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 it's 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

Reply to SA Tanumihardjo et al.

ISSN:0002-9165ISSN:1938-320

Correlations of the constructs using the combined health belief and theory of planned behavior models.

<p>(Adjusted model based on Sun et al 2006) *P<0.05, ** P<0.001 (both two tailed) The model: The model is based on the idea that the construct Behavioral intention (intention to feed child with pro-vitamin A rich cassava) is an important predictor for Behavior (feeding the child pro-vitamin A rich cassava) The constructs related to ‘Background and perception’, are ‘Knowledge’ (about pro-vitamin A rich cassava and VAD), Perceived susceptibility' (perception of developing VAD), ‘Perceived severity’ (notion of seriousness of developing VAD), and ‘Health value’ (notion of priority to stay healthy). The constructs related to ‘Beliefs and attitudes’, are ‘Health behavior identity’ (notion that it is good to eat vitamin A pro-vitamin A rich cassava), ‘Perceived barriers’ (perceived obstacles which prevent the consumer from eating pro-vitamin A rich cassava) and ‘Attitude towards behavior’ (positive or negative feeling towards eating pro-vitamin A rich cassava). The external factors consist of the constructs ‘Subjective norms‘ (perceived social pressure to consume pro-vitamin A rich cassava), ‘Control beliefs (perceived ability to consume pro-vitamin A rich cassava), and ‘Cues to action’ (external triggers, which stimulate to consume pro-vitamin A rich cassava).</p

Results for the difference test with pro-vitamin A rich and white cassava.

*<p> =  significant (α = 0.05) using Tarone's Z statistic.</p>**<p> =  significant (α = 0.05).</p

Results for the preference test with pro-vitamin A rich and white cassava.

*<p> =  significant (α = 0.05).</p

Predictors of ‘Health behavior identity’ (model 1) to consume pro-vitamin A rich cassava among the study population (n = 140).

*<p>All models were adjusted for interviewer, age and education of the caretaker.</p