Cultural determinants of optimal breastfeeding practices among indigenous Mam-Mayan women in the Western Highlands of Guatemala

Human milk microbiome: associations with maternal diet and infant growth

Introduction

Ingestion of human milk (HM) is identified as a significant factor associated with early infant gut microbial colonization, which has been associated with infant health and development. Maternal diet has been associated with the HM microbiome (HMM). However, a few studies have explored the associations among maternal diet, HMM, and infant growth during the first 6 months of lactation.

Methods

For this cross-sectional study, Mam-Mayan mother-infant dyads (n = 64) were recruited from 8 rural communities in the Western Highlands of Guatemala at two stages of lactation: early (6-46 days postpartum, n = 29) or late (109-184 days postpartum, n = 35). Recruited mothers had vaginally delivered singleton births, had no subclinical mastitis or antibiotic treatments, and breastfed their infants. Data collected at both stages of lactation included two 24-h recalls, milk samples, and infant growth status indicators: head-circumference-for-age-z-score (HCAZ), length-for-age-z-score (LAZ), and weight-for-age-z-score (WAZ). Infants were divided into subgroups: normal weight (WAZ ≥ -1SD) and mildly underweight (WAZ < -1SD), non-stunted (LAZ ≥ -1.5SD) and mildly stunted (LAZ < -1.5SD), and normal head-circumference (HCAZ ≥ -1SD) and smaller head-circumference (HCAZ < -1SD). HMM was identified using 16S rRNA gene sequencing; amplicon analysis was performed with the high-resolution ANCHOR pipeline, and DESeq2 identified the differentially abundant (DA) HMM at the species-level between infant growth groups (FDR < 0.05) in both early and late lactation.

Results

Using both cluster and univariate analyses, we identified (a) positive correlations between infant growth clusters and maternal dietary clusters, (b) both positive and negative associations among maternal macronutrient and micronutrient intakes with the HMM at the species level and (c) distinct correlations between HMM DA taxa with maternal nutrient intakes and infant z-scores that differed between breast-fed infants experiencing growth faltering and normal growth in early and late lactation.

Conclusion

Collectively, these findings provide important evidence of the potential influence of maternal diet on the early-life growth of breastfed infants via modulation of the HMM.

Human milk microbial species are associated with infant head-circumference during early and late lactation in Guatemalan mother-infant dyads

Human milk contains abundant commensal bacteria that colonize and establish the infant's gut microbiome but the association between the milk microbiome and head circumference during infancy has not been explored. For this cross-sectional study, head-circumference-for-age-z-scores (HCAZ) of vaginally delivered breastfed infants were collected from 62 unrelated Mam-Mayan mothers living in eight remote rural communities in the Western Highlands of Guatemala during two stages of lactation, 'early' (6-46 days postpartum, n = 29) or 'late' (109-184 days postpartum, n = 33). At each stage of lactation, infants were divided into HCAZ ≥ -1 SD (early: n = 18; late: n = 14) and HCAZ < -1 SD (early: n = 11; late: n = 19). Milk microbiome communities were assessed using 16S ribosomal RNA gene sequencing and DESeq2 was used to compare the differential abundance (DA) of human milk microbiota with infant HCAZ subgroups at both stages of lactations. A total of 503 ESVs annotated 256 putative species across the 64 human milk samples. Alpha-diversity using Chao index uncovered a difference in microbial community richness between HCAZ ≥ -1 SD and HCAZ < -1 SD groups at late lactation (p = 0.045) but not at early lactation. In contrast, Canonical Analysis of Principal Coordinates identified significant differences between HCAZ ≥ -1 SD and HCAZ < -1 SD at both stages of lactation (p = 0.003); moreover, 26 milk microbial taxa differed in relative abundance (FDR < 0.05) between HCAZ ≥ -1 SD and HCAZ < -1 SD, with 13 differentially abundant at each lactation stage. Most species in the HCAZ ≥ -1 SD group were Streptococcus species from the Firmicutes phylum which are considered human colonizers associated with human milk whereas the HCAZ < -1 SD group at late lactation had more differentially abundant taxa associated with environmentally and 'potentially opportunistic' species belonging to the Actinobacteria genus. These findings suggest possible associations between brain growth of breastfed infants and the milk microbiome during lactation. Importantly, these data provide the first evidence of cross talk between the human milk microbiome and the infant brain that requires further investigation.

