Maternal Body Mass Index, Dietary Intake and Socioeconomic Status: Differential Effects on Breast Milk Zinc, Copper and Iron Content

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1 P P P Helth Promotion Perspetives, Vol. 1, No., 011; P: ORIGINAL ARTICLE Open Aess Mternl Body Mss Index, Dietry Intke nd Soioeonomi Sttus: Differentil Effets on Brest Milk Zin, Copper nd Iron Content P, Seyed Jml Gyem- 1 Leil NiknizP P, *Rez MhdviP P, Bhrm Pourghssem GrgriP 3 1 mgmip P, Zein NiknizP 1 3 PStudent Reserh Committee, Shool of Puli Helth & Nutrition, Triz University of Medil Sienes, Triz-Irn PTriz Peditri Helth Reserh Center, Shool of Puli Helth & Nutrition, Triz University of Medil Sienes, Triz-Irn 3 PNutrition Reserh Center, Shool of Puli Helth & Nutrition, Triz University of Medil Sienes, Triz-Irn ABSTRACT (Reeived: 04 July/ Aepted: 17 De 011) Bkground: As rest milk mironutrients ontent re essentil for helth nd growth of the infnts, this study ws onduted to determine the rest milk zin, opper nd iron onentrtions nd their possile orreltions with mternl nutritionl sttus, dietry intkes s well s soioeonomi sttus. Methods: Brest milk smples nd informtion on mternl nthropometri hrteristis nd dietry intke were olleted from 90 Irnin ltting women with 3 different soioeonomi sttus who exlusively restfed their infnts. Conentrtions of tre elements were nlyzed using tomi sorption spetrophotometry. Nutritionist III progrm, Multiple Regression nd ANOVA test were used for dt nlyses. Results: The men milk zin, opper, nd iron onentrtions were 1.93 ± 0.71, 0.58 ± 0.3, nd 0.81 ± 0. mg/l, respetively. In ll three SES groups only zin men level ws lower thn the reommended rnge. A signifint differene ws oserved in rest milk zin, opper nd iron onentrtion etween high nd low SES groups (Zn (P<0.001), Cu (P<0.001) nd Fe (P<0.044)) nd lso moderte nd low SES groups (Zn (P<0.03), Cu (P<0.001) nd Fe (P<0.049)). After djusting for mternl ody mss index (BMI), soioeonomi sttus, men dietry energy, zin, opper, nd iron intkes, there ws negtive nd signifint ssoition etween mternl ge nd rest milk zin (=-0.8, P<0.034), opper (=-0.18, P<0.048), nd iron (=-0., P<0.04) onentrtions. Conlusion: In low soioeonomi group with lower men ge, rest milk minerl levels were higher thn others nd there ws no signifint orreltion etween minerl levels nd dietry intke. Hene it is supposed tht mternl ge my e etter preditor of rest milk minerl levels. Keywords: Brest Milk, Zin, Copper, Iron, Infnts growth, Soioeonomi groups Introdution The World Helth Assemly reommends the exlusive restfeeding of infnts until 6 months of ge [1]. Humn milk is omplex mixture of mronu- *Corresponding Author: Dr Rez Mhdvi. Tel: E-mil: mhdvirez@hotmil.om 140

2 Nikniz et l.: Mternl Body Mss Index trients nd mironutrients tht should provide the infnt with nutritionlly omplete food []. Minerls re essentil mironutrients for growth nd development of helthy tissues [3], nd it hs een suggested tht tre element defiienies n led to impired growth during infny nd hildhood [4]. Iron (Fe) nd zin (Zn) defiieny re puli helth onerns during infny, espeilly in developing ountries [5]. Humn milk tre element ontent differs from region to region [3] nd it proly would e ffeted y soioeonomi sttus (SES) [4]. The Hondurn mothers elonging to low soioeonomi sttus hd signifintly higher rest milk zin nd opper onentrtions [6]. However in Indi, the zin nd opper (Cu) onentrtions in milk of women from the low-inome group were lower thn tht of the high-inome group [4]. The influene of mternl diet nd nutritionl