Alice M Mwangi

Iron fortification adversely affects the gut microbiome, increases pathogen abundance and induces intestinal inflammation in Kenyan infants

Background In-home iron fortification for infants in developing countries is recommended for control of anaemia, but low absorption typically results in >80% of the iron passing into the colon. Iron is essential for growth and virulence of many pathogenic enterobacteria. We determined the effect of high and low dose in-home iron fortification on the infant gut microbiome and intestinal inflammation. Methods We performed two double-blind randomised controlled trials in 6-month-old Kenyan infants (n=115) consuming home-fortified maize porridge daily for 4 months. In the first, infants received a micronutrient powder (MNP) containing 2.5 mg iron as NaFeEDTA or the MNP without iron. In the second, they received a different MNP containing 12.5 mg iron as ferrous fumarate or the MNP without the iron. The primary outcome was gut microbiome composition analysed by 16S pyrosequencing and targeted real-time PCR (qPCR). Secondary outcomes included faecal calprotectin (marker of intestinal inflammation) and incidence of diarrhoea. We analysed the trials separately and combined. Results At baseline, 63% of the total microbial 16S rRNA could be assigned to Bifidobacteriaceae but there were high prevalences of pathogens, including Salmonella Clostridium difficile, Clostridium perfringens, and pathogenic Escherichia coli. Using pyrosequencing, +FeMNPs increased enterobacteria, particularly Escherichia/Shigella (p=0.048), the enterobacteria/bifidobacteria ratio (p=0.020), and Clostridium (p=0.030). Most of these effects were confirmed using qPCR; for example, +FeMNPs increased pathogenic E. coli strains (p=0.029). +FeMNPs also increased faecal calprotectin (p=0.002). During the trial, 27.3% of infants in +12.5 mgFeMNP required treatment for diarrhoea versus 8.3% in −12.5 mgFeMNP (p=0.092). There were no study-related serious adverse events in either group. Conclusions In this setting, provision of iron-containing MNPs to weaning infants adversely affects the gut microbiome, increasing pathogen abundance and causing intestinal inflammation. Trial registration number NCT01111864.

Biofortified yellow cassava and vitamin A status of Kenyan children: a randomized controlled trial.

BACKGROUND Whereas conventional white cassava roots are devoid of provitamin A, biofortified yellow varieties are naturally rich in β-carotene, the primary provitamin A carotenoid. OBJECTIVE We assessed the effect of consuming yellow cassava on serum retinol concentration in Kenyan schoolchildren with marginal vitamin A status. DESIGN We randomly allocated 342 children aged 5-13 y to receive daily, 6 d/wk, for 18.5 wk 1) white cassava and placebo supplement (control group), 2) provitamin A-rich cassava (mean content: 1460 μg β-carotene/d) and placebo supplement (yellow cassava group), and 3) white cassava and β-carotene supplement (1053 μg/d; β-carotene supplement group). The primary outcome was serum retinol concentration; prespecified secondary outcomes were hemoglobin concentration and serum concentrations of β-carotene, retinol-binding protein, and prealbumin. Groups were compared by using ANCOVA, adjusting for inflammation, baseline serum concentrations of retinol and β-carotene, and stratified design. RESULTS The baseline prevalence of serum retinol concentration <0.7 μmol/L and inflammation was 27% and 24%, respectively. For children in the control, yellow cassava, and β-carotene supplement groups, the mean daily intake of cassava was 378, 371, and 378 g, respectively, and the total daily supply of provitamin A and vitamin A from diet and supplements was equivalent to 22, 220, and 175 μg retinol, respectively. Both yellow cassava and β-carotene supplementation increased serum retinol concentration by 0.04 μmol/L (95% CI: 0.00, 0.07 μmol/L); correspondingly, serum β-carotene concentration increased by 524% (448%, 608%) and 166% (134%, 202%). We found no effect on hemoglobin concentration or serum concentrations of retinol-binding protein and prealbumin. CONCLUSIONS In our study population, consumption of yellow cassava led to modest gains in serum retinol concentration and a large increase in β-carotene concentration. It can be an efficacious, new approach to improve vitamin A status. This study was registered with clinicaltrials.gov as NCT01614483.