Human milk microbiome is shaped by breastfeeding practices

There is evidence that breastfeeding practices may impact the milk microbiota diversity and differential abundance at the genera level; however, the possibility that distinct feeding practices, such as exclusive (EBF) and non-exclusive breastfeeding (non-EBF), might alter the milk microbiome at the species level has not been explored. This cross-sectional study analyzed the milk microbiome of 64 Mam-Mayan indigenous mothers from San Juan Ostuncalco in Guatemala. Two breastfeeding practices [exclusive (EBF) vs non-exclusive (non-EBF)] were analyzed at two stages of lactation [early (5–46 days post-partum) vs late (109–184 days post-partum)]. EBF was defined as offering only human milk and non-EBF was defined as feeding the infant herbal teas (agüitas) and/or complementary foods while continuing to breastfeed. Results identified four clusters with distinct microbial communities that segregated bacterial species by both breastfeeding practices and stage of lactation. Comparison among these clusters identified several notable patterns. First, during EBF, the microbiome differed by stage of lactation where there was a shift in differential abundance from Actinobacteria and Firmicutes in early to Bacteroidetes and Proteobacteria species in late lactation. Second, a similar comparison between non-EBF mothers by stage of lactation also identified a higher differential abundance of Actinobacteria and Firmicutes species in early lactation, but only Proteobacteria and not Bacteroidetes in late lactation, indicating a further shift in the milk microbial ecosystem with fewer oral bacteria present in late lactation. Third, comparisons between EBF and non-EBF mothers at both early and late lactation showed that mothers who exclusively breastfed had more differentially abundant species in early (11 vs 1) and late (13 vs 2) lactation. Fourth, EBF at early and late lactation had more commensal and lactic acid bacteria, including Lactobacillus gasseri, Granulicatella elegans, Streptococcus mitis, and Streptococcus parasanguinis, compared to those who did not exclusively breastfeed. Collectively, these results show that EBF has more differentially abundant bacteria, including commensal and lactic acid bacteria, and that the addition of agüitas (herbal teas) and/or complementary foods modify the milk microbiome composition by reducing the oral bacteria and introducing more environmentally sourced bacteria to the ecosystem.

Infant Anthropometry and Growth Velocity Before 6 Months are Associated with Breastfeeding Practices and the Presence of Subclinical Mastitis and Maternal Intestinal Protozoa in Indigenous Communities in Guatemala

BACKGROUND

The possibility that maternal health status and breastfeeding practices contribute to growth faltering before 6 mo is underexplored.

OBJECTIVES

This longitudinal study investigated whether indicators of subclinical mastitis (SCM) and breast inflammation, maternal fecal-oral contamination, and/or breastfeeding practices were associated with infant anthropometry or growth velocity before 6 mo.

METHODS

Indigenous Mam-Mayan mother-infant dyads (n = 140) were recruited. Breast milk was collected at early (<6 wk) and established (4-6 mo) lactation when maternal and infant anthropometry were measured. Milk Na:K ratio as an indicator of SCM and concentrations of 4 proinflammatory cytokines were measured. Maternal stool samples were examined for the presence of intestinal parasites including nonpathogenic protozoa (Endolimax nana, Iodamoeba bütschlii, Entamoeba coli, Blastocystis hominis). Questionnaires characterized breastfeeding and hygiene practices. Multiple linear regression identified factors associated with infant growth attainment [weight-for-age z-score (WAZ), length-for-age z-score (LAZ), and head circumference-for-age z-score (HCAZ)] and growth velocity (expressed as change per day from early to established lactation). Multiple logistic regression identified factors associated with increased odds of underweight, stunting, and low head circumference at both lactation stages.

