Fortification of rice with vitamins and minerals for addressing micronutrient malnutrition

BACKGROUND: Rice 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. OBJECTIVES: To 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 METHODS: We 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 RESULTS: = 37%; 4 studies, 927 participants; low-certainty evidence). One study reported that fortification of rice (with folic acid as one of the micronutrients) may improve serum or plasma folate (nmol/L) (MD 4.30, 95% CI 2.00 to 6.60; 215 participants; low-certainty evidence). One study reported that fortification of rice with iron alone or with other micronutrients may slightly increase hookworm infection (RR 1.78, 95% CI 1.18 to 2.70; 785 participants; low-certainty evidence). We are uncertain about the effect of fortified rice on diarrhoea (RR 3.52, 95% CI 0.18 to 67.39; 1 study, 258 participants; very low-certainty evidence). Rice fortified with vitamin A alone or in combination with other micronutrients versus unfortified rice (no micronutrients added) One study had one arm providing fortified rice with vitamin A only versus unfortified rice. Fortification of rice with vitamin A (in combination with other micronutrients) may increase mean haemoglobin (MD 10.00, 95% CI 8.79 to 11.21; 1 study, 74 participants; low-certainty evidence). Rice fortified with vitamin A may slightly improve serum retinol concentration (MD 0.17, 95% CI 0.13 to 0.21; 1 study, 74 participants; low-certainty evidence). No studies contributed data to the comparisons of rice fortification versus no intervention. The studies involving folic acid and zinc also involved iron in the fortification arms and hence we reported them as part of the first comparison. AUTHORS' CONCLUSIONS: Fortification 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.