Biofortified Cassava with Pro-Vitamin A Is Sensory and Culturally Acceptable for Consumption by Primary School Children in Kenya

Background Biofortification of cassava with pro-vitamin A can potentially reduce vitamin A deficiency in low-income countries. However, little is known about consumer acceptance of this deep yellow variety of cassava compared to the commonly available white varieties. We aimed to determine the sensory and cultural acceptability of the consumption of pro-vitamin A rich cassava in order to identify key factors predicting the intention to consume pro-vitamin A rich cassava by families with school-aged children in Eastern Kenya. Methods Sensory acceptability was measured by replicated discrimination tests and paired preference tests among 30 children (7–12 yr) and 30 caretakers (18–45 yr) in three primary schools. Cultural acceptability was assessed with a questionnaire based on the combined model of The Theory of Planned Behavior and The Health Belief Model in one primary school among 140 caretakers of children aged 6 to 12 years. Correlations and multivariate analyses were used to determine associations between summed scores for model constructs. Results Caretakers and children perceived a significant difference in taste between white and pro-vitamin A rich cassava. Both preferred pro-vitamin A rich cassava over white cassava because of its soft texture, sweet taste and attractive color. Knowledge about pro-vitamin A rich cassava and its relation to health (‘Knowledge’ ((β = 0.29, P = <.01)) was a strong predictor of ‘Health behavior identity’. Worries related to bitter taste and color (‘Perceived barriers 1’ (β = −0.21, P = .02)), the belief of the caretaker about having control to prepare cassava (‘Control beliefs’ (β = 0.18, P = .02)) and activities like information sessions about pro-vitamin A rich cassava and recommendations from health workers (‘Cues to action’(β = 0.51, P = <.01)) were the best predictors of intention to consume pro-vitamin A rich cassava. Conclusions Pro-vitamin A rich cassava is well accepted by school children in our study population.

Iron status and systemic inflammation, but not gut inflammation, strongly predict gender-specific concentrations of serum hepcidin in infants in rural Kenya.

Hepcidin regulation by competing stimuli such as infection and iron deficiency has not been studied in infants and it’s yet unknown whether hepcidin regulatory pathways are fully functional in infants. In this cross-sectional study including 339 Kenyan infants aged 6.0±1.1 months (mean±SD), we assessed serum hepcidin-25, biomarkers of iron status and inflammation, and fecal calprotectin. Prevalence of inflammation, anemia, and iron deficiency was 31%, 71%, 26%, respectively. Geometric mean (±SD) serum hepcidin was 6.0 (±3.4) ng/mL, and was significantly lower in males than females. Inflammation (C-reactive protein and interleukin-6) and iron status (serum ferritin, zinc protoporphyrin and soluble transferrin receptor) were significant predictors of serum hepcidin, explaining nearly 60% of its variance. There were small, but significant differences in serum hepcidin comparing iron deficient anemic (IDA) infants without inflammation to iron-deficient anemic infants with inflammation (1.2 (±4.9) vs. 3.4 (±4.9) ng/mL; P<0.001). Fecal calprotectin correlated with blood/mucus in the stool but not with hepcidin. Similarly, the gut-linked cytokines IL-12 and IL-17 did not correlate with hepcidin. We conclude that hepcidin regulatory pathways are already functional in infancy, but serum hepcidin alone may not clearly discriminate between iron-deficient anemic infants with and without infection. We propose gender-specific reference values for serum hepcidin in iron-replete infants without inflammation.

Effect of Daily Antenatal Iron Supplementation on Plasmodium Infection in Kenyan Women: A Randomized Clinical Trial