sttus on the qulity nd quntity of their milk is frequent topi of disussion [7, 8]. Studies on humns out the effet of mternl diet on the onentrtions of iron, zin, nd opper in rest milk hve shown the mixed results [6, 9]. Little is known out the rest milk onentrtions of essentil tre elements in sujets elonging to different soioeonomi sttus. Therefore, this study determines the rest milk zin, opper nd iron onentrtions nd their possile orreltions with mternl nutritionl sttus, dietry intkes nd soioeonomi sttus. Mteril nd Methods Study Popultion In this 4Tdesriptive4T 11T-nlyti study,11t ninety ltting women were reruited from urn res of Triz- Irn who exlusively rest-fed their infnts ged dys, in April 007. The reserh smple inluded ll mothers in defined popultion of five urn helth enters who were dmitted for their infnts vintion. Helth enters inluded in this study were loted in three different SES distrits. From the dt provided y the Est Azerijn Provine Helth Center, three distrits within the metropolitn re of Triz were identified. These three distrits re inhited y itizens with distinguished SES nd onsequently this is refleted on the SES of the mothers. In ddition, mothers were reruited from these enters fter ompleting soioeonomi questionnire inluding questions out ouption sttus of husnd (mnul, non-mnul worker, unemployed, nd retired), 4Tquisition of4t house nd personl r, motorike, lk nd white TV (B/W TV), olor TV, refrigertor, freezer, vuum lener nd wshing mhine, nd sujets edution level rnging from primry shool to university degree. All mothers were tegorized in 3 soioeonomi groups (low, intermedite, nd high). The riteri for inlusion of mothers were no tre elements supplement intke, nd hve infnts who were full term nd exlusively restfed ged dys, with norml irth weight, nd with no hroni disese. The study protool ws pproved y the Ethis Committee of Triz University of Medil Siene. All sujets were informed out the ontent of the study nd if they greed to prtiipte, written informed onsent ws otined. Determintion of Tre Elements in Brest milk Brest milk (10 15 ml) smples were olleted into metl free tues y self-expression efore nursing the y in the morning. The smples were kept t 4 C nd trnsferred to zin-free, srew-p plsti tues nd frozen within 1 dy t 0 C efore extrtion. Brest milk smples were wet-shed nd nlyzed ording to Clegg et l. [10]. Smples were thwed, mixed thoroughly, nd digested in ultrpure onentrted nitri id (Fisher, 141

3 Helth Promotion Perspetives, Vol. 1, No., 011; P: Los Angeles) t room temperture for 96 h nd then t su-oiling temperture for 6 9 h. Iron, zin, nd opper onentrtions were determined y tomi sorption spetrometry (Chem Teh Anlytil-000 A.A.A.). Reovery ssys were rried out to hek the ury of the method. The reovery perentges for zin, opper, nd iron were 95.6, 97.1, nd 98., respetively. Dt Colletion from Mothers Informtion on food intke ws olleted y using 4-h rell method for 3 dys (one weekend dy inluded). Dietry intke of sujets ws nlyzed y nutritionist III softwre progrm. Demogrphi dt (i.e. ple of residene nd ge), nd linil dt (i.e. helth sttus) were otined through interview. The ody mss index (BMI) ws lulted s weight (kg) divided y height (m). Sttistil Anlysis Results re presented s men±sd vlues. Men etween groups were ompred using nlysis of vrine nd t test. Multiple liner regressions using the kwrd tehnique were used to nlyze the ssoition of eh potentil ftor with zin, opper, nd iron onentrtions in rest milk. Results Desriptive dt of 90 mothers in 3 SES groups re presented in Tle 1. The