Correlations between Maternal, Breast Milk, and Infant Vitamin B12 Concentrations among Mother-Infant Dyads in Vancouver, Canada and Prey Veng, Cambodia: An Exploratory Analysis

Correlations between serum vitamin B12 and folate levels among mother-infant dyads in Punjab state, North-West India

AIM

Adequate vitamin B12 levels in infancy are crucial for normal psychomotor and cognitive development of infants. Our aim was to examine serum vitamin B12, folate and ferritin levels in exclusively breastfed healthy full-term infants (age group: 1-6 months), and also investigate their correlation with maternal markers.

METHODS

A cross-sectional study was conducted on 100 exclusively breastfed healthy full-term infants (age group: 1-6 months) along with their lactating mothers. Serum vitamin B12, folate and ferritin levels were determined for each mother-infant dyad using enzyme-linked immunosorbent assay.

RESULTS

The mean serum vitamin B12, folate and ferritin levels were 512 vs. 535 pg/mL, 15 vs. 12 ng/mL and 313 vs. 114 ng/mL in infants and mothers, respectively. Among 100 infants, 26 (26%) had lower vitamin B12 levels and 5 (5%) had inadequate folate levels. In addition, 22 (22%) of 100 lactating mothers were deficient in vitamin B12 levels and 14 (14%) had inadequate folate levels. We found a statistically significant positive correlation between infant and maternal vitamin B12 (r = 0.659, P < 0.001) and folate levels (r = 0.51, P < 0.001).

CONCLUSION

Vitamin B12 deficiency was observed in 26% of infants and 22% of lactating mothers. Vitamin B12 and folate levels of infants were positively correlated with maternal levels in the state of Punjab, North-West India. Our findings support that maternal vitamin B12 status can be used as a valuable predictor of infant vitamin B12 status.

Intake of Vitamin B12 and Folate and Biomarkers of Nutrient Status of Women within Two Years Postpartum

Background: Little is known about variation in vitamin B12 and folate status among Chinese women 2 years postpartum. This study assessed intake of vitamin B12 and folate and biomarkers of nutrient status among Chinese women postpartum. Methods: Demographic information, multi-/single-nutrient supplementation, dietary data, serum vitamin B12 and serum folate were assessed in 982 women within 2 years postpartum, using ten investigation sites in Zhejiang Province from the National Nutritional Study 2016−2017, which is a nationally representative cross-sectional study, to form a representative provincial sample of Zhejiang Province. The dietary diversity score (DDS) was used for assessing the dietary pattern. Results: Vitamin B12 increased slightly at the early stage of postpartum and then dropped over time. Serum folate level elevated with postpartum time. The median serum vitamin B12 concentration was 494.59 (373.21−650.20) pg/mL, and folate was 7.58 (5.02−10.34) ng/mL. Correspondingly, vitamin B12 levels suggesting marginal deficiency (200−300 pg/mL) and deficiency (<200 pg/mL) resulted as 9.27% and 3.26%, respectively, and folate level suggesting deficiency (<3 ng/mL) was 9.16%. Multi-/single-nutrient supplementation during pregnancy was associated with log-transformed serum vitamin B12 and folate level after adjusting for potential confounders (vitamin B12: ß (SE) = 0.124 (0.028), p < 0.001; folate: 0.128 (0.035), <0.001). Additionally, postpartum nutrient supplementation was associated with log-transformed serum folate level, especially for lactating women (ß (SE) = 0.204 (0.062), p = 0.001). Increased DDS was significantly associated with elevated serum vitamin B12 and folate levels (vitamin B12: ß (SE) = 0.028 (0.011), p = 0.011; folate: 0.030 (0.014), 0.031). In addition, age and educational level were influencing factors for serum vitamin B12 and folate concentrations among postpartum women. Conclusion: Serum vitamin B12 level decreased and folate level increased with postpartum age among Chinese women. Nutrient supplementation during pregnancy was related to elevated serum vitamin B12 and folate concentrations. Postpartum nutrient supplementation was associated with the increased serum folate level of lactating women. Dietary diversity was related to increased serum vitamin B12 and folate levels, especially among postpartum women with younger age and lower educational level.

Analysis of food sources and nutrient intakes of selected breastfeeding mothers in Metro Manila, Philippines

BACKGROUND

This study evaluated the food and nutrient intakes of selected breastfeeding mothers and identified the top food sources of nutrient intakes.

