumer. The most widely Becauseof its high nutritional bioavailability and usedof these compounds, particularly in cerealproducts, low cost, nedried ferrous sulfate is often the best iron iselemental iron. Elemental iron is relatively inexpen- sourcefor forti cation.It can be used in bakery our siveand does not cause adverse avorand color changes (whichis typically used within a monthafter milling), thatoften occur with prolonged storage of soluble iron insemolina, and in other types of low-moisture compounds.Wheat and maize oursare selected as wheatproducts such as noodles, macaroni, and spaghetti. forti cationvehicles because these foods are usually Morewidespread use of ferrous sulfate is limited by centrallyprocessed and regularly consumed in suf cient thefact that it often causes rancidity in stored cereal quantitiesby at-risk population groups. There are, how- oursand unwanted color changes in some cereal ever,certain unanswered questions relating to the use of products.16,22 Analternative to ferrous sulfate is fer- elementaliron because it isnot a singleentity but rather rousfumarate, which, although more expensive and existsin various forms dependingon the manufacturing insolublein water, has a bioavailabilitysimilar to ferrous process. sulfate.It therefore causes fewer organolepticproblems Threedistinct families of elemental iron powders andsome European manufacturers use it tofortifyinfant havebeen used: iron reduced by hydrogen or carbon cereals.10 monoxide,electrolytic iron, and carbonyl iron. Each Elementaliron powders are, by far, themost widely manufacturingprocess produces a powderwith a distinct used forti cantsfor wheat ourand other cereal prod- particlesize distribution, density, surface area, chemis- ucts,including breakfast and infant cereals. 23,24 Whereas try,and shape, all of which can affect iron bioavailabil- elementaliron powders are the most widely used iron ity.The unique qualities of the various powders have forti cants,many researchers have investigated whether largelybeen overlooked owing to the food industry ’s they are suf cientlywell absorbed from cerealproducts frequentuse of the generic name “reducediron. ” It is tobe nutritionally useful. 24–28