A multi-micronutrient beverage enhances the vitamin A and zinc status of Nigerian primary schoolchildren

Effects of Foods Fortified with Zinc, Alone or Cofortified with Multiple Micronutrients, on Health and Functional Outcomes: A Systematic Review and Meta-Analysis

Seventeen per cent of the world's population is estimated to be at risk of inadequate zinc intake, which could in part be addressed by zinc fortification of widely consumed foods. We conducted a review of efficacy and effectiveness studies to ascertain the effect of zinc fortification [postharvest fortification of an industrially produced food or beverage; alone or with multiple micronutrients (MMN)] on a range of health outcomes. Previous reviews have required that the effect of zinc be isolated; because zinc is always cofortified with MMN in existing fortification programs, we did not impose this condition. Outcomes assessed were zinc-related biomarkers (plasma or serum, hair or urine zinc concentrations, comet assay, plasma fatty acid concentrations, and the proportion of and total zinc absorbed in the intestine from the diet), child anthropometry, morbidity, mortality, cognition, plasma or serum iron and copper concentrations, and for observational studies, a change in consumption of the food vehicle. Fifty-nine studies were included in the review; 54 in meta-analyses, totaling 73 comparisons. Zinc fortification with and without MMN increased plasma zinc concentrations (efficacy, n = 27: 4.68 μg/dL; 95% CI: 2.62-6.75; effectiveness, n = 13: 6.28 μg/dL; 95% CI: 5.03-7.77 μg/dL) and reduced the prevalence of zinc deficiency (efficacy, n = 11: OR: 0.76, 95% CI: 0.60-0.96; effectiveness, n = 10: OR: 0.45, 95% CI: 0.31-0.64). There were statistically significant increases in child weight (efficacy, n = 11: 0.43 kg, 95% CI: 0.11-0.75 kg), improvements in short-term auditory memory (efficacy, n = 3: 0.32 point, 95% CI: 0.13-0.50 point), and decreased incidence of diarrhea (efficacy, n = 3: RR: 0.79, 95% CI: 0.68-0.92) and fever (efficacy, n = 2: RR: 0.85, 95% CI: 0.74-0.97). However, these effects cannot be solely attributed to zinc. Our review found that zinc fortification with or without MMN reduced the prevalence of zinc deficiency and may provide health and functional benefits, including a reduced incidence of diarrhea.

Food fortification with multiple micronutrients: impact on health outcomes in general population

BACKGROUND

Vitamins and minerals are essential for growth and maintenance of a healthy body, and have a role in the functioning of almost every organ. Multiple interventions have been designed to improve micronutrient deficiency, and food fortification is one of them.

OBJECTIVES

To assess the impact of food fortification with multiple micronutrients on health outcomes in the general population, including men, women and children.

SEARCH METHODS

We searched electronic databases up to 29 August 2018, including the Cochrane Central Register of Controlled Trial (CENTRAL), the Cochrane Effective Practice and Organisation of Care (EPOC) Group Specialised Register and Cochrane Public Health Specialised Register; MEDLINE; Embase, and 20 other databases, including clinical trial registries. There were no date or language restrictions. We checked reference lists of included studies and relevant systematic reviews for additional papers to be considered for inclusion.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), cluster-RCTs, quasi-randomised trials, controlled before-after (CBA) studies and interrupted time series (ITS) studies that assessed the impact of food fortification with multiple micronutrients (MMNs). Primary outcomes included anaemia, micronutrient deficiencies, anthropometric measures, morbidity, all-cause mortality and cause-specific mortality. Secondary outcomes included potential adverse outcomes, serum concentration of specific micronutrients, serum haemoglobin levels and neurodevelopmental and cognitive outcomes. We included food fortification studies from both high-income and low- and middle-income countries (LMICs).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened, extracted and quality-appraised the data from eligible studies. We carried out statistical analysis using Review Manager 5 software. We used random-effects meta-analysis for combining data, as the characteristics of study participants and interventions differed significantly. We set out the main findings of the review in 'Summary of findings' tables, using the GRADE approach.

