Biofortified and fortified maize consumption reduces prevalence of low milk retinol, but does not increase vitamin A stores of breastfeeding Zambian infants with adequate reserves: a randomized controlled trial

Projecting the Contribution of Provitamin A Maize Biofortification and Other Nutrition Interventions to the Nutritional Adequacy and Cost of Diets in Rural Zimbabwe

BACKGROUND

Evidence of the effectiveness of biofortified maize with higher provitamin A (PVA) to address vitamin A deficiency in rural Africa remains scant.

OBJECTIVES

This study projects the impact of adopting PVA maize for a diversity of households in an area typical of rural Zimbabwe and models the cost and composition of diets adequate in vitamin A.

METHODS

Household-level weighed food records were generated from 30 rural households during a week in April and November 2021. Weekly household intakes were calculated, as well as indicative costs of diets using data from market surveys. The impact of PVA maize adoption was modeled assuming all maize products contained observed vitamin A concentrations. The composition and cost of the least expensive indicative diets adequate in vitamin A were calculated using linear programming.

RESULTS

Very few households would reach adequate intake of vitamin A with the consumption of PVA maize. However, from a current situation of 33%, 50%-70% of households were projected to reach ≤50% of their requirements (the target of PVA), even with the modest vitamin A concentrations achieved on-farm (mean of 28.3 μg RAE per 100 g). This proportion would increase if higher concentrations recorded on-station were achieved. The estimated daily costs of current diets (mean ± standard deviation) were USD 1.43 ± 0.59 in the wet season and USD 0.96 ± 0.40 in the dry season. By comparison, optimization models suggest that diets adequate in vitamin A could be achieved at daily costs of USD 0.97 and USD 0.79 in the wet and dry seasons, respectively.

CONCLUSIONS

The adoption of PVA maize would bring a substantial improvement in vitamin A intake in rural Zimbabwe but should be combined with other interventions (e.g., diet diversification) to fully address vitamin A deficiency.

Transforming Nigerian Food Systems Through Their Backbones: Lessons From a Decade of Staple Crop Biofortification Programing

This article presents the evolution of the biofortification program in Nigeria over the last decade and the role of interdisciplinary research in informing cost-effective, efficient, and inclusive development; implementation; and scaling of this program. Launched in 2011 to improve Nigeria's food systems to deliver accessible and affordable nutrients through commonly consumed staples, the Nigeria biofortification program was implemented through an effective partnership between the CGIAR and public, private, and civil society sectors at federal, state, and local levels. By the end of 2021, several biofortified varieties of Nigeria's 2 main staples, namely cassava and maize, were officially released for production by smallholders, with several biofortified varieties of other key staples (including pearl millet, rice, and sorghum) either under testing or in the release pipeline. In 2021, the program was estimated to benefit 13 million Nigerians consuming biofortified cassava and maize varieties. The evidence on the nutritional impact, consumer and farmer acceptance, and cost-effective scalability of biofortified crops documented by the program resulted in the integration of biofortified crops in several key national public policies and social protection programs; private seed and food company products/investments, as well as in humanitarian aid.

Child Health, Agriculture and Integrated Nutrition (CHAIN): protocol for a randomised controlled trial of improved infant and young child feeding in rural Zimbabwe

INTRODUCTION

Over one-quarter of children in sub-Saharan Africa are stunted; however, commercial supplements only partially meet child nutrient requirements, cannot be sustainably produced, and do not resolve physiological barriers to adequate nutrition (eg, inflammation, microbiome dysbiosis and metabolic dysfunction). Redesigning current infant and young child feeding (IYCF) interventions using locally available foods to improve intake, uptake and utilisation of nutrients could ameliorate underlying pathogenic pathways and improve infant growth during the critical period of complementary feeding, to reduce the global burden of stunting.

METHODS AND ANALYSIS

Child Health Agriculture Integrated Nutrition is an open-label, individual household randomised trial comparing the effects of IYCF versus 'IYCF-plus' on nutrient intake during infancy. The IYCF intervention comprises behaviour change modules to promote infant nutrition delivered by community health workers, plus small-quantity lipid-based nutrient supplements from 6 to 12 months of age which previously reduced stunting at 18 months of age by ~20% in rural Zimbabwe. The 'IYCF-plus' intervention provides these components plus powdered NUA-45 biofortified sugar beans, whole egg powder, moringa leaf powder and provitamin A maize. The trial will enrol 192 infants between 5 and 6 months of age in Shurugwi district, Zimbabwe. Research nurses will collect data plus blood, urine and stool samples at baseline (5-6 months of age) and endline (9-11 months of age). The primary outcome is energy intake, measured by multipass 24-hour dietary recall at 9-11 months of age. Secondary outcomes include nutrient intake, anthropometry and haemoglobin concentration. Nested laboratory substudies will evaluate the gut microbiome, environmental enteric dysfunction, metabolic phenotypes and innate immune function. Qualitative substudies will explore the acceptability and feasibility of the IYCF-plus intervention among participants and community stakeholders, and the effects of migration on food production and consumption.