verge of BMI ws within the overweight rnge in different groups. The mothers ge in high SES group ws signifintly higher thn the moderte nd low SES groups (P<0.001). Men rest milk onentrtions nd dily dietry intke of zin, opper nd iron re shown in Tle. The men energy intke in ll 3 groups ws signifintly (P<0.05) less thn required dily intke (RDA) reommendtion (730 kl/dy). The perentge of energy from different mronutrients ws in the norml reommended rnge. Anlysis of vrine showed signifint differene in rest milk zin (P<0.004), opper (P<0.001), nd iron (P<0.048) onentrtion in three SES groups. Tukey post-ho omprisons of the three groups indited signifint differene in rest milk zin, opper nd iron onentrtion etween high nd low SES groups (Zn(P<0.001), Cu (P<0.001) nd Fe (P<0.044)) nd lso moderte nd low SES groups (Zn(P<0.03),Cu (P<0.001) nd Fe (P<0.049)). Brest milk iron nd opper ontent were in the reommended rnge [11]. Infnts less thn 6 months of ge require out mg per dy of zin. This reommended llowne orresponds to levels of 3 to 5 mg/l of zin in rest milk [11]. In ll olleted rest milk smples, the zin levels were lower thn 3 mg/l. As indited in Tle, in ll three groups, the men dietry zin nd opper intkes of mothers were signifintly less (P<0.05) thn RDA reommendtions (zin (6.1 vs. 1 mg/d), opper (1.19 vs. 1.3 mg/d)). The men dietry iron intke ws signifintly (P<0.001) higher thn RDA reommendtion (11.1 vs. 9 mg/d). No signifint differenes were found etween men dily intkes of these nutrients in SES groups. Tle 3 represents the ssoition of different ftors with rest milk minerl levels. In ll sujets, fter djusting for mternl men dietry energy, zin, opper, nd iron intkes, BMI nd SES, there ws negtive nd signifint ssoition etween mternl ge nd rest milk zin (=-0.8, P<0.034), opper (=-0.18, P<0.048), nd iron (=-0., P<0.04) onentrtions. However no signifint ssoition ws found etween mternl BMI, ge, men dietry energy, zin, opper, nd iron intkes with the zin, opper, nd iron onentrtions in mothers rest milk of eh soio eonomi groups (Tle 4). 14

4 Nikniz et l.: Mternl Body Mss Index Tle 1: Mternl Desriptive Dt in different SES (men±sd) Soioeonomi sttus Vriles Low Moderte High Totl (n=90) * Age (yr) 6.01±6.1P 7.6±4.7P 31.±6.7P 8.±5.8 Weight(kg) 65.4± ±10 67.± ±1.4 Height (m) 157.4± ± ± ±6.3 BMI (kg/mp P) 6.4± ± ± ±4.6 *(ANOVA) Signifint differene etween groups (P<0.05) *(Tukey test) Signifint differene etween (P<0.001) nd (P<0.0) Tle : Men rest milk Zn, Cu nd Fe onentrtions nd their dily dietry intke in different SES groups Soioeonomi sttus Vriles Low Moderte High Totl (n=90) * Brest milk Zn onentrtion (mg/l) 0.71P P±.3 0.7P P± P P± ±0.71 *Brest milk Fe onentrtion (mg/l) 0.1P P± P P± P P± ±0. * Brest milk Cu onentrtion (mg/l) 0.51P P± P P± P P± ±0.3 Dietry Zn intke (mg/d).5±5.8.4±6.1.±6.5.3±6.1 Dietry Fe intke(mg/d) 6.± ±11 3.1± ±5.1 Dietry Cu intke(mg/d) 0.75± ± ± ±0.7 *(ANOVA) Signifint differene etween groups (P<0.05) *(Tukey test) Signifint differene etween nd nd (P<0.05) Tle 3: The ssoition of different ftors with rest milk Zn, Cu nd Fe levels Vriles Brest milk Zn ontent Brest milk Cu ontent Brest milk Fe ontent P-vlue P-vlue P-vlue Dily energy intke (Kl) Mternl BMI(kg/mP P) Mternl ge (Yer) * * * Soioeonomi sttus High Moderte Low Dietry Zn intke (mg/d) Dietry Cu intke (mg/d) Dietry Fe intke (mg/d) *Signifint orreltion etween mternl ge nd rest milk Zn, Cu nd Fe onentrtion fter djusting for dily energy, Zn, Cu nd Fe intke, mternl BMI nd Soioeonomi sttus 143