MAIN RESULTS

We identified 127 studies as relevant through title/abstract screening, and included 43 studies (48 papers) with 19,585 participants (17,878 children) in the review. All the included studies except three compared MMN fortification with placebo/no intervention. Two studies compared MMN fortification versus iodised salt and one study compared MMN fortification versus calcium fortification alone. Thirty-six studies targeted children; 20 studies were conducted in LMICs. Food vehicles used included staple foods, such as rice and flour; dairy products, including milk and yogurt; non-dairy beverages; biscuits; spreads; and salt. Fourteen of the studies were fully commercially funded, 13 had partial-commercial funding, 14 had non-commercial funding and two studies did not specify the source of funding. We rated all the evidence as of low to very low quality due to study limitations, imprecision, high heterogeneity and small sample size. When compared with placebo/no intervention, MMN fortification may reduce anaemia by 32% (risk ratio (RR) 0.68, 95% confidence interval (CI) 0.56 to 0.84; 11 studies, 3746 participants; low-quality evidence), iron deficiency anaemia by 72% (RR 0.28, 95% CI 0.19 to 0.39; 6 studies, 2189 participants; low-quality evidence), iron deficiency by 56% (RR 0.44, 95% CI 0.32 to 0.60; 11 studies, 3289 participants; low-quality evidence); vitamin A deficiency by 58% (RR 0.42, 95% CI 0.28 to 0.62; 6 studies, 1482 participants; low-quality evidence), vitamin B2 deficiency by 64% (RR 0.36, 95% CI 0.19 to 0.68; 1 study, 296 participants; low-quality evidence), vitamin B6 deficiency by 91% (RR 0.09, 95% CI 0.02 to 0.38; 2 studies, 301 participants; low-quality evidence), vitamin B12 deficiency by 58% (RR 0.42, 95% CI 0.25 to 0.71; 3 studies, 728 participants; low-quality evidence), weight-for-age z-scores (WAZ) (mean difference (MD) 0.1, 95% CI 0.02 to 0.17; 8 studies, 2889 participants; low-quality evidence) and weight-for-height/length z-score (WHZ/WLZ) (MD 0.1, 95% CI 0.02 to 0.18; 6 studies, 1758 participants; low-quality evidence). We are uncertain about the effect of MMN fortification on zinc deficiency (RR 0.84, 95% CI 0.65 to 1.08; 5 studies, 1490 participants; low-quality evidence) and height/length-for-age z-score (HAZ/LAZ) (MD 0.09, 95% CI 0.01 to 0.18; 8 studies, 2889 participants; low-quality evidence). Most of the studies in this comparison were conducted in children. Subgroup analyses of funding sources (commercial versus non-commercial) and duration of intervention did not demonstrate any difference in effects, although this was a relatively small number of studies and the possible association between commercial funding and increased effect estimates has been demonstrated in the wider health literature. We could not conduct subgroup analysis by food vehicle and funding; since there were too few studies in each subgroup to draw any meaningful conclusions. When we compared MMNs versus iodised salt, we are uncertain about the effect of MMN fortification on anaemia (R 0.86, 95% CI 0.37 to 2.01; 1 study, 88 participants; very low-quality evidence), iron deficiency anaemia (RR 0.40, 95% CI 0.09 to 1.83; 2 studies, 245 participants; very low-quality evidence), iron deficiency (RR 0.98, 95% CI 0.82 to 1.17; 1 study, 88 participants; very low-quality evidence) and vitamin A deficiency (RR 0.19, 95% CI 0.07 to 0.55; 2 studies, 363 participants; very low-quality evidence). Both of the studies were conducted in children. Only one study conducted in children compared MMN fortification versus calcium fortification. None of the primary outcomes were reported in the study. None of the included studies reported on morbidity, adverse events, all-cause or cause-specific mortality.