RESULTS

A higher Na:K ratio, individual nonpathogenic protozoa, and specific breastfeeding and hygiene practices were associated with impaired growth before 6 wk and at 4-6 mo in exclusively breastfed infants. Growth velocity for weight was inversely associated with Entamoeba coli but cranial growth was associated positively with Iodamoeba bütschlii whereas feeding colostrum in early lactation was protective and decreased the odds of an HCAZ < -2 SD. Finally, the presence of SCM in early lactation increased the likelihood of both WAZ < -2 SD and LAZ < -2 SD by 6 wk.

CONCLUSIONS

Prevention of SCM can improve early infant weight, but measures that promote the feeding of colostrum and reduce exposure to fecal-oral contamination might be required to minimize infant growth faltering in breastfed infants.

Fear, violence, inequality, and stunting in Guatemala

BACKGROUND

Stunting is defined by the public health community as a length- or height-for-age <-2 SD of a growth standard or reference and is claimed to be caused by poor nutrition, repeated infection, and inadequate psychosocial stimulation.

MATERIAL AND METHODS

Stunting is common at all income levels in middle- and low-income countries. At the higher income levels, stunting is unlikely to be caused by nutrient deficiency or infectious disease.

RESULTS

In Guatemala, 17% of <5-year-olds in the highest family income quintile are stunted. Guatemala has a history of violence from armed conflict, current-day social and economic inequalities, government corruption, and threat of kidnapping for the wealthiest families.

DISCUSSION AND CONCLUSION

The high level of persistent violence creates an ecology of fear, an extreme range of inequalities in Social-Economic-Political-Emotional resources, and biosocial stress that inhibits skeletal growth and causes stunting for people of all income levels.

Human Milk Microbiota in an Indigenous Population Is Associated with Maternal Factors, Stage of Lactation, and Breastfeeding Practices

BACKGROUND

Human milk contains a diverse community of bacteria that are modified by maternal factors, but whether these or other factors are similar in developing countries has not been explored. Our objective was to determine whether the milk microbiota was modified by maternal age, BMI, parity, lactation stage, subclinical mastitis (SCM), and breastfeeding practices in the first 6 mo of lactation in an indigenous population from Guatemala.

METHODS

For this cross-sectional study, Mam-Mayan indigenous mothers nursing infants aged <6 mo were recruited. Unilateral human milk samples were collected (n = 86) and processed for 16S rRNA sequencing at the genus level. Microbial diversity and relative abundance were compared with maternal factors [age, BMI, parity, stage of lactation, SCM, and 3 breastfeeding practices (exclusive, predominant, mixed)] obtained through questionnaires.

RESULTS

Streptococcus was the most abundant genus (33.8%), followed by Pseudomonas (18.7%) and Sphingobium (10.7%) but relative abundance was associated with maternal factors. First, Lactobacillus and Streptococcus were more abundant in early lactation whereas the common oral (Leptotrichia) and environmental (Comamonas) bacteria were more abundant in established lactation. Second, Streptococcus,Lactobacillus,Lactococcus,Leuconostoc, and Micrococcus had a higher abundance in multiparous mothers compared with primiparous mothers. Third, a more diverse microbiota characterized by a higher abundance of lactic acid bacteria (Lactobacillus,Leuconostoc, and Lactococcus), Leucobacter, and Micrococcus was found in mothers with a healthy BMI. Finally, distinct microbial communities differed by stage of lactation and by exclusive, predominant, or mixed breastfeeding practices.

CONCLUSION

Milk bacterial communities in an indigenous community were associated with maternal factors. Higher microbial diversity was supported by having a healthy BMI, the absence of SCM, and by breastfeeding. Interestingly, breastfeeding practices when assessed by lactation stage were associated with distinct microbiota profiles.

Distinct Changes Occur in the Human Breast Milk Microbiome Between Early and Established Lactation in Breastfeeding Guatemalan Mothers