5 Helth Promotion Perspetives, Vol. 1, No., 011; P: Tle 4: The ssoition of different ftors with rest milk Zn, Cu nd Fe levels in different SES groups Vriles Dily energy intke (Kl) Mternl BMI (kg/mp P) Mternl ge (yr) Dietry Zn intke (mg/d) DietryCu intke (mg/d) Dietry Fe intke (mg/d) Zn Cu Brest milk minerl levels in different soioeonomi sttus (mg/l) Low Moderte High Fe Zn Cu Fe Zn Cu Fe Disussion In our study, men zin onentrtion (1.93± 0.71 mg/l) ws lower thn 4.1 mg/l reported in 1 0 weeks postprtum for Austri [1], mg/l for Cnd [13],.0 mg/l for Texs [14]. The opper levels of mothers rest milk (0.58±0.3 mg/l) were higher thn the levels reported elsewhere whih ws mg/l in Kore [15] nd mg/l in Tiwn [16], ut it ws lower thn the reported vlues (0.86 mg/l) from Austri [1]. Men iron onentrtion (0.81±0. mg/l) ws higher thn vlues (0.46 mg/l) reported for Austri [1] nd mg/l for Tiwn [16]. The dt for tre element ontent of humn milk differ widely from region to region. Vritions of tre element onentrtions in rest milk my e due to differenes in smpling, nlytil tehniques, dietry intke, type nd dose of tre element supplementtion, nd lso soioeonomi sttus of sujets [3,8]. In this study, rest milk zin, opper nd iron onentrtion in high SES group ws signifintly lower thn Low SES group nd lso it ws insignifintly lower thn moderte SES group. The results of study in Indi showed tht the opper nd zin onentrtions in 144

6 Nikniz et l.: Mternl Body Mss Index mother s milk from the low-inome group were lower thn tht of the high-inome group [4]. To justify this differene, it seems tht BMI of Indin mothers elonging to the low SES ws extremely lower thn BMI of sujets elonging to low SES group in this study. However, similr results were found in the study onduted y Domellöf et l. who showed tht the Hondurn mothers elonging to low soioeonomi sttus who were younger thn Swedish mothers hd signifintly higher rest milk zin nd opper onentrtions [6]. Similr to the Domellöf et l. study, our sujets elonging to the low SES group were younger thn the others. Besides, negtive nd signifint orreltion etween mternl ge nd rest milk tre elements onentrtion ws seen. Therefore, it ould e proposed tht mternl ge is one of the importnt ftors ffeting rest milk tre element onentrtion. We ould not find ny other humn study evluting the effet of mternl ge on tre elements onentrtion in rest milk ut some niml studies hve shown ge relted redution in intestinl sorption of zin nd opper whih my e due to hnges in gene expression of trnsfer proteins nd inresed holesterol in intestinl epithelil ells [17, 18]. Dietry zin, opper, nd iron intkes of our sujets in three SES groups were lower thn the dietry intke of the Amerin nd Neplese mothers [19]. Similr to the results of the most previous studies [6, 9, 0-1], there ws no orreltion etween mternl dietry zin opper, nd iron intke nd rest milk zin, opper, nd iron onentrtion whih my e euse of tive trnsport mehnisms in the mmmry glnd for ll three minerls. As onlusion, the onentrtion of studied tre elements in milk of mothers with low SES ws higher thn moderte nd high SES. The oserved signifint orreltion etween rest milk minerl onentrtions nd mternl ge ut not intke suggest tht mothers ge ws one of the importnt ftors ffeting rest milk tre element onentrtion. Hene more studies re needed to lrify the mehnisms mothers ge ffeting rest milk tre element onentrtion. In ddition, more trils re needed to determine whether Irnin diet ould supply zin lone or whether supplementl zin should e given to infnts efore 4 months old nd/or whether, fter 4 months, omplementry food should e fortified