METHODS

This is a cross-sectional, non-interventional study conducted in one of the private medical centers in Metro Manila, Philippines.

PARTICIPANTS

The sample size included 70 mothers of healthy, term, exclusively breastfed infants aged 21-26 days at enrollment. Mothers were scheduled to visit the clinic at days 1, 22, 57, and day 90.Similarly, food diaries were obtained during these periods with a 3-day food record per clinic visit totaling to 12 records per mother at the end of 90 days. At every clinic visit, the records were validated face - to - face by the registered nutritionist - dietitians. An extension of the mother's participation until day 155 was implemented for the collection of clinical outcomes used by Pediatricians. Mean food intakes were calculated. A PC-Software for Intake Distribution Estimation (PC-SIDE) program was used in the estimation of inadequate intakes. Socio-economic status was collected using standard questionnaires. Weight and height were measured using standard techniques to compute for BMI.

RESULTS

Anthropometric results for the breastfeeding mothers reported a mean weight of 56.9 kg (SE = 1.3) and a mean height of 152.4 cm (SE = 0.6). In terms of body mass index (BMI), 8.6% were chronic energy deficient, and 34.3% were overweight while 12.9% were obese. Mean energy intake of breastfeeding mothers was 2516.7 kcal/day, which was 28.6% higher than the EER of 1957 kcal/day. Mean protein intake was 78.4 g/day, which was 37% inadequate while fat intake as percentage of total energy was excessive by 4%. Nutrient inadequacy is high for almost all nutrients: iron (99%), folate (96%), riboflavin (39%), vitamin B6 (63%), vitamin B12 (46%) and thiamine (22%). The top 5-food sources with highest percent contribution to energy are rice (43.1%), bread (8.1%), pork (7.7%), powdered milk (5.9%), and sweet bakery products (5%).

CONCLUSIONS

There is a high prevalence of protein and micronutrient inadequacies in the diet of breastfeeding mothers. The prevalence of overweight and obesity is high among breastfeeding mothers. These findings might be explained by the low variety and nutrient-poor foods consumed by the breastfeeding mothers. Understanding the major food sources of nutrient intake of breastfeeding mothers could be used to intensify if not craft interventions to address the nutrient gaps. Improving the maternal nutrition may contribute to having quality breastmilk to infants.

Association of Maternal Vitamin B12 Status With Infant Findings and Neurodevelopment in Vitamin B12-Deficient Breast-fed Babies

Few studies have examined the association between maternal vitamin B12 status and their breast-fed infants' findings. The objective of this study was to analyze the association of maternal B12 status with infant findings including neurodevelopmental outcome in breast-fed babies with B12 deficiency. Correlation analyses between the laboratory findings of infants with B12 deficiency (n=120) and their mothers were performed and the association of maternal B12 status with infant findings including the Denver-II developmental screening test (DDST II) results was examined. There was a significant correlation between infant and maternal B12 levels (r=0.222; P=0.030), and between infant and maternal homocysteine (Hcy) levels (r=0.390; P<0.001). Among the babies 4 months of age or older, maternal Hcy levels were significantly correlated with infant mean corpuscular hemoglobin (r=0.404; P=0.001) and infant mean corpuscular volume (r=0.461; P<0.001). Mothers of infants with abnormal DDST II had lower vitamin B12 (196.9±41.2 vs. 247.0±77.0 pg/mL; P=0.018) and higher Hcy levels (17.3±5.0 vs. 10.7±3.1 µmol/L; P<0.001) than mothers of infants with normal DDST II. A lower maternal vitamin B12 status may be related to impaired neurodevelopment in breast-fed infants with vitamin B12 deficiency. Pregnant and lactating women should be offered easy access to healthy nutrition and vitamin B12 supplements.

Vitamin B12 quantification in human milk - Beyond current limitations using liquid chromatography and inductively coupled plasma - Mass spectrometry

Vitamin B12 plays a key role in human biological functions and is vital in the neurological development of infants. The assessment of the vitamin B12 intake in exclusively breastfed babies depends on the reliability of its determination in milk. In this report, we present a new accurate and robust method for quantification of vitamin B12 in human milk. A highly specific sample preparation is applied, associated with chromatographic separation and detection by ICP-MS. Excellent sensitivity and accuracy are reported, with recovery values well within acceptability limits (80-120%), within- and between-day variability are lower than 10% and 15% respectively. Strong correlation with a microbiological assay was observed (r² = 0.9) within the validation range (40-1000 pmol/L, corresponding to 54 to 1355 ng/L). The method can be used to routinely monitor vitamin B12 in clinical or population observational studies, determine infant's intake or assess efficacy of mother's supplementation.

