Rice Fortification: An Option for Countries with Rampant Folate Deficiency?
A recent study by Htet and co-workers reported on the micronutrient status of adolescent girls in Myanmar. There was good and bad news. On the one hand, less than 1% of the 391 anemic girls had vitamin B12 deficiency. On the other hand, over half the girls had folate deficiency, and most girls had a deficient intake of vitamins A, B6, C, folate, iron and calcium. For folate, none of the girls met folate intake recommendations.
The typical diet in Myanmar contributes to this pattern of deficiency. It is based on rice, and is supplemented by plenty of fish and duck eggs, with vegetables, fruits like banana and guava also consumed daily, and infrequent poultry and red meat consumption. The intake of fish and eggs is probably responsible for the low levels of vitamin B12 deficiency, as vitamin B12 is found exclusively in animal-derived products. Folate is found frequently in legumes, dark green leafy vegetables and organ meats, three food types that did not feature particularly in the diets of these girls. The use of rice as a staple can lead to poor intakes of certain nutrients. Compared to wheat, brown rice has much lower amounts of iron and zinc, and vitamin E, and when white rice is used, the vitamin B1, B2, B3 and B6 content is also lower (data from USDA food database). While both rice and wheat (and other grains) are poor sources of folic acid, the enrichment of wheat flour with folic acid has contributed to improvements in folate status around the world (e.g. see data from Iran, Canada and the US).
Wheat and other cereals that are milled into flour are simple to fortify as the vitamin premix can be added directly to the flour at the end of the milling process and must only be thoroughly mixed. Rice is more difficult to fortify as it is generally consumed as an intact grain, and the practices of washing, frying, soaking and boiling the rice all can reduce the nutrient content of the rice as it is consumed. The Food Fortification Initiative has outlined some methods for fortifying rice grains, and the methods are further expanded in a protocol developed by Ashong et al.. The main methods are (1) Parboiling; (2) Dusting with a micronutrient powder; (3) Coating with micronutrients to form a layer that is difficult to remove by washing; (4) Creating a fortified rice “grain” via extrusion.
Parboiling is one method by which brown rice is soaked in hot water for a few hours to allow the nutrients from the bran to soak through to the endosperm before further processing. Kam, Arcot and Ward recently investigated this technique with respect to folic acid. This method may result in a color change in the rice that may decrease its acceptability.
Dusting is ineffective for most methods of preparing rice as the micronutrient powder is removed by soaking, washing and boiling in excess water, and the nutrient content may be reduced by the high heat of frying the rice grains.
Using a coating of micronutrients on the surface of the grain is effective. Normally, fortified grains are mixed with normal rice grains. Care must be taken that the fortified rice is indistinguishable from the normal rice, or that the consumers are informed about the importance of consuming all the rice regardless of its color.
Rice extrusion uses a dough made from rice that is mixed with micronutrients and extruded to create a fortified rice “grain”. The fortified grains are also mixed with normal rice grains. This process can use broken rice grains, generally an undesirable by-product of rice milling. Although this process is the most expensive, as it requires specialized equipment to produce the rice grains, the micronutrients in the “grain” are most likely to be retained during home preparation (see DSM’s rice fortification backgrounder).
Although more complex than fortifying cereal products use or consumed as a flour, rice fortification is an option for many countries in which rice is a staple food. Perhaps rice fortification can help reduce the iron and folate deficiency that is so common in Myanmar.
Min Kyaw Htet, Umi Fahmida, David I. Thurnham, Lwin Mar Hlaing, Arwin Akib, Budi Utomo and Lisa A. Houghton. Folate and vitamin B12 status and dietary intake of anaemic adolescent schoolgirls in the delta region of Myanmar. British Journal of Nutrition, available on CJO2015. doi:10.1017/S0007114515001609.
Results were part of study NCT01198574
Abdollahi Z, Elmadfa I, Djazayery A, Golalipour MJ, Sadighi J, Salehi F, Sadeghian Sharif S. Efficacy of flour fortification with folic acid in women of childbearing age in Iran. Ann Nutr Metab. 2011;58(3):188-96. doi: 10.1159/000329726. Epub 2011 Jul 9. http://www.ncbi.nlm.nih.gov/pubmed/21757892
Ashong J, Muthayya S, De-Regil LM, Laillou A, Guyondet C, Moench-Pfanner R, Burford BJ, Peña-Rosas JP. Fortification of rice with vitamins and minerals for addressing micronutrient malnutrition (Protocol). Cochrane Database of Systematic Reviews 2012, Issue 6. Art. No.: CD009902. DOI: 10.1002/14651858.CD009902. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD009902/abstract
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DSM. Tackling Hidden Hunger Through Rice Fortification. https://www.dsm.com/content/dam/dsm/cworld/en_US/documents/backgrounder-rice-fortification.pdf
Food Fortification Initiative. Rice Fortification Frequently Asked Questions. http://www.ffinetwork.org/about/faq/faq_rice_industry.html
Kam K, Arcot J, Ward R. 2012. Fortification of rice with folic acid using parboiling technique: Effect of parboiling conditions on nutrient uptake and physical characteristics of milled rice. Journal of Cereal Science, vol. 56, no. 3, pp. 587 - 594, http://dx.doi.org/10.1016/j.jcs.2012.08.010
Shuaibi AM, House JD, Sevenhuysen GP. Folate status of young Canadian women after folic acid fortification of grain products. J Am Diet Assoc. 2008 Dec;108(12):2090-4. doi: 10.1016/j.jada.2008.09.007. http://www.ncbi.nlm.nih.gov/pubmed/19027414