ETHICS AND DISSEMINATION

This trial is registered at ClinicalTrials.gov (NCT04874688) and was approved by the Medical Research Council of Zimbabwe (MRCZ/A/2679) with the final version 1.4 approved on 20 August 2021, following additional amendments. Dissemination of trial results will be conducted through the Community Engagement Advisory Board in the study district and through national-level platforms.

TRIAL REGISTRATION NUMBER

NCT04874688.

Vitamin A Concentration in Human Milk: A Meta-Analysis

Humans require vitamin A (VA). However, pooled VA data in human milk is uncommon internationally and offers little support for dietary reference intake (DRIs) revision of infants under 6 months. As a result, we conducted a literature review and a meta-analysis to study VA concentration in breast milk throughout lactation across seven databases by August 2021. Observational or intervention studies involving nursing mothers between the ages of 18 and 45, with no recognized health concerns and who had full-term infants under 48 months were included. Studies in which retinol concentration was expressed as a mass concentration on a volume basis and determined using high-, ultra-, or ultra-fast performance liquid chromatography (HPLC, UPLC, or UFLC) were chosen. Finally, 76 papers involving 9171 samples published between 1985 and 2021 qualified for quantitative synthesis. Results from the random-effects model showed that the VA concentration of healthy term human milk decreased significantly as lactation progressed. VA (µg/L) with 95% CI at the colostrum, transitional, early mature and late mature stages being 920.7 (744.5, 1095.8), 523.7 (313.7, 733.6), 402.4 (342.5, 462.3) and 254.7 (223.7, 285.7), respectively (X2 = 71.36, p < 0.01). Subgroup analysis revealed no significant differences identified in VA concentration (µg/L) between Chinese and non-Chinese samples at each stage, being 1039.1 vs. 895.8 (p = 0.64), 505.7 vs. 542.2(p = 0.88), 408.4 vs. 401.2 (p = 0.92), 240.0 vs. 259.3 (p = 0.41). The findings have significant implications for the revision of DRIs for infants under six months.

Health outcomes associated with micronutrient-fortified complementary foods in infants and young children aged 6–23 months: a systematic review and meta-analysis

Background

Appropriate feeding of infants and young children is essential for healthy growth and the prevention of stunting, wasting, and overweight. We aimed to assess the beneficial versus harmful effects of providing fortified complementary foods to children in the complementary feeding period.

Methods

In this systematic review and meta-analysis, we searched the databases Cochrane Central Register of Controlled Trials, MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature, Global Index Medicus, Web of Science, ClinicalTrials.gov, and WHO International Clinical Trials Registry Platform from inception to March 9, 2021. We included randomised controlled trials and controlled clinical trials done in infants and children aged 6–23 months with no identified health problems. Consumption of foods fortified centrally (ie, during industrial processing) with one micronutrient or a combination of vitamins, minerals, or both was compared with the same complementary foods, but without micronutrient fortification. Two review authors independently screened studies for eligibility, extracted data, assessed risk of bias, and rated the certainty of the evidence. The main outcomes were growth (measured by Z scores for weight for age, weight for height or length, and height or length for age, or other growth measures), stunting, wasting, nutrient adequacy or excess, anaemia, haemoglobin concentration, iron status, serum zinc concentration, and serum retinol concentration. We used a random-effects meta-analysis for combining data. This study is registered with PROSPERO, CRD42021245876.

Findings

We included 16 studies with 6423 participants, 13 of which were done in malaria-endemic areas. Overall, 12 studies were included in the quantitative syntheses. We identified five further ongoing studies. There was no difference between participants who received fortified complementary foods and those who received non-fortified complementary foods in weight-for-age Z scores (mean difference −0·01, 95% CI −0·07 to 0·06; five trials; 1206 participants; moderate-certainty evidence), weight-for-height or length Z scores (−0·05, −0·19 to 0·10; four trials; 1109 participants; moderate-certainty evidence), and height or length-for-age Z scores (−0·01, −0·21 to 0·20; four trials; 811 participants; low-certainty evidence); stunting and wasting were not assessed in any study as outcomes. Moderate-certainty evidence from six trials with 1209 patients showed that providing fortified complementary foods to children aged 6–23 months reduced the risk of anaemia (risk ratio 0·57, 95% CI 0·39 to 0·82). Those who received fortified complementary foods compared with those who did not had higher haemoglobin concentrations (mean difference 3·44 g/L, 95% CI 1·33 to 5·55; 11 trials; 2175 participants; moderate-certainty evidence) and ferritin concentration (0·43 μg/L on log scale, 0·14 to 0·72; six trials; 903 participants; low-certainty evidence). The intervention led to no effects on serum zinc concentration (−0·13 g/dL, −0·82 to 0·56; two trials; 333 participants; low-certainty evidence) and serum retinol concentration (0·03 μmol/L, −0·02 to 0·08; five trials; 475 participants; moderate-certainty evidence).

