Print To PDF
Improving Nutrition through Biofortification: From Strategy to Implementation
HarvestPlus, International Food Policy Research Institute, Washington, DC, U.S.A.
1 Senior Specialist, Demand Creation and Business Development, HarvestPlus, International Food Policy Research Institute, 1201 Eye Street NW, Washington, DC 20005, U.S.A. Tel: +1.505.627.4309; E-mail: firstname.lastname@example.org; LinkedIn: www.linkedin.com/in/jenny-walton-225231a
© 2019 AACC International, Inc
Global forecasts predict that by 2050 there will be enough calories produced to feed the global population, but that there will not be enough nutrients to nourish it. A multithemed action plan is necessary to not only ensure that calorie intake is balanced to avoid both stunting and obesity (the double burden), but to ensure that the foods consumed contain enough micronutrients. To date, efforts have been focused on consumer education and encouraging the food industry to reformulate and subsidize access to affordable and nutritious foods. This article presents biofortification (the process of breeding food crops to create crops that are richer in micronutrients) as an evidence-based nutrition strategy for increasing the intake of micronutrients of major concern (e.g., zinc, iron, and vitamin A) through diets in both developed and developing countries. Given that 60% of the calories consumed worldwide are obtained from wheat, rice, or maize food products, more efforts should be made to enhance the micronutrient contents of these staple crops.
According the World Bank, in 2015 10% of the global population lived on less than US$1.90/day. Almost half of the global population (3.4 billion people) struggle to meet their basic needs (29). This is one of the most significant factors leading to 2 billion people (one-quarter of the global population) being affected by vitamin and mineral deficiencies (10). Even for those consumers who have access to the basics necessities of life, such as good schools, health care, electricity, and safe water, and who can also access and afford the components of a health-promoting diet, hidden hunger or malnutrition can still occur. Malnutrition and diet-related death now occur in higher numbers than unsafe sex and alcohol, drug, and tobacco use combined (27).
The micronutrients of most concern are iron, vitamin A, iodine, folate, and zinc (3,10). Nutrient deficiency is responsible for impaired cognitive development, stunting, inability to learn and work, serious sickness, and death. Vitamin A deficiency alone causes 94,500 deaths per year (27). An estimated 250,000–500,000 vitamin A-deficient children become blind every year, and half of these children dye within 12 months of losing their sight (32). The highest rates of vitamin A deficiency are found in sub-Saharan Africa (48%) and South Asia (44%). The World Health Organization (WHO) has classified vitamin A deficiency as a public health problem that affected about one-third of children aged 6–59 months in 2013 (32). Iron deficiency is the most common and widespread nutritional disorder in the world with rates of anemia and underweight for women remaining steady between 2000 and 2016 (10). Anemia affects more than 613 million women of reproductive age worldwide and contributes significantly to maternal deaths (30). Zinc is necessary for optimal immune function, and zinc deficiency is associated with an increased incidence of diarrhea and acute respiratory infections. It is a major cause of death in those younger than 5 years of age. Globally, it is estimated that 17.3% of the population has inadequate zinc intake, with the highest incidence in Africa (23.9%) and Asia (19.4%). Pregnant women and their young children are the groups at the highest risk for zinc deficiency (3). Nutrient deficiency has a direct impact on an individual’s ability to live a healthy, happy, and prosperous life, and malnutrition is not limited to developing countries. Although the effects of malnutrition may be less acute or obvious among more affluent populations, every country on earth is facing a serious issue with malnutrition (10).
Naturally nutritious crops. Biofortification is a pioneering breakthrough that will be part of the solution for one of the world’s biggest problems in the developing world and answer the needs of consumers in the developed world.
The world population, which is currently 7.6 billion, is expected to reach 8.6 billion by 2030, 9.8 billion by 2050, and 11.2 billion by 2100 (24). The global forecast suggests that by 2050, macronutrient availability will be adequate, but that many regions will continue to face critical micronutrient deficiencies (10,18). There will be enough calories produced to feed the global population, but there will not be enough vitamins and minerals to nourish it. To tackle this looming public health epidemic, one of the biggest challenges of our generation, global-scale efforts can be grouped into the following general categories: 1) nutrition education and consumer demand for healthy foods; 2) ensuring and subsidizing access to affordable and nutritious foods; 3) encouraging or legislating food industry reformulation; and 4) utilization of agricultural improvement techniques, including biofortification.
In the past, the agricultural research establishment has prioritized calorie (total food) production over nutrient quality, and in general, yield is the most important factor when breeding a crop or for a farmer choosing seeds to plant. However, this tendency may have inadvertently led to decreasing nutrient density of crops like wheat. Fan et al. (12) reported that concentrations of zinc, iron, copper, and magnesium in wheat remained stable between 1845 and the mid-1960s, but since then have decreased significantly. Overall, the evidence and opinions are mixed (17) or may simply be poorly reported in public health nutrition circles. What can be said is that nutrition factors are rarely a priority in crop breeding, and the food industry in general is not demanding staple ingredients meet micronutrient targets.
Globally there are more than 140,000 species of plants, of which only 150–200 are edible or consumed by humans. Of the calories consumed by humans, 60% are obtained from wheat, maize, and rice (10,26). Is it possible to improve the global food system by increasing the nutrient density of staple grain crops?