IMPORTANCE Anemia affects most pregnant African women and is predominantly due to iron deficiency, but antenatal iron supplementation has uncertain health benefits and can increase the malaria burden. OBJECTIVE To measure the effect of antenatal iron supplementation on maternal Plasmodium infection risk, maternal iron status, and neonatal outcomes. DESIGN, SETTING, AND PARTICIPANTS Randomized placebo-controlled trial conducted October 2011 through April 2013 in a malaria endemic area among 470 rural Kenyan women aged 15 to 45 years with singleton pregnancies, gestational age of 13 to 23 weeks, and hemoglobin concentration of 9 g/dL or greater. All women received 5.7 mg iron/day through flour fortification during intervention, and usual intermittent preventive treatment against malaria was given. INTERVENTIONS Supervised daily supplementation with 60 mg of elemental iron (as ferrous fumarate, n = 237 women) or placebo (n = 233) from randomization until 1 month postpartum. MAIN OUTCOMES AND MEASURES Primary outcome was maternal Plasmodium infection at birth. Predefined secondary outcomes were birth weight and gestational age at delivery, intrauterine growth, and maternal and infant iron status at 1 month after birth. RESULTS Among the 470 participating women, 40 women (22 iron, 18 placebo) were lost to follow-up or excluded at birth; 12 mothers were lost to follow-up postpartum (5 iron, 7 placebo). At baseline, 190 of 318 women (59.7%) were iron-deficient. In intention-to-treat analysis, comparison of women who received iron vs placebo, respectively, yielded the following results at birth: Plasmodium infection risk: 50.9% vs 52.1% (crude difference, -1.2%, 95% CI, -11.8% to 9.5%; P = .83); birth weight: 3202 g vs 3053 g (crude difference, 150 g, 95% CI, 56 to 244; P = .002); birth-weight-for-gestational-age z score: 0.52 vs 0.31 (crude difference, 0.21, 95% CI, -0.11 to 0.52; P = .20); and at 1 month after birth: maternal hemoglobin concentration: 12.89 g/dL vs 11.99 g/dL (crude difference, 0.90 g/dL, 95% CI, 0.61 to 1.19; P < .001); geometric mean maternal plasma ferritin concentration: 32.1 µg/L vs 14.4 µg/L (crude difference, 123.4%, 95% CI, 85.5% to 169.1%; P < .001); geometric mean neonatal plasma ferritin concentration: 163.0 µg/L vs 138.7 µg/L (crude difference, 17.5%, 95% CI, 2.4% to 34.8%; P = .02). Serious adverse events were reported for 9 and 12 women who received iron and placebo, respectively. There was no evidence that intervention effects on Plasmodium infection risk were modified by intermittent preventive treatment use. CONCLUSIONS AND RELEVANCE Among rural Kenyan women with singleton pregnancies, administration of daily iron supplementation, compared with administration of placebo, resulted in no significant differences in overall maternal Plasmodium infection risk. Iron supplementation led to increased birth weight. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01308112.

Maize Porridge Enriched with a Micronutrient Powder Containing Low-Dose Iron as NaFeEDTA but Not Amaranth Grain Flour Reduces Anemia and Iron Deficiency in Kenyan Preschool Children

Few studies have evaluated the impact of fortification with iron-rich foods such as amaranth grain and multi-micronutrient powder (MNP) containing low doses of highly bioavailable iron to control iron deficiency anemia (IDA) in children. We assessed the efficacy of maize porridge enriched with amaranth grain or MNP to reduce IDA in Kenyan preschool children. In a 16-wk intervention trial, children (n = 279; 12-59 mo) were randomly assigned to: unrefined maize porridge (control; 4.1 mg of iron/meal; phytate:iron molar ratio 5:1); unrefined maize (30%) and amaranth grain (70%) porridge (amaranth group; 23 mg of iron/meal; phytate:iron molar ratio 3:1); or unrefined maize porridge with MNP (MNP group; 6.6 mg iron/meal; phytate:iron molar ratio 2.6:1; 2.5 mg iron as NaFeEDTA). Primary outcomes were anemia and iron status with treatment effects estimated relative to control. At baseline, 38% were anemic and 30% iron deficient. Consumption of MNP reduced the prevalence of anemia [-46% (95% CI: -67, -12)], iron deficiency [-70% (95% CI: -89, -16)], and IDA [-75% (95% CI: -92, -20)]. The soluble transferrin receptor [-10% (95% CI: -16, -4)] concentration was lower, whereas the hemoglobin (Hb) [2.7 g/L (95% CI: 0.4, 5.1)] and plasma ferritin [40% (95% CI: 10, 95)] concentrations increased in the MNP group. There was no significant change in Hb or iron status in the amaranth group. Consumption of maize porridge fortified with low-dose, highly bioavailable iron MNP can reduce the prevalence of IDA in preschool children. In contrast, fortification with amaranth grain did not improve iron status despite a large increase in iron intake, likely due to high ratio of phytic acid:iron in the meal.

Do street food vendors sell a sufficient variety of foods for a healthful diet? The case of Nairobi.