Does vegan diet influence umbilical cord vitamin B12, folate, and ferritin levels?

PURPOSE

To determine the influence of maternal diets on maternal and umbilical cord blood levels of vitamin B12, folic acid, ferritin, and hemoglobin.

METHODS

A prospective observational study on women who maintained the same diet for at least 3 months prior to, and throughout current pregnancy. Women were divided according to their diet. Diet questionnaires were filled in during the 3rd trimester. Blood samples for complete blood counts and levels of ferritin, vitamin B12, folate, and albumin were taken from the women prior to delivery and from the umbilical cord immediately after delivery.

RESULTS

The 273 enrolled women included 112 omnivores, 37 pescatarians, 64 vegetarians, and 60 vegans. There were no significant differences in the maternal B12 levels between the study groups (P = 0.426). Vegans had lower maternal ferritin levels compared to pescatarians (27 ± 17 vs 60 ± 74 ng/ml, respectively, P = 0.034), but not compared to vegetarians (P = 0.597), or omnivores (P = 1.000). There were no significant differences in the umbilical cord B12, folate, ferritin, and hemoglobin levels between the study groups. A sub-analysis that compared women who consumed multivitamins, B12 and iron supplements during pregnancy to women who did not, revealed differences in the levels of umbilical-cord B12 (1002 ± 608 vs 442 ± 151 pg/ml, respectively, P = 0.000) and maternal blood B12 (388 ± 209 vs 219 ± 95 pg/ml, respectively, P = 0.030) only among vegans, but not among omnivores.

CONCLUSION

Vegan diet does not change the umbilical cord levels of B12, folic acid, ferritin, and hemoglobin. Vegans who do not take any vitamin supplementation are at greater risk for B12 deficiency than omnivores.

Macro- and Micronutrients in Milk from Healthy Cambodian Mothers: Status and Interrelations

BACKGROUND

Except for low thiamin content, little is known about vitamins or macronutrients in milk from Cambodian mothers, and associations among milk nutrients.

OBJECTIVES

We measured fat-soluble vitamins (FSVs) and water-soluble vitamins (WSVs), and macronutrients, and explored internutrient associations in milk from Cambodian mothers.

METHODS

Milk from women (aged 18-45 y, 3-27 wk postpartum, n = 68) who participated in a thiamin-fortification trial were analyzed for vitamins B-2 (riboflavin, FAD), B-3 (nicotinamide), B-5, B-6 (pyridoxal, pyridoxine), B-7, B-12, A, E [α-tocopherol and γ-tocopherol (γ-TPH)], carotenoids, carbohydrate (CHO), fat, and protein. Milk vitamin B-1 [thiamin, thiamin monophosphate (TMP), thiamin pyrophosphate (TPP)] was previously assessed for fortification effects. Milk nutrient concentrations were compared with the Adequate Intake (AI) values for infants aged 0-6 mo. Pearson correlation was used to examine internutrient associations after excluding nutrients affected by fortification.

RESULTS

Fortification increased thiamin and B-1 and decreased γ-TPH. Less than 40% of milk samples met the AIs for all vitamins, and 10 samples did not reach any AI values for the analyzed nutrients. CHO, fat, and energy values were met in 1.5-11.8%, and protein in 48.5%, of the samples. Whereas fat, protein, and energy were related (all r < 0.5; P < 0.001) and associated with FSVs and WSVs, CHO correlated only with some WSVs. TPP was not correlated with B-1 vitamers, but with other WSVs (r = 0.28-0.58; P < 0.019). All FSVs, except α-carotene, were correlated with each other (r = 0.42-0.98; P < 0.002). TPP, FAD, B-2, and B-3 were associated with almost all FSVs (r = 0.24-0.63; P < 0.044).

CONCLUSIONS

Cambodian women might not provide sufficient nutrients to their exclusively breastfeeding infants. Besides thiamin, all other vitamins measured were much lower than the AI. There were many strong correlations among macronutrients and vitamins; the extent to which these are explained by maternal diet, milk volume, maternal physiology, or genetics requires additional exploration.