Human breast milk contains a diverse community of bacteria, but as breast milk microbiome studies have largely focused on mothers from high income countries where few women breastfeed to 6 months, the temporal changes in the breast milk microbiome that occur during later lactation stages have not been explored. For this cross-sectional study, microbiota from breast milk samples of Mam-Mayan mothers living in eight remote rural communities in the Western Highlands of Guatemala were analyzed. All mothers delivered vaginally and breastfed their infants for 6 months. Breast milk from 76 unrelated mothers was used to compare two lactation stages, either “early” (6–46 days post-partum, n = 33) or “late” (109–184 days post-partum, n = 43). Breast milk microbial communities were assessed using 16S ribosomal RNA gene sequencing and lactation stages were compared using DESeq2 differential abundance analysis. A total of 1,505 OTUs were identified, including 287 which could be annotated as putative species. Among several maternal factors, lactation stage explained microbiome variance and inertia in ordination with the most significance (p < 0.001). Differential abundance analysis identified 137 OTUs as significantly higher in either early or late lactation. These included a general shift from Staphylococcus and Streptococcus species in early lactation to Sphingobium and Pseudomonas species in late lactation. Species enriched in early lactation included putative commensal bacteria known to colonize the infant oral and intestinal tracts whereas species enriched in late lactation had a uniform functional trait associated with aromatic compound degradation. Differentially abundant species also included several species which have not previously been reported within breast milk, such as Janthinobacterium agaricidamnosum, Novosphingobium clariflavum, Ottowia beijingensis, and Flavobacterium cucumis. These discoveries describe temporal changes to the breast milk microbiome of healthy Guatemalan mothers from early to late lactation. Collectively, these findings illustrate how studying under-represented human populations might advance our understanding of factors that modulate the human milk microbiome in low and middle income countries (LMIC).

What influences child feeding in the Northern Triangle? A mixed-methods systematic review

Optimising child feeding behaviours could improve child health in Guatemala, Honduras and El Salvador, where undernutrition rates remain high. However, the design of interventions to improve child feeding behaviours is limited by piecemeal, theoretically underdeveloped evidence on factors that may influence these behaviours. Between July 2018 and January 2020, we systematically searched Cochrane, Medline, EMBASE, Global Health and LILACS databases, grey literature websites and reference lists, for evidence of region-specific causes of child feeding behaviours and the effectiveness of related interventions and policies. The Behaviour Change Wheel was used as a framework to synthesise and map the resulting literature. We identified 2,905 records and included 68 relevant studies of mixed quality, published between 1964 and 2019. Most (n = 50) were quantitative, 15 were qualitative and three used mixed methods. A total of 39 studies described causes of child feeding behaviour; 29 evaluated interventions or policies. Frequently cited barriers to breastfeeding included mothers' beliefs and perceptions of colostrum and breast milk sufficiency; fears around child illness; and familial and societal pressures, particularly from paternal grandmothers. Child diets were influenced by similar beliefs and mothers' lack of money, time and control over household finances and decisions. Interventions (n = 22) primarily provided foods or supplements with education, resulting in mixed effects on breastfeeding and child diets. Policy evaluations (n = 7) showed positive and null effects on child feeding practices. We conclude that interventions should address context-specific barriers to optimal feeding behaviours, use behaviour change theory to apply appropriate techniques and evaluate impact using robust research methods.

Impacts of antenatal nursing interventions on mothers' breastfeeding self-efficacy: an experimental study

Background

A considerable amount of research demonstrates how breastfeeding self-efficacy significantly influences breastfeeding outcomes. The aim of this study was to evaluate the role of nursing intervention on mother’s breastfeeding self-efficacy.

Methods

In this experimental investigation, 130 pregnant women who attended a primary health care centre were randomly assigned to the experimental (n = 65) or control (n = 65) groups. The experimental group received two 60–90 min group breastfeeding educational sessions based on the breastfeeding self-efficacy theory along with routine care. Mothers’ knowledge, attitudes, prenatal and postnatal self-efficacy towards the breastfeeding were compared between both groups. The Iowa Infant Feeding Attitude Scale measured the attitudes. Prenatal Breastfeeding Self-Efficacy Scale measured the self-efficacy during pregnancy and Breastfeeding Self-Efficacy-Short Form measured the self-efficacy in postnatal period.

Results

Breastfeeding self-efficacy during pregnancy and following two months of delivery in the experimental group was significantly higher. The experimental group had a higher level of knowledge and attitude in comparison with subjects in the control group. In addition, the mothers who breastfed exclusively had higher levels of postnatal self-efficacy in both experimental and control groups compared to formula feeding women (52.00 vs. 39.45 in the control and 57.69 vs. 36.00 in the experimental subjects; P < 0.001).