This study examined whether street food vendors sell a sufficient variety of foods for a healthful diet. It was hypothesized that vendors sold only low-cost food groups to enable the buyer to afford the food while the vendor also made a profit. A structured questionnaire was administered to 580 vendors in three selected locations. Data included product names, ingredients, methods of preparation, and the sex of the vendor. A little more than half of the vendors (53%) sold food of only one group; 44% sold cereals. Overall, 36% of vendors, mostly men, sold only carbohydrate products. the percentage of vendors selling foods of more than one group was higher in the working area (53%) than in the slum area (43%, p < .05), and it was higher in both of these areas taken together than in the lower-middle income area (21%, p < .001). Micronutrient and mixed-nutrient products were associated with female vendors. Although a slight majority of all street vendors sell foods of only one group, women vendors are capable of supplying a sufficient variety of food groups that consumers can afford. It appears that consumer purchasing power dictates the food groups provided by vendors, especially cereal-based-foods. A policy on micronutrient fortification of cereal flours and fats used in popular street food preparation needs to be considered. This could be coupled with consumer and vendor education programs focusing on the importance of healthful diets.

The role of street foods in the dietary pattern of two low-income groups in Nairobi.

Objectives: To examine the frequency of street food consumption of people living in low-income settlements in Nairobi and the role of street foods in their daily diet and to reveal why people consume street foods rather than home-prepared foods.Setting, subjects and methods: A cross-sectional descriptive study was done with 1011 households and in-depth interviews with a subsample of 73 households in two selected areas in Nairobi: Korogocho, a low-income slum area and Dandora, a low–middle-income area.Results: The frequency of street food consumption was higher in Korogocho than in Dandora (3.6 vs 2.0 days per week; P<0.001). Street food consumption did not differ between different types of households, with the exception of household size. Employment status of the household head and street food consumption were related (P<0.001): consumption frequency of 3.7 days per week when irregularly or unemployed, 2.9 days/week when self-employed and 2.1 days/week when regularly employed. Furthermore, where an adult woman with primarily a domestic role was present, street food consumption was less (2.55 days per week when present vs 2.95 when not present; P<0.05).Conclusions: Street foods play an important role in the diet of poor households in Nairobi, in particular for breakfast and snacks, because they are cheap and convenient. The frequency of street food consumption is determined by a combination of at least four factors: level of household income; regularity of income; household size; and time available to prepare meals.Sponsorship: The project is financed by the Netherlands Foundation for the Advancement of Tropical Research (WOTRO), filenumber WV 96-153.European Journal of Clinical Nutrition (2001) 55, 562–570

The ecology of street foods in Nairobi

Very little is known about street foods in sub‐Sahara Africa. We investigated the scope of the street food phenomenon in Nairobi, both in the past and present, with the aim of establishing circumstances surrounding its practice and its function in the urban food supply. We found that street food vending and consumption in Nairobi rapidly increased during the previous two decades, instigated by the need for affordable food among low‐income urban dwellers and the need for employment. It is an expanding and thriving phenomenon, especially among the urban poor, and climbs up the socio‐economic ladder due to increasing monetary demands. In addition to being a food supply channel for the urban poor, street food vending in Nairobi provides employment opportunities to a labour force that would otherwise be unemployed. There is need to legitimize the sector with simple regulations that make the food safe but not expensive.

Sensory Acceptability and Factors Predicting the Consumption of Grain Amaranth in Kenya

This study investigated the effect of adding grain amaranth flour on sensory acceptability of maize porridge in Kenya. Factors influencing the intention of mothers to feed their children on grain amaranth were identified. A significant difference between the various porridge ratios (50:50, 70:30, and 100:0 amaranth:maize) either in unfermented or fermented form could be detected. Preference for the unfermented amaranth enriched maize porridge was observed. Intention significantly correlated and predicted grain amaranth consumption (p < .001). Knowledge and health value significantly predicted health behavior identity. Interaction between barriers and intention negatively influenced behavior. Findings suggest that unfermented amaranth enriched maize porridge is acceptable. Unfermented porridge with 70% amaranth can be considered for use in a program aimed at increasing dietary iron intake among children. Increasing awareness about micronutrient deficiencies and nutritional benefits of grain amaranth could enhance its consumption.