Vitamin B12 is Low in Milk of Early Postpartum Women in Urban Tanzania, and was not Significantly Increased by High dose Supplementation

The effect of maternal multivitamin supplementation on breast milk vitamin B12 concentrations has not been examined in Tanzania, where the prevalence of maternal plasma B12 insufficiency is 25.6%. Multivitamins (containing 50 µg vitamin B12) or placebo were provided during pregnancy and in the postpartum period. Breast milk samples were collected at or around six weeks postpartum from 491 participants in a trial of multivitamins (NCT00197548). Linear and logistic regression models were used to examine the effect of supplements on vitamin B12 concentration in milk and its associations with other variables including potential confounders. Median vitamin B12 concentration in breast milk was 206 pmol/L and 70% of women had levels indicating inadequacy (<310 pmol/L). Multivitamin supplements did not significantly reduce the odds of inadequate vitamin B12 in breast milk, suggesting suboptimal absorption. A single unit increase in maternal hemoglobin at six weeks was associated with 18% lower odds of inadequate vitamin B12 in breast milk. Participants with higher BMI at baseline had double the odds of having inadequate vitamin B12 than the reference group (<22 kg/m2). Trials to determine the optimal dose, route, and duration of supplementation to improve maternal B12 status in Sub-Saharan Africa are of utmost importance.

Breast milk vitamin B12 concentration and incidence of diarrhea and respiratory infections among infants in urban Tanzania: a prospective cohort study

Objective

A recent trial of vitamin B12 supplementation among Indian children 6–30 months found no effect on the incidence of diarrhea and respiratory infections. These results differ with studies in adults that showed improvement of the immune response following treatment with vitamin B12. We sought to determine how the adequacy of vitamin B12 concentrations in breast milk could act as immune modulator and protect against the incidence of diarrhea and respiratory infections of children up to 18 months in urban Tanzania.

Results

A prospective cohort study was undertaken to determine the association of breast milk vitamin B12 concentration with the incidence of acute respiratory infection and diarrhea among infants in urban Tanzania. A random sample of 491 women enrolled in a trial of multivitamins provided milk for B12 analysis at or around 6 weeks postpartum. Of 491 women, 345 had breast milk vitamin B12 inadequacy (< 310 pmol/L). Using generalized estimating equations, we found no overall association of milk vitamin B12 concentration with incident diarrhea and acute respiratory infections in infants. Studies measuring longitudinal changes of breast milk B12 concentration over time are needed to clarify the role of breast milk vitamin B12 in childhood infections.

Vitamin B12 concentrations in milk from Norwegian women during the six first months of lactation

BACKGROUND

Human milk vitamin B12 (B12) concentrations depend on maternal status and intake; only few data are available in high-income countries.

OBJECTIVE

We assessed human milk B12 concentrations during the first 6 months postpartum in Norwegian women and its association with maternal dietary B12 intake and maternal urinary methylmalonic acid (MMA) concentration.

METHODS

In this cross-sectional study, 175 mothers, exclusively (80%) or partially (20%) breastfeeding, were included. Milk B12 was measured by IMMULITE^®/IMMULITE^® 1000 B12 competitive protein binding assay and urinary MMA relative to creatinine (MMA/Cr) by liquid chromatography-tandem-mass spectrometry. Maternal habitual B12 intake and supplement use were estimated using a food frequency questionnaire.

RESULTS

Mean human milk B12 concentration was 327 pmol/L (range 140-1089), with 402 pmol/L at 1 month (n = 21), 333 pmol/L at four months (n = 32), and 299 pmol/L at 6 months (n = 21). Maternal B12 intake was 5 µg/d, 89% met the Estimated Average Requirement, and supplement use did not affect milk B12 concentrations. MMA/Cr was low in all women compared with published data. In exclusively breastfeeding women, MMA/Cr (beta (95% CI) -42.5 (-82.5, -2.5) and time since birth (-4.9 (-9.6, -0.3)) were significant predictors of human milk B12 concentrations. There was no association between total B12 intake and milk B12 concentration or between total B12 intake and MMA/Cr.

CONCLUSIONS

Maternal B12 status and human milk B12 concentrations are likely sufficient, based on adequate maternal B12 dietary intake combined with low urinary MMA concentrations. Nevertheless, milk B12 concentration fell during 6 months postpartum while maternal B12 status did not change.