Conclusion

The present investigation suggests that antenatal breastfeeding education is an effective way to increase the level of breastfeeding self-efficacy, which increases exclusive breastfeeding practice.

Anthropometry before Day 46 and Growth Velocity before 6 Months of Guatemalan Breastfed Infants Are Associated with Subclinical Mastitis and Milk Cytokines, Minerals, and Trace Elements

BACKGROUND

Subclinical mastitis (SCM) is an inflammatory condition of the mammary gland, but its association with human milk composition and infant growth is not well described.

OBJECTIVES

We investigated whether SCM, milk cytokines, and/or estimated intakes of milk minerals and trace elements were associated with infant anthropometry or growth velocity before 6 mo.

METHODS

Breast milk was collected from Mam-Mayan mothers (n = 114) at both early (2-46 d) and established (4-6 mo) lactation. Concentrations of 9 elements (sodium, potassium, calcium, magnesium, copper, iron, manganese, selenium, zinc) analyzed by inductively-coupled plasma mass spectrometry were used to estimate infants' daily intakes. Concentrations of 4 cytokines were measured. Milk concentrations and infants' estimated elemental intakes and anthropometric measurements during early and established lactation were compared by SCM status. Multiple regression was used to identify factors associated with infant growth attainment (<46 d) for infant weight- (WAZ), length- (LAZ), and head circumference-for-age (HCAZ) and weight-for-length (WLZ) z scores and with growth velocity (expressed as Δ/d) from early to established lactation.

RESULTS

SCM prevalence was higher in early (30%) than established (10%) lactation. Breast milk of SCM mothers had higher cytokine concentrations and higher magnesium in early and higher selenium concentrations in both early and established lactation (Padj < 0.0121). At day 46, regression models showed inverse associations of SCM with WLZ and IL-1β with LAZ (Padj < 0.0150). In contrast, linear growth velocity was positively associated with IL-1β measured in early lactation (Padj < 0.0124), whereas cranial growth velocity was positively associated with IL-8 measured during established lactation ( Padj < 0.0124).

CONCLUSIONS

Despite a high prevalence of inadequate intakes, only infants' intake of milk magnesium during early lactation was associated with linear growth velocity in breastfed infants <6 mo. Evidence shows that SCM, breast-milk cytokines, and infants' estimated intakes of select elements are independently associated with growth attainment and growth velocity during lactation.

Infant growth faltering linked to subclinical mastitis, maternal faecal-oral contamination, and breastfeeding

Infant growth faltering occurs in breastfed infants <6 months of age. The possibility that maternal health status contributes to this growth faltering is underexplored. We investigated whether (a) subclinical mastitis (SCM), an asymptomatic inflammation of the breast, (b) maternal intestinal nematode and protozoan infections, indicators of faecal-oral contamination, or (c) poor breastfeeding practices increased the odds of stunting (length-for-age z-score < -2SD), underweight (weight-for-age z-score < -2SD), or low head circumference (head circumference-for-age z-score < -2SD) in breastfed infants in rural indigenous communities in Guatemala. Mother-infant dyads (n = 105) were subdivided into those with and without SCM (milk Na:K ratio > 0.6). Maternal and infant anthropometry were measured at the time of breast milk collection. Maternal stool samples were examined for the presence of intestinal nematodes and protozoa. Questionnaires were used to characterize breastfeeding practices (exclusivity and frequency) and support, hygiene (latrine use and household faucet), and infant diarrhoea. SCM occurred in 14% of women and was associated with increased odds of infant stunting (odds ratio [OR] = 4.3; confidence interval [CI] [1.1, 15.8]), underweight (OR = 9.2; CI [1.8, 48.0]), and low head circumference (OR = 15.9; CI [2.6, 96.9]). Maternal pathogenic protozoa and nematodes were uncommon (<4%), but nonpathogenic protozoa were common (e.g., Entamoeba coli [39%]). Entamoeba coli increased the likelihood (OR = 3.3; CI [1.02, 10.6]) of low head circumference, whereas higher breastfeeding frequency lowered its odds (OR = 0.74, CI [0.56, 0.97]). Prevention of SCM may improve early infant growth, but public health measures that increase breastfeeding frequency and reduce faecal-oral contamination may be required to minimize low head circumference.

