Impact of micronutrient fortification of yoghurt on micronutrient status markers and growth – a randomized double blind controlled trial among school children in Bangladesh

Abstract

BackgroundInterventions providing foods fortified with multiple micronutrients can be a cost-effective and sustainable strategy to improve micronutrient status and physical growth of school children. We evaluated the effect of micronutrient-fortified yoghurt on the biochemical status of important micronutrients (iron, zinc, iodine, vitamin A) as well as growth indicators among school children in Bogra district of Bangladesh.MethodsIn a double-masked randomized controlled trial (RCT) conducted in 4 primary schools, 1010 children from classes 1–4 (age 6–9 years) were randomly allocated to receive either micronutrient fortified yoghurt (FY, n = 501) or non-fortified yoghurt (NFY, n = 509). For one year, children were fed with 60 g yoghurt everyday providing 30% RDA for iron, zinc, iodine and vitamin A. Anthropometric measurements and blood/urine samples were collected at base-, mid- and end-line. All children (FY, n = 278, NFY, n = 293) consenting for the end-line blood sample were included in the present analyses.ResultsBoth groups were comparable at baseline for socio-economic status variables, micronutrient status markers and anthropometry measures. Compliance was similar in both the groups. At baseline 53.4% of the population was anemic; 2.1% was iron deficient (ferritin <15.0 μg/L and TfR > 8.3 mg/L). Children in the FY group showed improvement in Hb (mean difference: 1.5; 95% CI: 0.4-2.5; p = 0.006) as compared to NFY group. Retinol binding protein (mean diff: 0.05; 95% CI: 0.002-0.09; p = 0.04) and iodine levels (mean difference: 39.87; 95% CI: 20.39-59.35; p < 0.001) decreased between base and end-line but the decrease was significantly less in the FY group. Compared to NFY, the FY group had better height gain velocity (mean diff: 0.32; 95% CI: 0.05-0.60; p = 0.02) and height-for-age z-scores (mean diff: 0.18; 95% CI: 0.02-0.33; p = 0.03). There was no difference in weight gain velocity, weight-for-age z-scores or Body Mass Index z-scores.ConclusionIn the absence of iron deficiency at baseline the impact on iron status would not be expected to be observed and hence cannot be evaluated. Improved Hb concentrations in the absence of a change in iron status suggest improved utilization of iron possibly due to vitamin A and zinc availability. Fortification improved height gain without affecting weight gain.Trial registrationClinicalTrial.gov: NCT00980733

Meeting iron needs for infants and children

“…In the study from Bangladesh, there was also an increased height gain velocity in supplemented children but surprisingly no effect on ferritin [42]. The limitation in these multiple micronutrient trials is the possible interaction with other micronutrients.…”

“…The first three also reported an absolute risk reduction of IDA (China: 45-33%, India: 28-13% and Brazil: 75-20%) [39][40][41][42]. All four populations had a high prevalence of anaemia at baseline and all found a significant positive effect on haemoglobin.…”

Practical Application of Linear Growth Measurements in Clinical Research in Low- and Middle-Income Countries

“…For example, urinary lactulose: mannitol and fecal neopterin were correlated with growth rate, expressed as centimeters/month, and corrected for age-related changes [53, 54]. Similarly, height velocity (in cm/year) and HAZ were used as outcome parameters in a study on the impact of micronutrient fortification of yogurt [55], and in a recent Indian study, growth velocity (in cm/month) was associated with maternal height and exclusive breastfeeding [56]. …”

The scale of the evidence base on the health effects of conventional yogurt consumption: findings of a scoping review

“…In addition, the changes in milk constituents that occur during lactic acid fermentation influence the nutritional and physiological value of yogurt (Hewitt and Bancroft, 1985; Bianchi-Salvadori, 1986; Bourlioux and Pochart, 1988; Adolfsson et al, 2004). The efficacy of yogurt has been investigated in relation to a wide range of separate and overlapping outcomes including weight management (Burns et al, 1998), type 2 diabetes (O'Connor et al, 2014), cardiovascular disease risk (Buyuktuncer et al, 2013), bone health (Heaney et al, 2002), dental health (Telgi et al, 2013), the risk of various forms of cancer (Kurahashi et al, 2008), gastrointestinal (GI) health (Pashapour and Iou, 2006; Ballesta et al, 2008), lactose intolerance (Adibi et al, 2009), malnutrition (Sazawal et al, 2013), immunological parameters (Olivares et al, 2006), and overall mortality (Goldbohm et al, 2011). While a range of research designs have been employed to examine the health effects of yogurt, including observational studies (Cramer et al, 1989; Arslantas et al, 2008; Dawczynski and Jahreis, 2009) and experimental studies (Bonjour et al, 2013; Douglas et al, 2013), systematic reviews (and meta-analyses when appropriate) have been conducted in relation to only a few health outcomes (Tong et al, 2011; Aune et al, 2012, 2013; Soedamah-Muthu et al, 2012; Gao et al, 2013; O'sullivan et al, 2013).…”