Vitamin A and the nursing mother-infant dyad: evidence for intervention

Vitamin A-fortified rice increases total body vitamin A stores in lactating Thai women measured by retinol isotope dilution: a double-blind, randomized, controlled trial

BACKGROUND

Lactating women are at increased risk for vitamin A (VA) deficiency due to demands for breast milk content and limited hepatic stores for women in some countries. Previously, consumption of triple-fortified rice, which included VA, iron, and zinc, successfully improved the VA status of Thai children in whom their total body VA stores (TBSs) were doubled in 2 mo.

OBJECTIVE

This study assessed the efficacy of consuming VA-fortified rice, which delivered 500 µg retinol activity equivalents (RAEs)/d, on TBSs and estimated total liver VA reserves (TLRs) in Thai lactating women using the retinol isotope dilution (RID) test.

METHODS

A randomized controlled trial was conducted with 70 lactating women (n = 35/group) who received either VA-fortified rice (500 µg RAEs/d) or unfortified rice for 14 wk on weekdays only. Serum retinol concentrations (SRs), C-reactive protein, and TBSs were assessed before and after the intervention. The paired 13C-RID test was used to measure TBSs. After a baseline blood sample, 2.0 µmol [14,15]-13C2-retinyl acetate was administered orally. A follow-up blood sample was drawn 14 d later. The RID test was repeated after the intervention.

RESULTS

TBSs increased significantly (P < 0.05) in the intervention group from 240 (182, 316) to 331 (251, 447) [geometric means (95% CIs)] µmol retinol, and this change in TBSs was significantly higher (P < 0.05) than that in the control group [+52.9 (-74, 453) compared with -4.3 (-106, 275) µmol retinol]. Estimated TLRs indicated a high prevalence of VA deficiency among these lactating women. Initial and final SRs did not differ by group and did not change over the course of the intervention.

CONCLUSION

VA-fortified rice improved the VA status of lactating women by increasing TBSs. A targeted approach to disseminate VA interventions among vulnerable groups should be considered in some contexts. This trial was registered at clinicaltrials.gov as NCT03056625.

Nutritional, inflammatory, and ecological correlates of maternal retinol allocation to breast milk in agro-pastoral Ariaal communities of northern Kenya

OBJECTIVES

Vitamin A (VA) is an essential micronutrient required for a range of biological functions throughout life. VA deficiency (VAD) claims an estimated 1 million preschool children's lives annually. Human milk is enriched with VA (retinol) from the maternal blood, which originates from the hepatic reserve and dietary intake. Secreting retinol into milk will benefit the nursing infant through breast milk, but retaining retinol is also important for the maternal health. Previous studies found that the public health intervention of high-dose VA supplementation to lactating mothers did not significantly lower child mortality. The World Health Organization (WHO) recently acknowledged that our understanding about the principle of VA allocation within the maternal system and the secretion into milk is too incomplete to devise an effective intervention.

METHODS

We present a secondary analysis of data collected among lactating mothers in VAD endemic northern Kenya (n = 171), examining nutritional, inflammatory, and ecological factors that might associate with maternal retinol allocation. Regression models were applied using the outcome milk-retinol allocation index: milk retinol/(milk retinol + serum retinol).

RESULTS

Ten percent of the sample was identified as VAD. The average milk retinol concentration was 0.1 μmo/L, grossly below what is considered minimally necessary for an infant (1 μmol/L). VAD mothers and mothers with inflammation did not seem to compromise their milk retinol even though their serum retinol was lower than non-VAD and noninflammation mothers. Breast milk fat concentration positively correlated with milk retinol but not with serum retinol.

CONCLUSIONS

This exploratory study contributes toward an understanding of maternal retinol allocation.

Short-Term Daily Consumption of Provitamin A Carotenoid-Biofortified Maize Has Limited Impact on Breast Milk Retinol Concentrations in Zambian Women Enrolled in a Randomized Controlled Feeding Trial

BACKGROUND

Provitamin A carotenoid-biofortified maize is a conventionally bred staple crop designed to help prevent vitamin A deficiency. Lactating women are a potential target group, because regularly eating biofortified maize may increase vitamin A in breast milk-a critical source of vitamin A for breastfeeding infants.

OBJECTIVE

We assessed whether daily consumption of biofortified orange maize would increase the retinol concentration in the breast milk of Zambian women.

METHODS

Lactating women (n = 149) were randomly assigned to receive orange maize delivering 600 μg retinol equivalents (REs)/d as carotenoid plus placebo (OM), low-carotenoid white maize plus 600 μg REs/d as retinyl palmitate (VA), or white maize plus placebo (WM). Boiled maize (287 g dry weight/d) was served as 2 meals/d, 6 d/wk for 3 wk. We measured initial and final breast milk plasma retinol and β-carotene concentrations, and plasma inflammatory protein concentrations.