"Here we are part of a living culture": Understanding the cultural determinants of health in Aboriginal gathering places in Victoria, Australia

This article provides an exploration of the cultural determinants of health, based on a research evaluation investigating a number of Aboriginal gathering places in Victoria (Australia). Gathering places are recognised as settings in which people practice and learn about local Aboriginal culture, history and place. Academic literature on gathering places is sparse. Thirteen gathering places were evaluated in this research. Each site is unique and has a specific story that connects it to the history and geography of the place in which it is located. Sixty-nine gathering place members participated in qualitative semi-structured interviews or focus groups. Using thematic analysis, the findings were divided into four key themes associated with cultural determinants of health (social networks; inclusiveness; empowerment; connections). These elements create a safe place to learn about culture and Country, and support an environment for strengthening identity, improving health and building resilience. The findings from this study highlight the benefits of using gathering places to explore the cultural determinants of health.

Early Initiation of Breastfeeding Among Maya Mothers in the Western Highlands of Guatemala: Practices and Beliefs

BACKGROUND

Guatemala exhibits the sixth highest rate of child stunting worldwide, and stunting disproportionately affects Guatemala indigenous communities. In a country struggling to combat this result of malnutrition, early child nutrition is especially critical. Specifically, early initiation of breastfeeding is important for the development of newborn infants. Understanding beliefs and practices related to early initiation of breastfeeding in Maya Guatemala may provide an avenue to guide nutrition interventions in indigenous communities. Research aim: This study aimed to determine major beliefs and practices associated with early initiation of breastfeeding among Maya mothers in Lake Atitlán, Guatemala.

METHODS

As part of a larger study to assess child nutrition in the Lake Atitlán region, we created a series of semistructured interview questions to document breastfeeding practices and beliefs among mothers. We conducted and audio-recorded in-person interviews that were translated from Kaqchikel, the local language, to Spanish by a community assistant.

RESULTS

We conducted 178 interviews with mothers; 76% practiced early initiation. Early initiation was associated with the village and complementary feeding practices. Mothers held a variety of beliefs about the value of colostrum, and these beliefs were associated with the village. Mothers who held negative beliefs toward colostrum were more likely to delay breastfeeding initiation.

CONCLUSION

Although most Maya mothers practice early initiation, the intervillage disparity in breastfeeding practices demonstrates a need to geographically focus breastfeeding interventions. Our novel insights into the breastfeeding beliefs among Maya mothers will serve as a guide to structure culturally competent breastfeeding education interventions in indigenous communities.

Delayed breastfeeding initiation and infant survival: A systematic review and meta-analysis

Objective

To assess the existing evidence regarding breastfeeding initiation time and infant morbidity and mortality.

Study design

We conducted a systematic review and meta-analysis. We searched Pubmed, Embase, Web of Science, CINAHL, Popline, LILACS, AIM, and Index Medicus to identify existing evidence. We included observational studies and randomized control trials that examined the association between breastfeeding initiation time and mortality, morbidity, or nutrition outcomes from birth through 12 months of age in a population of infants who all initiated breastfeeding. Two reviewers independently extracted data from eligible studies using a standardized form. We pooled effect estimates using fixed-effects meta-analysis.

Results

We pooled five studies, including 136,047 infants, which examined the association between very early breastfeeding initiation and neonatal mortality. Compared to infants who initiated breastfeeding ≤1 hour after birth, infants who initiated breastfeeding 2–23 hours after birth had a 33% greater risk of neonatal mortality (95% CI: 13–56%, I² = 0%), and infants who initiated breastfeeding ≥24 hours after birth had a 2.19-fold greater risk of neonatal mortality (95% CI: 1.73–2.77, I² = 33%). Among the subgroup of infants exclusively breastfed in the neonatal period, those who initiated breastfeeding ≥24 hours after birth had an 85% greater risk of neonatal mortality compared to infants who initiated <24 hours after birth (95% CI: 29–167%, I² = 33%).