AUTHORS' CONCLUSIONS

The evidence from this review suggests that MMN fortification when compared to placebo/no intervention may reduce anaemia, iron deficiency anaemia and micronutrient deficiencies (iron, vitamin A, vitamin B2 and vitamin B6). We are uncertain of the effect of MMN fortification on anthropometric measures (HAZ/LAZ, WAZ and WHZ/WLZ). There are no data to suggest possible adverse effects of MMN fortification, and we could not draw reliable conclusions from various subgroup analyses due to a limited number of studies in each subgroup. We remain cautious about the level of commercial funding in this field, and the possibility that this may be associated with higher effect estimates, although subgroup analysis in this review did not demonstrate any impact of commercial funding. These findings are subject to study limitations, imprecision, high heterogeneity and small sample sizes, and we rated most of the evidence low to very low quality. and hence no concrete conclusions could be drawn from the findings of this review.

Are Low Intakes and Deficiencies in Iron, Vitamin A, Zinc, and Iodine of Public Health Concern in Ethiopian, Kenyan, Nigerian, and South African Children and Adolescents?

OBJECTIVE

To perform a systematic review to evaluate iron, vitamin A, zinc, and iodine status and intakes in children and adolescents (0-19 years) in Ethiopia, Kenya, Nigeria, and South Africa.

METHOD

Both national and subnational data published from the year 2005 to 2015 were searched via MEDLINE, Scopus, and national public health websites. For each micronutrient and country, status data from relevant studies and surveys were combined into an average prevalence and weighted by sample size (WAVG). Inadequate intakes were estimated from mean (SD) intakes.

RESULTS

This review included 55 surveys and studies, 17 from Ethiopia, 11 from Kenya, 12 from Nigeria, and 16 from South Africa. The WAVG prevalence of anemia ranged from 25% to 53%, iron deficiency from 12% to 29%, vitamin A deficiency (VAD) from 14% to 42%, zinc deficiency from 32% to 63%, and iodine deficiency from 15% to 86% in children aged 0 to 19 years from 4 countries. Generally, children <5 years had higher prevalence of anemia (32%-63%), VAD (15%-35%), and zinc deficiency (35%-63%) compared to children aged 5 to 19 years. Studies with intake data indicated that inadequate intakes ranged from 51% to 99% for zinc, 13% to 100% for iron, and 1% to 100% for vitamin A. Households failing to consume adequately iodized (>15 ppm) salt ranged from 2% in Kenya to 96% in Ethiopia.

CONCLUSION

With large variation within the 4 African countries, our data indicate that anemia and vitamin A, zinc, and iodine deficiencies are problems of public health significance. Effective public health strategies such as dietary diversification and food fortification are needed to improve micronutrient intake in both younger and older children.

Fortification of staple foods with zinc for improving zinc status and other health outcomes in the general population

BACKGROUND

Zinc deficiency is a global nutritional problem, particularly in children and women residing in settings where diets are cereal based and monotonous. It has several negative health consequences. Fortification of staple foods with zinc may be an effective strategy for preventing zinc deficiency and improving zinc-related health outcomes.

OBJECTIVES

To evaluate the beneficial and adverse effects of fortification of staple foods with zinc on health-related outcomes and biomarkers of zinc status in the general population.

SEARCH METHODS

We searched the following databases in April 2015: Cochrane Central Register of Controlled Trials (CENTRAL, Issue 3 of 12, 2015, the Cochrane Library), MEDLINE & MEDLINE In Process (OVID) (1950 to 8 April 2015), EMBASE (OVID) (1974 to 8 April 2015), CINAHL (1982 to April 2015), Web of Science (1900 to 9 April 2015), BIOSIS (1969 to 9 April 2015), POPLINE (1970 to April 2015), AGRICOLA, OpenGrey, BiblioMap, and Trials Register of Promoting Health Interventions (TRoPHI), besides regional databases (April 2015) and theses. We also searched clinical trial registries (17 March 2015) and contacted relevant organisations (May 2014) in order to identify ongoing and unpublished studies.