with zin. Aknowledgments The uthors wish to thnk the Triz Peditri Helth Reserh Center for finnil support. This study would not hve een possile without the help nd prtiiption of the helth enters nd ll the mothers who volunteered their milk smples. This rtile ws written sed on dtset of MS thesis, registered in Triz University of Medil Sienes. The uthors delre tht there is no onflit of interests. Referenes [1] World Helth Assemly. Infnt nd young hild nutrition. Resolution WHA 54., 001. [] Trhms C, Mken K. Nutrition during infny. In: Kthleen Mhn L, Esott Stump S, editors. Kruse s food, nutrition, nd diet therpy. 11th ed. Sunders: Phildelphi; 008. [3] Frid M, Al-Awdi STS. Treelement sttus in milk nd plsm of Kuwiti nd non-kuwiti ltting mothers. Nutrition 000; 16: [4] Rjlkshmi K, Sriknti SG. Copper, zin, nd mgnesium ontent of rest milk of Indin women. Am J Clin Nutr 1980; 33: [5] Domellöf M, Hernell O. Iron-defiieny nemi during the first two 145

7 Helth Promotion Perspetives, Vol. 1, No., 011; P: yers of life. Snd J Nutr 00; 46: [6] Domellöf M, Lönnerdl B, Dewey KG et l. Iron, zin, nd opper onentrtions in rest milk re independent of mternl minerl sttus. Am J Clin Nutr 004; 79: [7] Piino MF. Pregnny nd lttion: physiologil djustments, nutritionl requirements nd the role of dietry supplements. J Nutr 003; 133:1997. [8] Mhdvi R, Nikniz l, Gyemmgmi SJ. Assoition etween Zin, Copper, nd Iron Conentrtions in Brest Milk nd Growth of Helthy Infnts in Triz, Irn. Biol Tre Elem Res 010; 135: [9] Lönnerdl B. Effets of mternl dietry intke on humn milk omposition. J Nutr 1986; 116: [10] Clegg MS, Keen CL, Lönnerdl B et l. Influene of shing tehniques on the onentrtion of tre elements in niml tissues. 1: wet shing. Biol Tre Elem Re 1981; 3: [11] Piino MF, MDonld SS. Lttion. In: Shills ME, editor. Modern nutrition in helth nd disese. 10th ed. Kluwer: Phildelphi; 006. [1] Krhler M, Li FS, Rossipl E, Irgoli KJ. Chnges in the onentrtion of tre elements in humn milk during lttion. J Tre Elem Med Biol 1998; 1: 159. [13] Friel JK, Andrews WL, Jkson SE et l. Elementl omposition of humn milk from mothers of premture nd full-term infnts during the first 3 months of lttion. Biol Tre Elem Res1999; 67: 5. [14] Hnnn MA, Frji B, Tngum J et l. Mternl milk onentrtion of zin, iron, selenium, nd iodine nd its reltionship to dietry intkes. Biol Tre Elem Res 009; 17: [15] Ko YS, Om AS. Anlysis of the onentrtions of tre elements in olostrum, trnsitionl nd mture milk of Koren women. J Tre Elem Exp Med 1998; 11: 407. [16] Lin TH, Jong YJ, Ching CH, Yng MH. Longitudinl hnges in lium, mgnesium, iron, opper nd zin in rest milk of women in Tiwn over lttion period of one yer. Biol Tre Elem Res 1998; 6: 31. [17] Coudry F, Rmeu M, Clude Tressol J, Gueux E, Mzur A, RyssiguierY. The effet of ging on intestinl sorption nd sttus of lium, mgnesium, zin, nd opper in rts: A stle isotope study. J Tre Elem Med Biol 006; 0: [18] Teillet L, Tnet F, Ripohe P, Cormn B. Effet of ging on zin nd histidine trnsport ross rt intestinl rush-order memrnes. Meh Ageing Dev 1995; 14: [19] Moser PB, Reynolds RD, Ahry S et l. Copper, iron, zin, nd selenium dietry intke nd sttus of Neplese ltting women nd their rest-fed infnts. Am J Clin Nutr 1998; 47: [0] Moser PB, Reynolds RD. Dietry zin intke nd zin onentrtions of plsm, erythroytes, ndrest milk in nteprtum nd postprtum ltting nd nonltting women: longitudinl study. Am J Clin Nutr 1983; 38: [1] Celd A, Busset R, Gutierrez J et l. No orreltion etween iron onentrtion in rest milk nd mternl iron stores. Helv Peditr At 198; 37: