Abstract

The aim of this study was to analyze the association between breastfeeding type in the first six months of life and intake of vitamin A and iron in children 6-12 months of age. It is a cohort study with 226 children. The type of breastfeeding from 1-6 months of life and the food intake from 6 to 12 months were evaluated. Nutrient intake between groups was compared by the Kruskal-Wallis test. The association between nutrient intake and type of breastfeeding was analyzed by Poisson Regression. Consumption below the recommendation of vitamin A and iron was 33.6% and 67.7%, respectively. Infants exclusively and predominantly breastfed from birth to two months had higher vitamin A intake from 6-12 months of life. Infants who were breastfeeding at 6 months had higher vitamin A intake and lower iron by the bivariate analysis. The group that received mixed feeding and artificial feeding at 1 month and the group non-breastfed at 6 months had vitamin A intake below the recommended from 6-12 month of life. The results reinforce the importance of exclusive breastfeeding in the first six months of life contributing to the higher vitamin A intake. Iron intake was lower among breastfed children, but the bioavailability of this nutrient in breast milk is higher.

Keywords
Breastfeeding; Vitamin A; Iron

Introduction

Infant feeding, from birth to the first year of age, influences child health throughout life¹1 Lima APE, Javorski M, Amorim RJM, Oliveira SC, Vasconcelos MGL. Práticas alimentares no primeiro ano de vida: representações sociais de mães adolescentes. Rev Bras Enferm 2014;67(6):965-971.. Knowing that breastfeeding is critical for infant feeding, the World Health Organization (WHO) recommends exclusive breastfeeding (EBF) for the first 6 months of life and complementary foods up to 2 years of age²2 World Health Organization (WHO). Report of an expert consultation on the optimal duration of exclusive breastfeeding. Geneva: WHO; 2001.^,33 Brasil. Ministério da Saúde (MS). Secretaria de Atenção à Saúde. Departamento de Atenção Básica. Saúde da criança: aleitamento materno e alimentação complementar. 2ª Edição. Brasília: MS; 2015..

Early introduction of complementary foods may shorten breastfeeding duration and cause some nutrients to be poorly absorbed, e.g. vitamin A and iron, leading to the development of nutritional deficiencies⁴4 Brasil. Ministério da Saúde. Secretaria de Atenção à Saúde. Departamento de Atenção Básica. Saúde da criança: nutrição infantil: aleitamento materno e alimentação complementar. Brasília: MS; 2009.

5 Dias CAP, Freire LMS, Franceschini SCC. Recomendações para alimentação complementar de crianças menores de dois anos. Rev. Nutr 2010; 23(3):475-486.^-66 Alves CRL, Santos LC, Goulart LMHF, Castro PR. Alimentação complementar em crianças no segundo ano de vida. Rev. Paul. Pediatr 2012;30(4):499-506.. Iron and vitamin A deficiencies in children are considered a public health problem⁷7 Mariath AB, Giachini RM, Lauda LG, Grillo LP. Estado de ferro e retinol sérico entre crianças e adolescentes atendidos por equipe da Estratégia Saúde da Família de Itajaí, Santa Catarina. Ciên Saúde Colet 2010;15(2):509-516.^,88 Silva MA, Carvalho CA, Fonsêca PCA, Vieira AS, Ribeiro AQ, Priore SE, Franceschini ACC. Prevalência e fatores associados à anemia ferropriva e hipovitaminose A em crianças menores de um ano. Cad Saude Colet 2015;23(4):362-367.. Data from the National Demographic and Health Survey (PNDS) show that the prevalence of iron deficiency anemia and vitamin A deficiency among children under five was 20.9% and 17.4%, respectively⁹9 Brasil. Ministério da Saúde (MS). Pesquisa Nacional de Demografia e Saúde da Criança e da Mulher (PNDS) 2006: dimensões do processo reprodutivo e da saúde da criança [livro na Internet]. Brasília: MS; 2009 [acessado 2016 Mai]. Disponível em: http://bvsms.saude.gov.br/bvs/publicacoes/pnds_crianca_mulher.pdf
http://bvsms.saude.gov.br/bvs/publicacoe... .

The association between breastfeeding in the first six months of life and the formation of healthy eating habits in childhood is still controversial. Studies indicate that breastfeeding has a direct influence on food acceptance in later life¹⁰10 Burnier D, Dubois L, Girard M. Exclusive breastfeeding duration and later intake of vegetables in preschool children. Eur J Clin Nutr 2011;65(2):196-202.^,1111 Soldateli B, Vigo A, Giugliani ERJ. Effect of pattern and duration of breastfeeding on the consumption of fruits and vegetables among preschool children. PloS One 2016;11(2):1-8., indicating that children who have been breastfed have greater acceptance of fruits and vegetables¹²12 Lauzon-Guillain B, Jones L, Oliveira A, Moschonis G, Betoko A, Lopes C, Moreira P, Manios Y, Papadopoulos NG, Emmett P, Charles MA. The influence of early feeding practices on fruit and vegetable intake among preschool children in 4 European birth cohorts. Am J Clin Nutr 2013;98:1-9.. This feeding practice is believed to influence iron and vitamin A intake after the introduction of complementary foods¹³13 Perrine CG, Galuska DA, Thompson MPH, Scanlon KS. Breastfeeding Duration Is Associated With Child Diet at 6 Years. Pediatrics 2014;134(1):850-855.. However, Valmórbida and Vitolo¹⁴14 Valmórbida JL, Vitolo MR. Factors associated with low consumption of fruits and vegetables by preschoolers of low socio-economic level. J Pediatr (Rio J) 2014;90(5):464-471. found no association between breastfeeding and later eating practices in childhood. Thus, the objective of this study was to evaluate whether breastfeeding in the first six months of life is related to vitamin A and iron intake in children aged 6 to 12 months.

Methodology

This is a cohort study with children followed up from birth to 12 months of life, conducted between 2011 and 2013. The invitation to participate in the study was performed at the maternity hospital in the city of Viçosa-MG, at the time of birth. The sample consisted of 226 children of both sexes, followed in the Municipal Immunization Departmentof Viçosa-MG. This service is considered a reference for performing the Guthrie test, which facilitated recruitment of mothers for the study.

The inclusion criterion was that the child resided within the city limits of Viçosa, MG. The exclusion criteria were: regular use of medications or some clinical health alteration that could interfere with the nutritional status and alter the child’s diet. The sample flowchart is shown in Figure 1.

Follow-up losses were assessed for the possibility of selection bias up to the sixth month of follow-up. No differences were found between followed children and lost children when comparing sociodemographic characteristics, number of prenatal consultations, birth variables such as birth weight and length, and use of pacifier, according to data presented by Fonseca et al.¹⁵15 Fonseca PCA, Carvalho CA, Ribeiro SAV, Nobre LN, Pessoa MC, Ribeiro AQ, Priore SE, Franceschini SDCC. Determinants of the mean growth rate of children under the age of six months: a cohort study. Ciên Saude Colet 2016;22(8):2713-2726. and Carvalho et al.¹⁶16 Carvalho CA, Ribeiro SAV, Nobre LN, Pessoa MC, Ribeiro AQ, Priore SE, Franceschini SCC. Fatores sociodemográficos, perinatais e comportamentais associados ao tipo de leite consumidos por crianças menores de seis meses: coorte de nascimento. Ciên Saude Colet 2017;22(8):2713-2726..

The sample size was calculated for this study using the OpenEpi Program considering the total number of children (806) born in Viçosa during data collection and the prevalence of outcomes (vitamin A intake below recommendation - 33.3%, and iron - 67.7%, for children 6-12 months). For a 95% confidence level, the sample size calculated was 237 and 249, considering the prevalence of food intake below the recommendation for iron and vitamin A, respectively. The sample (226) of children aged 6-12 months, followed since birth, corresponded to 91% of the largest sample calculated (249 children).

During the interview, a semi-structured questionnaire was applied containing questions regarding the child’s birth conditions and socioeconomic status. The consumption of breast milk, infant formulae, and bovine milk was evaluated at the first, second, fourth, and sixth month, when the children were taken to the polyclinic for vaccination.

Mothers or guardians (hardly ever guardians) of the children responded to a 24-hour recall at the 6, 9, or 12 months of life. After the first 6 months of life, only one more meeting was held on the 9^th or the 12^th month. Therefore, whether there was a difference in the dietary intake of iron and vitamin A was evaluated in children aged 6-12 months, according to the breastfeeding pattern in the first six months of life. Losses during the assessment of food intake occurred due to some mothers not being able to report their children’s consumption when they attended day-care centers full time and/or had babysitters.

The breastfeeding pattern definitions used in this study followed the Ministry of Health²2 World Health Organization (WHO). Report of an expert consultation on the optimal duration of exclusive breastfeeding. Geneva: WHO; 2001.: Exclusive Breastfeeding (EBF) - infant receives breast milk only directly from the breast or pumped, or breast milk from donor sources, and no other solids or liquids except syrups, mineral supplements, or medicines. Predominant Breastfeeding (PBF) - infant receives, in addition to breast milk, water or water-based drinks (teas, infusions), and fruit juices. Complementary feeding - infant receives, in addition to breast milk, solid or semi-solid foods as a complement to breast milk, not to replace it. Mixed feeding (MF) - infant receives breast milk, infant formula, and other types of milk. Due to the low prevalence of PBF, we considered the intake values of this pattern together with the EBF.

Food intake data were entered into the Avanutri® software. The Food Composition Table (TACO)¹⁷17 Tabela Brasileira de Composição de Alimentos (TACO). 4ª Edição revisada e ampliada. Campinas, SP: UNICAMP; 2011. Disponível em: http://www.unicamp.br/nepa/taco/contar/taco_4_edicao_ampliada_e_revisada.pdf?arquivo=taco_4_versao_ampliada_e_revisada.pdf
http://www.unicamp.br/nepa/taco/contar/t... , 4^th version, was selected for this study. Foods not found in the program were registered and the ingredient lists were standardized in order not to underestimate or overestimate the amount of vitamin A and iron ingested. Nutrient intake was compared to the Dietary Reference Intakes (DRI)¹⁸18 Institute Of Medicine/Food And Nutrition Board. Dietary References Intakes for vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium and zinc. Washington: National Academy Press; 2001.. Vitamin A was quantified in Retinol Equivalent (RE) by the software, but was converted to micrograms for purposes of analysis.

The prevalence of inadequate iron intake was calculated using Adequate Intake (AI) for 6-month-old children (AI = 0.27 mg) and Estimated Average Requirement (EAR) for 7-12-month-old children (EAR = 6.9 mg). Regarding vitamin A, AI = 400 µg was considered for 6 months old children and AI = 500 µg for 7-12 months old children. EAR was used as a reference and when not available, we used AI instead. Nutrients were adjusted by diet energy density using the waste method¹⁹19 Willett W. Nutritional epidemiology. 2ª Edição. New York: Oxford; 1998.. This method estimates the fraction of nutrients that do not correlate with total energy intake²⁰20 Slater B, Marchioni DML, Voci SM. Aplicação de regressão linear para correção de dados dietéticos. Rev Saude Publica 2007;41(2):190-196.. We considered the intake of iron and vitamin A from the diet, while the intake of dietary supplements was not taken into account, since it was not included in the recalls.

We estimated the amount of breast milk consumed by the children who were breastfeeding at the time of the food recall application to avoid underestimation of food intake, using the methodology proposed by WHO/UNICEF²¹21 World Health Organization (WHO). United Children's Fund (WHO/UNICEF). Consultation on complementary feeding in Montpellier. Subsídios preprados pela WHO e UNICEF. Montpellier: WHO; 1995..

We conducted a descriptive analysis to determine measures of central tendency and measures of dispersion. Comparisons between breastfeeding patterns and nutrient intake were analyzed by the Kruskal-Wallis test. The analysis of breast milk consumption at 6 months was performed by Student’s t test.

The bivariate analysis estimated the Relative Risk (RR).The confidence interval was estimated by Poisson Regression with robust variance. Variables with p <0.20 were included in the multiple model. In the regression analysis, the variable food intake was adjusted by current breastfeeding, child age, child skin color, mother’s education, and family income. The software application used to analyze the data was Stata version 12.0 and the statistical significance considered was α = 0.05.

The study was approved by the Research Ethics Committee of the Federal University of Viçosa, and funded by the Minas Gerais State Research Support Foundation.

Results

In this study, among the children evaluated (n = 226), 50.4% were male, 35.0% were six months of age, 32.3% were nine months of age, and 32.7% were one year of age. We found that 33.6% of children had vitamin A intake below the recommendation, while 67.7% had iron intake below the recommendation. The children’s mothers were on average 26 years old and most had more than nine years of schooling (65.0%). Using the socioeconomic classification by ABEP, 78.3% of the families were classified as categories C, D, and E.

Exclusive or predominant breastfeeding in the first month of life was recorded for 77.9% of the children evaluated. These children had higher median vitamin A intake from 6-12 months of life. The median iron intake among children who were exclusively or predominantly breastfed at 1 month was lower than those who were on artificial feeding (AF) (Table 1).

The pattern of breastfeeding the child received at 4 months of life did not interfere with iron and vitamin A intake from 6-12 months of life (Table 2). Breastfed children at six months of age had higher median vitamin A intake and lower iron intake (p <0.001) (Table 3).

The multiple analysis showed that children receiving mixed feeding MF (RR: 1.65; 95% CI: 1.07 - 2.60) and artificial feeding AF (RR: 1.97; 95% CI: 1.10 - 3.58) at 1 month of life, while those who were not breastfed at 6 months (RR: 1.81; 95% CI: 1.10 - 2.99) had a higher risk of vitamin A intake below AI. No significant association was found for iron as a function of breastfeeding pattern (Table 4).

Discussion

This study evaluated the influence of breastfeeding in the first six months of life on the intake of vitamin A and iron in children 6-12 months of age. Infants exclusively or predominantly breastfed at 1 month of life had higher vitamin A intake and lower iron intake after the introduction of complementary feeding. However, no association was found between the pattern of breastfeeding at 6 months and iron intake from 6-12 months of life.

More than a third of the children had lower than recommended vitamin A and iron intake. This prevalence was lower than the reports by Fidelis and Osório²²22 Fidelis CMF, Osório MM. Consumo alimentar de macro e micronutrientes de crianças menores de cinco anos no Estado de Pernambuco, Brasil. Rev Bras Saude Matern Infant 2007;7(1):63-74., which found vitamin A intake below the recommended in 44% of children evaluated in the State of Pernambuco and 59.5% in cities in the metropolitan region of Recife. In the same study, 65% of children had inadequate iron intake in Pernambuco, while 38.1% of children in the metropolitan region of Recife had inadequate iron intake. Freiberg et al.²³23 Freiberg CK, Philippi ST, Leal GVS, Martinez MF, Silva MEW. Avaliação do consumo alimentar de crianças menores de dois anos institucionalizadas em creches no município de São Paulo. Rev Assoc Bras Nutr 2012;4(5):17-21. conducted a study in São Paulo and found among children 6-12 months prevalence of vitamin A adequacy of 29.5% and 52.2% for iron intake.

In this study, children who were on mixed feeding, artificial feeding, and no breastfeeding at 6 months of life had a higher risk of vitamin A intake below AI from 6 to 12 months of life. Kurihayashi et al.²⁴24 Kurihayashi AY, Augusto RA, Escaldelai FMD, Martini LA. Estado nutricional de vitaminas A e D em crianças participantes de programa de suplementação alimentar. Cad Saude Publica 2015;31(3):531-542. found a positive association between breastfeeding time and serum retinol concentrations in children aged 2 to 7 years. Children who were exclusively breastfed for a period greater than or equal to 4 months presented higher serum retinol concentration²⁴24 Kurihayashi AY, Augusto RA, Escaldelai FMD, Martini LA. Estado nutricional de vitaminas A e D em crianças participantes de programa de suplementação alimentar. Cad Saude Publica 2015;31(3):531-542..

Fruit and vegetables are the major sources of vitamin A, and some studies indicate a positive association between breastfeeding and consumption of these food groups¹⁰10 Burnier D, Dubois L, Girard M. Exclusive breastfeeding duration and later intake of vegetables in preschool children. Eur J Clin Nutr 2011;65(2):196-202.

11 Soldateli B, Vigo A, Giugliani ERJ. Effect of pattern and duration of breastfeeding on the consumption of fruits and vegetables among preschool children. PloS One 2016;11(2):1-8.

12 Lauzon-Guillain B, Jones L, Oliveira A, Moschonis G, Betoko A, Lopes C, Moreira P, Manios Y, Papadopoulos NG, Emmett P, Charles MA. The influence of early feeding practices on fruit and vegetable intake among preschool children in 4 European birth cohorts. Am J Clin Nutr 2013;98:1-9.^-1313 Perrine CG, Galuska DA, Thompson MPH, Scanlon KS. Breastfeeding Duration Is Associated With Child Diet at 6 Years. Pediatrics 2014;134(1):850-855.. A longer exclusive breastfeeding and, consequently, a delay in the use of infant formulas, was associated with a higher intake of vegetables at five years of age²⁵25 Moller LM, Hoog ML, van Eijsden M, Gemke RJ, Vrijkotte TG. Infant nutrition in relation to eating behaviour and fruit and vegetable intake at age 5 years. Br J Nutr 2013;109:564-571.. This finding is attributed to the variety of flavors in breast milk. Thus, children who are breastfed recognize these flavors later in life and have greater food acceptance²⁵25 Moller LM, Hoog ML, van Eijsden M, Gemke RJ, Vrijkotte TG. Infant nutrition in relation to eating behaviour and fruit and vegetable intake at age 5 years. Br J Nutr 2013;109:564-571.^,2626 World Health Organization (WHO). Global prevalence of vitamin A deficiency in populations at risk 1995-2005: WHO global database on vitamin A deficiency. Geneva: WHO; 2009.. In addition, it is expected that mothers who are concerned with following breastfeeding recommendations will also have a healthier lifestyle and pay attention to the recommendation to introduce complementary foods¹¹11 Soldateli B, Vigo A, Giugliani ERJ. Effect of pattern and duration of breastfeeding on the consumption of fruits and vegetables among preschool children. PloS One 2016;11(2):1-8.^,2525 Moller LM, Hoog ML, van Eijsden M, Gemke RJ, Vrijkotte TG. Infant nutrition in relation to eating behaviour and fruit and vegetable intake at age 5 years. Br J Nutr 2013;109:564-571..

Early introduction of complementary foods is associated with lower nutrient intake and increased vulnerability of children to diarrhea and infections, leading to a compromised nutritional status of vitamin A²⁷27 Araújo MFM, Fiaco AD, Pimentel LS, Schmitz BAS. Custo e economia da prática do aleitamento materno para a família. Rev Bras Saude Matern Infant 2004;4(2):135-141.. Children in the present study had lower intake of this nutrient when not breastfed as recommended, being more exposed to the risk of a possible deficiency.

Expenditure on infant formulas is estimated at approximately 35% of the minimum wage, while on bovine milk is at 11%²⁸28 Schincaglia RM, Oliveira AC, Sousa LM, Martins KA. Práticas alimentares e fatores associados à introdução precoce da alimentação complementar entre crianças menores de seis meses na região noroeste de Goiânia. Epidemiol Serv Saude 2015;24(3):465-474.. Breastfeeding is a more economical option for the family, and contributes to that most of the income goes to spending on other foods, especially vitamin A sources such as fruit and vegetables. Therefore, exclusively or predominantly breastfed children would tend to have a better quality diet, with a greater supply of vitamin A source foods⁴4 Brasil. Ministério da Saúde. Secretaria de Atenção à Saúde. Departamento de Atenção Básica. Saúde da criança: nutrição infantil: aleitamento materno e alimentação complementar. Brasília: MS; 2009..

In this study we observed a positive influence of breastfeeding in the first 6 months of life on children’s food intake from the beginning of complementary feeding to the end of the first year of life. The median intake of iron and vitamin A differed significantly between breastfeeding groups at all times evaluated.

Iron consumption was higher after six months in the group that was breastfed at1 month of life. This finding can be explained by the fact that children who are not breastfed tend to an early introduction of complementary feeding, with early access to iron source foods, meat for instance²⁹29 Bortolini GA, Vitolo MR. Importância das práticas alimentares no primeiro ano de vida na prevenção da deficiência de ferro. Rev Nutr 2010;23(6):1051-1062.. Nevertheless, it is important to consider the influence of confounders in the bivariate analysis, in which the medians between groups were simply compared. When the confounding variables for adjustment were included in the multivariate analysis, we found no difference in the prevalence of low iron intake from 6-12 months of life between breastfeeding patterns in the first 6 months.

Iron bioavailability in breast milk can be reduced by up to 80% when other foods are introduced³⁰30 Ferreira S, Pinto M, Carvalho P, Gonçalves JP, Lima R, Pereira F. Alergia às proteínas do leite de vaca com manifestações gastrointestinais. Revista de Pediatria do Centro Hospitalar do Porto 2014;23(2):72-79.. Hence, the importance of exclusive breastfeeding in the first six months of life is emphasized with respect to the adequate intake of this micronutrient.

The early introduction of other milks may change the intestinal mucosal permeability in infants, triggering problems such as allergies, iron deficiency anemia, renal overload, and deficiency of vitamins, minerals, and essential fats (omega 3 and omega 6)²⁹29 Bortolini GA, Vitolo MR. Importância das práticas alimentares no primeiro ano de vida na prevenção da deficiência de ferro. Rev Nutr 2010;23(6):1051-1062.^,3131 Machado AKF, Elert VW, Pretto AD, Pastore CA. Intenção de amamentar e de introdução de alimentação complementar de puérperas de um Hospital Escola do Sul do Brasil. Ciên Saude Colet 2014;19(7) 1983-1989.^,3232 Costa EC, Silva SP, Lucena JR, Batista Filho M, Lira PI, Ribeiro MA, Osório MM. Food consumption of children from cities with a low human development index in the Brazilian Northeast. Rev Nutr 2011;24:395-405.. Besides, breast milk can supply the child’s physiological iron needs when exclusively supplied in the first six months, given its high bioavailability when compared with other types of milk. About 50% of iron ingested through breast milk is absorbed, whereas in bovine milk only 10% of the iron is consumed³⁰30 Ferreira S, Pinto M, Carvalho P, Gonçalves JP, Lima R, Pereira F. Alergia às proteínas do leite de vaca com manifestações gastrointestinais. Revista de Pediatria do Centro Hospitalar do Porto 2014;23(2):72-79..

Finally, a number of limitations of this study need to be considered. The considerable follow-up losses are common in cohort studies. In this sense, a sample size was calculated, showing that there was enough sample to study the influence of breastfeeding on the worse food intake in children 6-12 months of life. Moreover, there was no differential bias when comparing the followed up children with those lost in the first six months. Complementary feeding data were obtained from only one 24-hour recall, which made it impossible to perform nutrient adjustment by intraindividual variability. However, we found that the feeding of children in this age group was monotonous, allowing the use of a single recall. In addition, other studies used only one food survey to assess nutrient intake in children³³33 Silva JV, Timóteo AK, Santos CD, Fontes G, Rocha EM. Food consumption of children and adolescents living in an area of invasion in Maceio, Alagoas, Brazil. Rev Bras Epidemiol 2010;13:83-93.^,3434 Menezes RCE, Osório MM. Consumo energético-proteico e estado nutricional de crianças menores de cinco anos, no estado de Pernambuco, Brasil. Revista de Nutrição 2007;20(4):337-347.. Combining the children in exclusive and predominant breastfeeding was necessary because the children in predominant breastfeeding were less frequent. However, it is of note that the benefits of exclusive breastfeeding compared with the other patterns are unquestionable.

Nonetheless, the relevance of this study is emphasized by the investigation of the relationship between breastfeeding pattern and micronutrient intake in the first year of life, considering that this association is little studied. In clinical practice, the findings of this study reinforce the importance of breastfeeding in the formation of healthier eating habits and contribute to the prevention of diseases associated with poor diet in childhood. In other terms, in addition to the numerous benefits of breastfeeding for child health³3 Brasil. Ministério da Saúde (MS). Secretaria de Atenção à Saúde. Departamento de Atenção Básica. Saúde da criança: aleitamento materno e alimentação complementar. 2ª Edição. Brasília: MS; 2015., this feeding practice positively influences food preferences in later stages¹³13 Perrine CG, Galuska DA, Thompson MPH, Scanlon KS. Breastfeeding Duration Is Associated With Child Diet at 6 Years. Pediatrics 2014;134(1):850-855..

In conclusion, more than one third of the children had below the recommendation vitamin A and iron intakes. Children who exclusively or predominantly breastfed in the first 6 months of life had a higher frequency of adequate vitamin A intake. Iron intake was lower among breastfed children, but the bioavailability of this nutrient in breast milk is higher. These findings reinforce the importance of public policies with the maternal and child group to encourage exclusive breastfeeding and the correct introduction of complementary feeding.

Aknowledgements

The authors thank the Minas Gerais State Research Support Foundation - Fapemig.

References

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