Fortification of rice with vitamins and minerals for addressing micronutrient malnutrition.

backgroundRice fortification with vitamins and minerals has the potential to increase the nutrition in rice-consuming countries where micronutrient deficiencies exist. Globally, 490 million metric tonnes of rice are consumed annually. It is the dominant staple food crop of around three billion people.

objectivesTo determine the benefits and harms of rice fortification with vitamins and minerals (iron, vitamin A, zinc or folic acid) on micronutrient status and health-related outcomes in the general population. SEARCH

methodsWe searched CENTRAL, MEDLINE, Embase, CINAHL, and 16 other databases all up to 10 December 2018. We searched ClinicalTrials.gov, and World Health Organization International Clinical Trials Registry Platform (ICTRP) on 10 December 2018. SELECTION CRITERIA: We included randomised and quasi-randomised trials (with either individual or cluster randomisation) and controlled before-and-after studies. Participants were populations older than two years of age (including pregnant women) from any country. The intervention was rice fortified with at least one micronutrient or a combination of several micronutrients (iron, folic acid, zinc, vitamin A or other vitamins and minerals) compared with unfortified rice or no intervention. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. Two review authors independently screened studies and extracted data. MAIN

resultsWe included 17 studies (10,483 participants) and identified two ongoing studies. Twelve included studies were randomised-controlled trials (RCTs), with 2238 participants after adjusting for clustering in two cluster-RCTs, and five were non-randomised studies (NRS) with four controlled before-and-after studies and one cross-sectional study with a control (8245 participants). Four studies were conducted in India, three in Thailand, two in the Philippines, two in Brazil, one each in Bangladesh, Burundi, Cambodia, Indonesia, Mexico and the USA. Two studies involved non-pregnant, non-lactating women and 10 involved pre-school or school-age children. All 17 studies reported fortification with iron. Of these, six studies fortified rice with iron only; 11 studies had other micronutrients added (iron, zinc and vitamin A, and folic acid). One study had one arm each with vitamin A alone and carotenoid alone. Elemental iron content ranged from 0.2 to 112.8 mg/100 g uncooked rice given for a period varying from two weeks to 48 months. Thirteen studies did not clearly describe either sequence generation or allocation concealment. Eleven studies had a low attrition rate. There was no indication of selective reporting in the studies. We considered two RCTs at low overall risk of bias and 10 at high overall risk of bias. One RCT was at high or unclear risk of bias for most of the domains. All controlled before-and-after studies had a high risk or unclear risk of bias in most domains. The included studies were funded by Government, private and non-governmental organisations, along with other academic institutions. The source of funding does not appear to have altered the results. We used the NRS in the qualitative synthesis but we excluded them from the quantitative analysis and review conclusions since they provided mostly contextual information and limited quantitative information. Rice fortified with iron alone or in combination with other micronutrients versus unfortified rice (no micronutrients added) Fortification of rice with iron (alone or in combination with other micronutrients) may make little or no difference in the risk of having anaemia (risk ratio (RR) 0.72, 95% confidence interval (CI) 0.54 to 0.97; I AUTHORS'

conclusionsFortification of rice with iron alone or in combination with other micronutrients may make little or no difference in the risk of having anaemia or presenting iron deficiency and we are uncertain about an increase in mean haemoglobin concentrations in the general population older than 2 years of age. Fortification of rice with iron and other micronutrients such as vitamin A or folic acid may make little or no difference in the risk of having vitamin A deficiency or on the serum folate concentration. There is limited evidence on any adverse effects of rice fortification.