Interpretation

Fortified complementary foods are effective strategies to prevent anaemia in infants and young children aged 6–23 months in malaria-endemic regions. Effects of complementary food fortification should be further investigated in low-income and middle-income countries, but should also be assessed in high-income countries, and in regions where malaria is not endemic.

Funding

WHO.

Time Since Dose and Dietary Vitamin A Intake Affect Tracer Mixing in the 13C-Retinol Isotope Dilution Test in Male Rats

BACKGROUND

Retinol isotope dilution (RID) estimates total liver vitamin A reserves (TLRs), the gold-standard vitamin A (VA) biomarker. RID equation assumptions are based on limited data.

OBJECTIVES

We measured the impact of tracer choice, mixing period, and VA intake on tracer mixing [ratio of tracer enrichment in serum to that in liver stores (S)] in VA-deficient, -adequate, and hypervitaminotic rats.

METHODS

Study 1 was a 3 × 2 × 3 design (18 groups, n = 5/group). Male Sprague-Dawley rats (21 d old) received 50, 100, or 3500 nmol VA/d for 21 d, were administered 52 nmol 13C2- or 13C10-retinyl acetate orally, and killed 5, 10, or 15 d later. Unlabeled VA (50 nmol/d) was given on days 11-14. Study 2 used 100 nmol VA/d for 21 d with 3 groups (n = 6-7): 52 nmol 13C2- or 13C10-retinyl acetate and 100 nmol VA/d throughout 14-d mixing, or 13C2-retinyl acetate without VA. Repeated-measures, 1-factor, and 3-factor ANOVAs were used for analysis.

RESULTS

Mean ± SD TLRs (μmol/g liver) reflected intake: 0.11 ± 0.04 (50 nmol VA/d), 0.16 ± 0.04 (100 nmol VA/d), and 5.07 ± 1.58 (3500 nmol VA/d) in Study 1 and 0.24 ± 0.08 (100 nmol VA/d) in Study 2. In Study 1, mean ± SD S was 1.65 ± 0.26 (5 d), 1.16 ± 0.09 (10 d), and 0.92 ± 0.08 (15 d). The interactions tracer*VA intake and time*VA intake were significant between days 10 and 15 (P < 0.05). In Study 2, mean ± SD S was 1.07 ± 0.02 without VA during mixing, and 0.81 ± 0.04 (13C2) and 0.79 ± 0.03 (13C10) with VA intake throughout. Estimated:measured TLRs varied by VA intake and time in Study 1 but not between groups in Study 2.

CONCLUSIONS

The 13C-content effect on RID through S is inconsistent. S is highly variable at 5 d, contraindicating early-time point RID. VA intake effects on S vary with timing and quantity. Assuming S = 0.8 at 14 d with consistent VA intake in human studies is likely appropriate.

Evidence to Underpin Vitamin A Requirements and Upper Limits in Children Aged 0 to 48 Months: A Scoping Review

Vitamin A deficiency is a major health risk for infants and children in low- and middle-income countries. This scoping review identified, quantified, and mapped research for use in updating nutrient requirements and upper limits for vitamin A in children aged 0 to 48 months, using health-based or modelling-based approaches. Structured searches were run on Medline, EMBASE, and Cochrane Central, from inception to 19 March 2021. Titles and abstracts were assessed independently in duplicate, as were 20% of full texts. Included studies were tabulated by question, methodology and date, with the most relevant data extracted and assessed for risk of bias. We found that the most recent health-based systematic reviews and trials assessed the effects of supplementation, though some addressed the effects of staple food fortification, complementary foods, biofortified maize or cassava, and fortified drinks, on health outcomes. Recent isotopic tracer studies and modelling approaches may help quantify the effects of bio-fortification, fortification, and food-based approaches for increasing vitamin A depots. A systematic review and several trials identified adverse events associated with higher vitamin A intakes, which should be useful for setting upper limits. We have generated and provide a database of relevant research. Full systematic reviews, based on this scoping review, are needed to answer specific questions to set vitamin A requirements and upper limits.