Micronutrient-fortified infant cereal improves Hb status and reduces iron-deficiency anaemia in Indian infants: an effectiveness study

Anaemia affects approximately 69 % of Indian children aged 6–12 months, with Fe deficiency (ID) being a common cause. The effectiveness of micronutrient-fortified infant cereal in improving Fe status and neurodevelopment was evaluated in non-anaemic and mildly anaemic Indian infants. An intervention group (IC) enrolled at age 6 months consumed 50 g/d of rice-based cereal providing 3·75 mg Fe/d as ferrous fumarate for 6 months (n 80) and was compared with a matched static cross-sectional control group (CG) without intervention enrolled at age 12 months (n 80). Mean Hb was higher in IC (118·1 (sd 10·2) g/l) v. CG (109·5 (sd 16·4) g/l) at age 12 months (adjusted mean difference: 9·7 g/l; 95 % CI 5·1, 14·3; P < 0·001), while geometric mean serum ferritin tended to be higher (27·0 (–1 sd 13·4, +1 sd 54·4) v. 20·3 (–1 sd 7·5, +1 sd 55·0) ng/ml); P = 0·085) and soluble transferrin receptor was lower (1·70 (–1 sd 1·19, +1 sd 2·43) v. 2·07 (–1 sd 1·29, +1 sd 3·33) mg/l; P = 0·014). Anaemia (23 v. 45 %; P = 0·007) and ID (17 v. 40 %; P = 0·003) were lower in IC v. CG. Bayley Scales of Infant and Toddler Development Third Edition scores for language (P = 0·003), motor development (P = 0·018), social-emotional (P = 0·004) and adaptive behaviour (P < 0·001), but not cognitive development (P = 0·980), were higher in IC v. CG. No significant difference in anthropometric Z-scores was observed between the groups. Consuming a micronutrient-fortified infant cereal daily for 6 months during complementary feeding promoted better Fe status while reducing the risk for anaemia and ID and was associated with superior neurodevelopmental scores.

The Effects of Vegetarian and Vegan Diet during Pregnancy on the Health of Mothers and Offspring

Vegetarian and vegan diets have increased worldwide in the last decades, according to the knowledge that they might prevent coronary heart disease, cancer, and type 2 diabetes. Althought plant-based diets are at risk of nutritional deficiencies such as proteins, iron, vitamin D, calcium, iodine, omega-3, and vitamin B12, the available evidence shows that well planned vegetarian and vegan diets may be considered safe during pregnancy and lactation, but they require a strong awareness for a balanced intake of key nutrients. A review of the scientific literature in this field was performed, focusing specifically on observational studies in humans, in order to investigate protective effects elicited by maternal diets enriched in plant-derived foods and possible unfavorable outcomes related to micronutrients deficiencies and their impact on fetal development. A design of pregestational nutrition intervention is required in order to avoid maternal undernutrition and consequent impaired fetal growth.

Vitamin B12 Status in Pregnant Adolescents and Their Infants

Vitamin B₁₂ deficiency has been associated with increased risk of adverse pregnancy outcomes. Few prospective studies have investigated the burden or determinants of vitamin B₁₂ deficiency early in life, particularly among pregnant adolescents and their children. The objectives of this study were to determine the prevalence of vitamin B₁₂ deficiency and to examine associations between maternal and neonatal vitamin B₁₂ status in a cohort study of healthy pregnant adolescents. Serum vitamin B₁₂ and folate concentrations were measured in adolescents at mid-gestation (n = 124; 26.4 ± 3.5 weeks) and delivery (n = 131; 40.0 ± 1.3 weeks), and in neonates at birth using cord blood. Linear regression was used to examine associations between maternal and neonatal vitamin B₁₂ status. Although the prevalence of vitamin B₁₂ deficiency (<148.0 pmol/L; 1.6%) in adolescents was low during pregnancy, 22.6% of adolescents were vitamin B₁₂ insufficient (<221.0 pmol/L; 22.6%) at mid-gestation. Maternal vitamin B₁₂ concentrations significantly decreased from mid-gestation to delivery (p < 0.0001), and 53.4% had insufficient vitamin B₁₂ status at delivery. Maternal vitamin B₁₂ concentrations (p < 0.001) and vitamin B₁₂ deficiency (p = 0.002) at delivery were significantly associated with infant vitamin B₁₂ concentrations in multivariate analyses, adjusting for gestational age, maternal age, parity, smoking status, relationship status, prenatal supplement use, pre-pregnancy body mass index, race, and intake of vitamin B₁₂ and folate. Maternal vitamin B₁₂ concentrations significantly decreased during pregnancy and predicted neonatal vitamin B₁₂ status in a cohort of healthy pregnant adolescents.