SELECTION CRITERIA

We included randomised controlled trials, randomised either at the level of the individual or cluster. We also included non-randomised trials at the level of the individual if there was a concurrent comparison group. We included non-randomised cluster trials and controlled before-after studies only if there were at least two intervention sites and two control sites. Interventions included fortification (central/industrial) of staple foods (cereal flours, edible fats, sugar, condiments, seasonings, milk and beverages) with zinc for a minimum period of two weeks. Participants were members of the general population who were over two years of age (including pregnant and lactating women) from any country.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility of studies for inclusion, extracted data from included studies, and assessed the risk of bias of the included studies.

MAIN RESULTS

We included eight trials (709 participants); seven were from middle-income countries of Asia, Africa, Europe, and Latin America where zinc deficiency is likely to be a public health problem. Four trials compared the effect of zinc-fortified staple foods with unfortified foods (comparison 1), and four compared zinc-fortified staple foods in combination with other nutrients/factors with the same foods containing other nutrients or factors without zinc (comparison 2). The interventions lasted between one and nine months. We categorised most trials as having unclear or high risk of bias for randomisation, but low risk of bias for blinding and attrition. None of the studies in comparison 1 reported data on zinc deficiency.Foods fortified with zinc increased the serum or plasma zinc levels in comparison to foods without added zinc (mean difference (MD) 2.12 µmol/L, 95% confidence interval (CI) 1.25 to 3.00 µmol/L; 3 studies; 158 participants; low-quality evidence). Participants consuming foods fortified with zinc versus participants consuming the same food without zinc had similar risk of underweight (average risk ratio 3.10, 95% CI 0.52 to 18.38; 2 studies; 397 participants; low-quality evidence) and stunting (risk ratio (RR) 0.88, 95% CI 0.36 to 2.13; 2 studies; 397 participants; low-quality evidence). A single trial of addition of zinc to iron in wheat flour did not find a reduction in proportion of zinc deficiency (RR 0.17, 95% CI 0.01 to 3.94; very low-quality evidence). We did not find a difference in serum or plasma zinc levels in participants consuming foods fortified with zinc plus other micronutrients when compared with participants consuming the same foods with micronutrients but no added zinc (MD 0.03 µmol/L, 95% CI -0.67 to 0.72 µmol/L; 4 studies; 250 participants; low-quality evidence). No trial in comparison 2 provided information about underweight or stunting.There was no reported adverse effect of fortification of foods with zinc on indicators of iron or copper status.

AUTHORS' CONCLUSIONS

Fortification of foods with zinc may improve the serum zinc status of populations if zinc is the only micronutrient used for fortification. If zinc is added to food in combination with other micronutrients, it may make little or no difference to the serum zinc status. Effects of fortification of foods with zinc on other outcomes including zinc deficiency, children's growth, cognition, work capacity of adults, or on haematological indicators are unknown. Given the small number of trials and participants in each trial, further investigation of these outcomes is required.

Multiple-Micronutrient Fortified Non-Dairy Beverage Interventions Reduce the Risk of Anemia and Iron Deficiency in School-Aged Children in Low-Middle Income Countries: A Systematic Review and Meta-Analysis (i-iv)