Conclusions

Policy frameworks and models to estimate newborn and infant survival, as well as health facility policies, should consider the potential independent effect of early breastfeeding initiation.

Minerals and Trace Elements in Human Breast Milk Are Associated with Guatemalan Infant Anthropometric Outcomes within the First 6 Months

BACKGROUND

Breast milk is the recommended source of nutrients for infant growth, but its adequacy to meet infants' mineral and trace element needs is unknown.

OBJECTIVES

We used breast-milk mineral and trace element concentrations of Guatemalan mothers at 3 lactation stages to estimate total daily intakes and to determine whether intakes were associated with early infant growth.

METHODS

In this cross-sectional study, breast-milk samples were collected from Mam-Mayan mothers during transitional (5-17 d, n = 56), early (18-46 d, n = 75), and established (4-6 mo, n = 103) lactation; z scores for weight (WAZ), length (LAZ), and head circumference (HCAZ) were measured. Concentrations of 11 minerals (calcium, potassium, magnesium, sodium, copper, iron, manganese, rubidium, selenium, strontium, and zinc) were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS). WHO equations were used to calculate the estimated energy requirement, which was divided by the energy density of breast milk to estimate daily milk volume, and this number was multiplied by breast-milk mineral concentrations to estimate intakes. Principal component analyses identified clusters of minerals; principal components (PCs) were used in regression analyses for anthropometric outcomes.

RESULTS

Estimated breast-milk intakes during established lactation were insufficient to compensate for the lower milk sodium, copper, manganese, and zinc concentrations in male infants and the lower sodium, iron and manganese concentrations in female infants. Estimated intakes of calcium, magnesium, potassium, sodium, and selenium were below the Institute of Medicine Adequate Intake for both sexes at all 3 stages of lactation. In early lactation, multiple linear regressions showed that PC1 (calcium, magnesium, potassium, rubidium, and strontium intakes) was positively associated with WAZ, LAZ, and HCAZ. In established lactation, the same PC with sodium added was positively associated with all 3 anthropometric outcomes; a second PC (PC2: zinc, copper, and selenium intakes) was associated with WAZ and LAZ but not HCAZ.

CONCLUSIONS

Breast milk may be inadequate in selected minerals and trace elements where higher estimated intakes were associated with greater infant growth.

Quantitative Methodologies Reveal a Diversity of Nutrition, Infection/Illness, and Psychosocial Stressors During Pregnancy and Lactation in Rural Mam-Mayan Mother–Infant Dyads From the Western Highlands of Guatemala

Background:

The nature and severity of 3 categories of maternal stressors (nutritional, infectious, and psychosocial) that may impact maternal health and early infant growth are not often considered together.

Objectives:

To describe quantitative methodologies; assess construct validity of questionnaires; report variability in sociodemographic, obstetric, nutritional, infectious, and psychosocial characteristics; and compare characteristics between pregnancy and lactation and between study cohorts of Mam-Mayan mother–infant dyads.

Methods:

Grounded in participatory action research and a socioecological framework, this observational study enrolled a longitudinal cohort of 155 women, followed during pregnancy (6-9 months), early (0-6 weeks), and later (4-6 months) postpartum, and 2 cross-sectional cohorts (60 early and 56 later postpartum). Household and social factors; obstetric history; nutritional, infectious, and psychosocial stressors; and infant characteristics were explored.

Results:

Diet diversity (3.4 ± 1.3) and adult food security (38%) were low. Urinary and gastrointestinal infections were rare (<5%), whereas experience of local idioms of distress was frequent (20%-50%). Participants reported low maternal autonomy (81%), high paternal support (70%), small social support networks (2.7 ± 1.3 individuals), and high trust in family (88%) and community-based institutions (61%-65%) but low trust in government services (6%). Domestic violence was commonly reported (22%). Infant stunting was common (36% early postpartum and 43% later postpartum) despite frequent antenatal care visits (7.5 ± 3.8). Participant engagement with the research team did not influence study outcomes based on comparisons between longitudinal and cross-sectional cohorts.

Conclusions:

The variability in sociodemographic, nutritional, and psychosocial variables, will allow exploration of factors that promote resilience or increase vulnerability of the mother–infant dyad.