Vitamin B-12 content in breast milk of vegan, vegetarian, and nonvegetarian lactating women in the United States

Background

The nutritional profile of human milk varies significantly between women, and the impact of maternal diet on these variations is not well understood.

Objective

We analyzed breast-milk vitamin B-12 concentration and vitamin B-12 supplement use pattern among women who adhered to different dietary patterns: vegan, vegetarian, and nonvegetarian.

Design

A total of 74 milk samples, 26 from vegan, 22 from vegetarian, and 26 from nonvegetarian breastfeeding mothers, were analyzed.

Results

The prevalences of low vitamin B-12 (<310 pmol/L) were 19.2% for vegans, 18.2% for vegetarians, and 15.4% for nonvegetarians, which was not significant by diet group (P = 1.00). The median (quartile 1, quartile 3) vitamin B-12 values were 558 pmol/L (331, 759 pmol/L) for vegans, 509 pmol/L (368, 765 pmol/L) for vegetarians, and 444 pmol/L (355, 777 pmol/L) for nonvegetarians (P = 0.890). The use of individual vitamin B-12 supplements was higher in vegans (46.2%) than in vegetarians (27.3%) and nonvegetarians (3.9%) (P = 0.001). In linear regression analysis, the use of individual vitamin B-12 supplements was a significant positive predictor of milk vitamin B-12 concentration (β ± SE: 172.9 ± 75.2; standardized β = 0.263; P = 0.024; R2 = 0.069), the use of a multivitamin had a significant negative relation with milk vitamin B-12 concentrations (β ± SE -222.0 ± 98.7; standardized β = -0.258; P = 0.028, R2 = 0.067;), whereas the use of a B-complex vitamin and prenatal vitamin were not predictive of vitamin B-12 milk concentration (P > 0.05).

Conclusions

Almost 20% of our study participants were classified as having low breast-milk vitamin B-12 concentrations (<310 pmol/L), independent of maternal diet pattern. Approximately 85% of participants categorized as having low vitamin B-12 were taking vitamin B-12 supplements at doses in excess of the Recommended Dietary Allowance, which suggests that more research is needed to determine breast-milk adequacy values.

Vitamin B-12 in Human Milk: A Systematic Review

Despite the critical role of vitamin B-12 in infant development, existing recommendations for infant and maternal intake during lactation are based on milk vitamin B-12 concentrations analyzed with outdated methods in a sample of 9 Brazilian women. Accurate quantification of vitamin B-12 in the milk matrix requires effective hydrolysis of the vitamin from haptocorrin, its binding protein. The objective of the present systematic review is to consider and critique evidence of associations between milk vitamin B-12 concentration and time postpartum, maternal vitamin B-12 consumption, maternal vitamin B-12 status, and sample collection methodology. A systematic search of published literature was undertaken using the US National Library of Medicine's MEDLINE/PubMed bibliographic search engine. Observational and intervention studies were included if research was original and vitamin B-12 concentration in human milk was measured using an appropriate method during the first 12 mo of lactation. Eleven studies met inclusion criteria. Vitamin B-12 concentration was highest in colostrum and decreased in a poorly delineated trajectory over the first 3-4 mo of lactation. There was some evidence of a positive association between habitual maternal vitamin B-12 intake and milk vitamin B-12 concentration in marginally nourished women. Supplementation with 50-250 µg vitamin B-12/d during pregnancy and lactation raised human milk vitamin B-12 concentrations while intervention was ongoing, whereas supplementation with 2.6-8.6 µg/d was effective in a population with poor baseline vitamin B-12 status but not in other populations. Whether milk vitamin B-12 concentration varies with maternal circulating vitamin B-12 concentrations or sampling methodology requires further research as existing data are conflicting. Additional research is needed to bridge knowledge gaps in the understanding of human milk vitamin B-12 concentrations. Reference values for vitamin B-12 in human milk and recommended intakes during infancy and lactation should be reevaluated using modern methods of analysis.