RESULTS

Groups were comparable at enrollment, with an overall geometric mean milk retinol concentration of 0.95 μmol/L (95% CI: 0.86, 1.05 μmol/L); 56% of samples had milk retinol <1.05 μmol/L. Median capsule and maize intake was 97% and 258 g dry weight/d, respectively. Final milk β-carotene did not vary across groups (P = 0.76). Geometric mean (95% CI) milk retinol concentration tended to be higher in the OM [1.15 μmol/L (0.96, 1.39 μmol/L)] and VA [1.17 μmol/L (0.99, 1.38 μmol/L)] groups than in the WM group [0.91 μmol/L (0.72, 1.14 μmol/L); P = 0.13], and the proportion of women with milk retinol <1.05 μmol/L was 52.1%, 42.9%, and 36.7% in the WM, OM, and VA groups, respectively (P-trend = 0.16).

CONCLUSIONS

Daily biofortified maize consumption did not increase mean milk retinol concentration in lactating Zambian women; however, there was a plausible downward trend in the risk of low milk retinol across intervention groups. This trial was registered at clinicaltrials.gov as NCT01922713.

Vitamin A dynamics in breastmilk and liver stores: a life history perspective

OBJECTIVES

Newborns are dependent on breastmilk vitamin A for building hepatic stores of vitamin A that will become critical for survival after weaning. It has been documented that vitamin A concentrations in breastmilk decline across the first year postpartum in both well-nourished and malnourished populations. The reason for this decline has been assumed to be a sign of concurrently depleting maternal hepatic stores. This study investigates this assumption to clarify why the decline occurs, drawing on life history theory.

METHODS

A cross sectional survey was conducted among lactating mothers in Kenya in 2006. Data were used to examine (1) the relationship between liver vitamin A and time, (2) if the relationship between milk and liver vitamin A varies by time, and (3) by maternal parity.

RESULTS

The relationship between liver vitamin A and time fits the quadratic pattern with marginal significance (P = 0.071, n = 192); the liver vitamin A declined during early postpartum then recovered in late postpartum time, controlling covariates. The milk-liver vitamin A relationship varied by postpartum time periods (P = 0.03) and by maternal parity (P = 0.005). Mothers in earlier postpartum or higher parity had a stronger positive relationship between milk and liver vitamin A than mothers in later postpartum or lower parity.

CONCLUSIONS

Our observations are consistent with life history tradeoffs and negate the assumption that maternal hepatic and milk vitamin A decline together. Rather, maternal liver vitamin A has a dynamic relationship with milk vitamin A, particularly depending on postpartum time and maternal parity.

Lipid-soluble vitamins A, D, and E in HIV-infected pregnant women in Tanzania

BACKGROUND/OBJECTIVES

There is limited published research examining lipid-soluble vitamins in human immunodeficiency virus (HIV)-infected pregnant women, particularly in resource-limited settings.

SUBJECTS/METHODS

This is an observational analysis of 1078 HIV-infected pregnant women enrolled in a trial of vitamin supplementation in Tanzania. Baseline data on sociodemographic and anthropometric characteristics, clinical signs and symptoms, and laboratory parameters were used to identify correlates of low plasma vitamin A (<0.7 micromol/l), vitamin D (<80 nmol/l) and vitamin E (<9.7 micromol/l) status. Binomial regression was used to estimate risk ratios and 95% confidence intervals.

RESULTS

Approximately 35, 39 and 51% of the women had low levels of vitamins A, D and E, respectively. Severe anemia (hemoglobin <85 g/l; P<0.01), plasma vitamin E (P=0.02), selenium (P=0.01) and vitamin D (P=0.02) concentrations were significant correlates of low vitamin A status in multivariate models. Erythrocyte Sedimentation Rate (ESR) was independently related to low vitamin A status in a nonlinear manner (P=0.01). The correlates of low vitamin D status were CD8 cell count (P=0.01), high ESR (ESR >81 mm/h; P<0.01), gestational age at enrollment (nonlinear; P=0.03) and plasma vitamins A (P=0.02) and E (P=0.01). For low vitamin E status, the correlates were money spent on food per household per day (P<0.01), plasma vitamin A concentration (nonlinear; P<0.01) and a gestational age <16 weeks at enrollment (P<0.01).

CONCLUSIONS

Low concentrations of lipid-soluble vitamins are widely prevalent among HIV-infected women in Tanzania and are correlated with other nutritional insufficiencies. Identifying HIV-infected persons at greater risk of poor nutritional status and infections may help inform design and implementation of appropriate interventions.

Prevention of perinatal HIV transmission: a review of novel strategies

Significant progress has been made in preventing transmission of HIV-1 from mother to infant. With combination antiretroviral therapies, transmission rates lower than 2% have been achieved in clinical studies. Abbreviated regimens covering labour and the first few days of neonatal life have shown considerable promise in the developing world. Several questions and challenges remain, however. These include choice of the optimal antiretroviral agent(s) and duration of the regimens, availability of antiretroviral agents in developing countries, long-term safety of antiretrovirals during pregnancy and early neonatal life and the problem of breastfeeding transmission in countries where alternatives to breastfeeding are not available. A wider array of strategies for prevention of mother-to-child transmission of HIV-1 during breastfeeding, including passive and active immunisation, may offer much needed answers to the problem of continued HIV transmission from mother to infant.