Under the Assessing Food-Based Approaches to Calcium Intakes: Calcium Fortification of Staple Crops project, HarvestPlus conducted research in 2021 to explore food-based approaches to increase calcium intake, with support from the Children’s Investment Fund Foundation (CIFF). As part of this work, HarvestPlus also joined the global Calcium Task Force, led by the New York Academy of Sciences, to guide the global research agenda in this area.
Calcium deficiency is a major global problem. It is estimated that nearly half the world—approximately 3.5 billion people—are at risk because of insufficient calcium in their diets. Calcium’s essential role in building and maintaining strong bones is well-known; it is also needed by muscles for movement, by nerves to shuttle messages between your brain and body, by the cardiovascular system to circulate blood, and by our endocrine system to release hormones. Importantly, it helps lower blood pressure during pregnancy. Preeclampsia and other forms of high blood pressure during pregnancy are among the top three causes of maternal and infant death and illness, particularly in developing countries where 90 percent of the world’s maternal deaths take place.
To investigate ways to address this problem through staple foods, HarvestPlus studied the feasibility of various food-based modalities to increase calcium intake sustainably and cost-effectively via biofortification and post-harvest fortification, including:
- Parboiling rice in Bangladesh
- Nixtamalization (soaking grains in calcium-containing limewater) of maize in Nigeria
- Fortification of whole wheat atta flour in medium-large mills in India
- Food-to-food fortification with wheat and high-calcium finger millet flour blends in India
- Biofortification’s genetic potential and feasibility to deliver added calcium via plant breeding of finger millet, pearl millet, beans, rice, wheat, sweet potato, and other crops
The common goal of these studies was to test whether these technologies could reach fortification levels that could contribute 300-500 mg of calcium (about half the weight of a small paper clip), contributing about 35-60 percent of the daily requirement of women of childbearing age, adolescents, and children who consume these staple foods regularly. Each post-harvest fortification method was studied in terms of its technological requirements, shelf-life, consumer acceptability, and industry readiness to scale each intervention in the respective countries.
In collaboration with the Calcium Task Force, HarvestPlus contributed to the publication of two peer-reviewed papers (linked below) that will be included in a special issue on calcium nutrition in the Annals of the New York Academy of Sciences journal. An informal wheat flour fortification impact assessment team was also convened that included leading calcium researchers from the Institute for Clinical Effectiveness and Health Policy (IECS) in Argentina.
Overall, results were favorable in terms of the calcium concentrations reached in rice, maize, wheat, and finger millet flour and food products, as well as the contribution to the daily calcium requirements which these fortified foods could deliver to vulnerable groups. The potential to breed staple food crops with higher calcium contents using biofortification also yielded promising results: beans, finger millet, and orange sweet potato are candidate crops in breeding for calcium. For children, biofortified versions of these three crops could supply up to 26 percent, up to 68 percent, and more than 100 percent, respectively, of the estimated average daily calcium requirement. For women of childbearing age, these three crops could provide up to 42 percent, up to 87 percent, and more than 100 percent of the estimated daily calcium requirement, respectively.
These encouraging results indicate the promising technical feasibility and opportunities for implementation in the short term that the fortification of wheat flour and parboiled rice offer for the reduction of inadequate dietary calcium intake and the prevention of calcium deficiency and calcium deficiency disorders. However, planning these approaches successfully calls for a phased approach that includes further formative investigation, creating heightened national and state government awareness, and forging public-private partnerships.
- Gomes, Filomena, et al. “Calcium supplementation for the prevention of hypertensive disorders of pregnancy: current evidence and programmatic considerations.” Annals of the New York Academy of Sciences (2022).
- Bourassa, Megan W., et al. “Interventions to improve calcium intake through foods in populations with low intake.” Annals of the New York Academy of Sciences (2021).