Maternal Serum Cobalamin at 18 Weeks of Pregnancy Predicts Infant Cobalamin Status at 6 Months-A Prospective, Observational Study

Background

An adequate maternal cobalamin status is crucial for fetal and infant neurodevelopment. Pregnancy-induced physiologic changes make evaluation of maternal cobalamin status in pregnancy difficult.

Objective

We have investigated maternal cobalamin status during pregnancy in order to establish a maternal cobalamin concentration which secures an optimal infant cobalamin status during the first 6 mo of life.

Methods

In an observational, prospective study, markers of cobalamin status including serum cobalamin, plasma total homocysteine (tHcy), and plasma methylmalonic acid (MMA) were assessed in healthy pregnant women (n = 114) from week 18 of pregnancy through 6 mo postpartum and related to infant cobalamin status at 6 mo. Healthy, never-pregnant women aged 18-40 y (n = 123) were included as controls.

Results

Compared to controls, all markers of cobalamin status were lower in pregnant women. Median serum cobalamin concentration progressively decreased from week 18 to week 36 of pregnancy (356 to 302 pmol/L, P < 0.001) and increased by >40% by 6 wk postpartum (518 pmol/L). The metabolic markers increased from week 18 of pregnancy to 6 wk postpartum: median plasma tHcy 3.9 to 7.7 μmol/L (P < 0.001), and MMA 0.13 to 0.17 μmol/L (P < 0.001). The serum cobalamin concentration of infants at age 6 mo correlated with maternal serum cobalamin concentration during pregnancy and postpartum (rho = 0.36-0.55, P < 0.001). A maternal serum cobalamin concentration <394 pmol/L during week 18 of pregnancy was associated with an increased risk (OR: 4.2; 95% CI: 1.5, 11.5) of infant biochemical cobalamin deficiency at 6 mo (defined as tHcy ≥6.5 μmol/L).

Conclusions

The maternal serum cobalamin concentration in early pregnancy is a strong predictor for later maternal and infant cobalamin status. To secure an optimal infant cobalamin status during the first 6 mo of life, we recommend a maternal serum cobalamin concentration >394 pmol/L at week 18 of pregnancy. This should be confirmed in an intervention study. This trial was registered at clinicaltrials.gov as NCT03272022.

Infant Serum and Maternal Milk Vitamin B-12 Are Positively Correlated in Kenyan Infant-Mother Dyads at 1-6 Months Postpartum, Irrespective of Infant Feeding Practice

Background

Vitamin B-12 is an essential nutrient required for many functions including DNA synthesis, erythropoiesis, and brain development. If maternal milk vitamin B-12 concentrations are low, infants may face elevated risks of deficiency when exclusively breastfed.

Objective

We evaluated cross-sectional associations between infant serum vitamin B-12 concentrations and maternal milk vitamin B-12 concentrations at 1-6 mo postpartum among an unsupplemented population in rural western Kenya, and assessed biological demographic, and dietary characteristics associated with adequate infant serum vitamin B-12.

Methods

We modeled 1) infant serum vitamin B-12 using maternal milk vitamin B-12 concentration with linear regression; and 2) adequate (>220 pmol/L) infant serum vitamin B-12 using hypothesized biological, demographic, and dietary predictors with logistic regression. In both models, we used generalized estimating equations to account for correlated observations at the cluster-level.

Results

The median (quartile 1, quartile 3) infant serum vitamin B-12 concentration was 276 pmol/L (193, 399 pmol/L) and approximately one-third of infants had serum vitamin B-12 ≤220 pmol/L, indicating that they were vitamin B-12 depleted or deficient. There was a positive correlation between maternal milk and infant serum vitamin B-12 (r = 0.36, P < 0.001) and in multivariable analyses, maternal milk vitamin B-12 concentration was significantly associated with infant serum vitamin B-12 adequacy (P-trend = 0.03).

Conclusions

Despite a high prevalence (90%) of maternal milk vitamin B-12 concentrations below the level used to establish the Adequate Intake (<310 pmol/L), there was a low prevalence of infant vitamin B-12 deficiency. We found few factors that were associated with infant vitamin B-12 adequacy in this population, including infant feeding practices, although maternal vitamin B-12 status was not measured. The contribution of maternal milk to infant vitamin B-12 status remains important to quantify across populations, given that maternal milk vitamin B-12 concentration is modifiable with supplementation. This trial was registered at clinicaltrials.gov as NCT01704105.