Multiple-micronutrient (MMN) fortification of beverages may be an effective option to deliver micronutrients to vulnerable populations. The aim of the present systematic review and meta-analysis is to evaluate the nutritional impacts of MMN fortified beverages in the context of low-middle income countries. A systematic search of published literature yielded 1022 citations, of which 10 randomized controlled trials (nine in school-aged children and one in pregnant women) met inclusion criteria. Results of school-aged children were included in the meta-analysis. Compared to iso-caloric controls, children who received MMN fortified beverages for 8 weeks to 6 months showed significant improvements in hemoglobin (+2.76 g/L, 95% CI [1.19, 4.33], p = 0.004; 8 studies) and serum ferritin (+15.42 pmol/L, [5.73, 25.12], p = 0.007; 8 studies); and reduced risk of anemia (RR 0.58 [0.29, 0.88], p = 0.005; 6 studies), iron deficiency (RR 0.34 [0.21, 0.55], p = 0.002; 7 studies), and iron deficiency anemia (RR 0.17 [0.06, 0.53], p = 0.02; 3 studies). MMN fortified beverage interventions could have major programmatic implications for reducing the burden of anemia and iron deficiency in school-aged children in low-middle income countries. Additional research is needed to investigate effects on other biochemical outcomes and population subgroups.

Assessment of a portable device to quantify vitamin A in fortified foods (flour, sugar, and milk) for quality control

BACKGROUND

Simple-to-use quantitative methods are needed to check the adequacy of vitamin A fortification levels.

OBJECTIVE

To assess the capacity of a portable fluorometer (iCheck FLUORO) and its test kit vials (iEx Mila) to quantify retinyl palmitate in fortified milks, flours (wheat, maize), and sugar.

METHODS

The portable fluorometer was assessed in a three-step procedure to determine its working range and linearity, intra-assay precision, and interperson precision. Measurements were compared with the results obtained by high-performance liquid chromatography (HPLC), commonly regarded as the standard method for vitamin A analysis.

RESULTS

The portable fluorometer (iCheck FLUORO) and its test kit vials (iEx Mila) precisely determined the vitamin A contents in fortifed flours, sugar, and milks. Its working range was 1 to 10, 0.5 to 3.0, and 5 to 15 mg retinol equivalents (RE) kg(-1) for flours (wheat and corn), milks, and sugar, respectively; these values are in accordance with the World Health Organization recommendations for food fortification in least developed countries. The limits of detection are higher than those of HPLC but are all satisfactory (< 1.46 mg RE kg(-1)). The coefficients of variation within and between observers were satisfactory, especially for sugar and milk.

CONCLUSIONS

The linear relationship between the data from the portable fluorometer and the HPLC data confirms that the portable fluorometer provides a good determination of the vitamin A content of the fortified products in the tested range.

Influence of micronutrient status and socioeconomic gradient on growth indices of 2-18-year-old Indian girls

Micronutrient deficiencies are common consequences of the plant-based diet in children from developing countries which may affect their linear and ponderal growth. The aim of the study was to investigate the association between micronutrient status and growth indices in Indian girls. In cross-sectional studies (2006-2010), data on weight, height and diet were collected on 1302 girls (2-18 years) from Pune city, India. Fasting hemoglobin was measured on 1118 girls and serum zinc was measured on 695 girls. Height-for-age Z-scores (HAZ) and body mass index for age Z-score (BMIZ) were computed using contemporary Indian references. HAZ >-1 was observed in 54% girls, and 18.1% were short (HAZ <-2). BMIZ was within the reference range (-2<BMIZ<2) in majority (82.4%) of the girls. Average HAZ and BMIZ were significantly higher in higher socioeconomic (HSE) than in middle (MSE) and lower (LSE) socioeconomic groups (p<0.05). Girls in all age groups had calcium, zinc, iron and vitamin intakes of <50% of Indian recommended dietary intakes. Mean nutrient intakes were significantly higher in HSE than in MSE and LSE girls (p<0.05). Girls with short stature (HAZ <-2) had significantly lower intakes of calcium, zinc, iron, β-carotene, riboflavin, niacin, folate and ascorbic acid (p<0.05). Higher levels of serum zinc and hemoglobin were observed in girls with HAZ >-1 than in short girls even after adjusting for socioeconomic status (SES). The mean serum zinc level of thin girls (BMIZ <-2) was significantly lower than those of both normal and overweight girls after adjusting for SES. Micronutrient sufficiency is of paramount importance for adequate growth in Indian girls.