Agricultural Improvements through Biofortification
Biofortification is the process of breeding food crops to create crops that are richer in micronutrients, such as vitamin A, zinc, and iron. These crops “biofortify” themselves by loading higher levels of minerals and vitamins in their seeds and roots while they are growing. When eaten, they can provide essential micronutrients that can improve nutrition and public health (14). There are several definitions of biofortification used for different purposes. The U.S. Department of Agriculture (USDA) National Agricultural Library (NAL) Agricultural Thesaurus (NALT) (25) defines biofortification as follows:
An increase in the nutritional value of plant foods obtained through conventional crop breeding methods or through crop genetic engineering techniques. This contrasts with postharvest fortification in which nutrients are added during processing.
WHO (31) defines biofortification as follows:
Biofortification is the process by which the nutritional quality of food crops is improved through agronomic practices, conventional plant breeding, or modern biotechnology. Biofortification differs from conventional fortification in that biofortification aims to increase nutrient levels in crops during plant growth rather than through manual means during processing of the crops. Biofortification may therefore present a way to reach populations where supplementation and conventional fortification activities may be difficult to implement and/or limited.
Codex Alimentarius is currently working on a definition for the purposes of food labeling (9).
HarvestPlus and Biofortification Research Efforts. HarvestPlus is a not-for-profit organization largely funded by UK Aid and the Bill & Melinda Gates Foundation. The organization is part of the International Food Policy Research Institute (IFPRI) and the wider Consultative Group for International Agricultural Research (CGIAR). The 15 CGIAR research centers are independent, nonprofit research organizations that conduct innovative research. Collectively the CGIAR centers employ more than 8,000 scientists, researchers, technicians, and staff. The mission of HarvestPlus is to work with partners to tackle hidden hunger on a global scale by breeding vitamins and minerals into everyday food crops (14). Together, these partners build sustainable food systems and bridge the gap between agriculture and nutrition. Working with the CGIAR centers, HarvestPlus has developed biofortified varieties of staple crops (Table I) that are significantly higher in micronutrients than standard or existing varieties. The technology currently used does not involve genetic modification; only traditional plant breeding methods are utilized. HarvestPlus delivers biofortified crops to subsistence and smallholder farmers through national programs in several of the poorest countries in the world with the highest rates of malnutrition. Twenty-one countries now include biofortification in their national nutrition and agriculture strategies and plans.
Nutrition Evidence on the Public Health Benefits of Biofortification. Biofortified crops improve micronutrient intake and, subsequently, nutrition status. In 2017, the African Journal of Food Agriculture, Nutrition and Development published a special issue devoted to biofortification (19). This issue remains the most current comprehensive review of biofortification, covering the topic from an overview of the landscape and approach for biofortification in Africa, nutrition and food science, crop development and delivery, measuring impact, and public policy. The evidence discussed in the publication indicates that the nutrients provided by biofortification can be bioavailable and result in important improvements in public health outcomes.
There are many published intervention studies in which the effects of biofortification on public health have been evaluated. Use of biofortified crops to tackle micronutrient deficiencies was most recently reviewed by the British Nutrition Foundation and published in the Nutrition Bulletin (15). Although most of the evidence has been gathered in developing countries, biofortification has the potential to positively affect public health in developed countries as well; further modeling and research is required.
Malnutrition is a universal problem that has many forms. It affects most of the world’s population at some point in their life cycle, from infancy to old age. No country is untouched. It affects all geographies, all age groups, rich people and poor people, and all sexes. It is a truly universal problem.
Development Initiatives (10)
Endorsement of Biofortification. At the Chicago Council on Global Affairs 2nd Global Conference on Biofortification in 2014 (2), Akinwumi Adesina, president of the African Development Bank, stated that, “The challenge is no longer the science of biofortification, we know it works; our challenge as policy makers is to scale up biofortified crops to reach millions of households through institutional, regulatory and financial policy.” Adesina is not the only financial leader to endorse the value and impact of biofortification. The Citi Private Bank report published in 2018 recognizes biofortification as a leading innovation that can be used to address the main challenges of today’s food industry (8). The World Bank also recognizes the value of biofortification and advocates that biofortified cereals be the norm, where they are available and agronomically competitive, rather than the exception (28).
Delivering Biofortified Crops
A global value chain approach is required to link all the actors across the biofortified food system. An illustration summarizing the experts and organizations involved in delivering biofortification from agricultural research institutes all the way to the consumer is provided in Figure 1; the method of delivery varies depending on the crop and market dynamics. Currently, biofortification products has been delivered to 33 million people, who are growing and consuming these crops. HarvestPlus teams deliver biofortified crops by working with local private seed companies and farmer organizations of various sizes in-country. Local food businesses are also encouraged to procure biofortified grains or crops for use in the local food industry.
Incentives for Farmers to Grow Biofortified Crops and Consume Products Locally. Biofortified crops are particularly effective vehicles for delivering micronutrients to rural communities, where most of the lower income, smallholder farmers produce staple food crops. These populations often cannot access the formal food system where fortified staples or supplements are more easily available. Very low-income consumers and subsistence-level farmers can rarely afford or have access to the complete complement of foods required to meet nutrient targets. The HarvestPlus business model is targeted toward and built around the needs of the hard-to-reach smallholder farmer. The willingness of farmers to accept new crop varieties will determine whether biofortification can be successfully implemented (23).
The biofortified products that HarvestPlus develops through targeted breeding can meet the nutritional needs and other requirements of smallholder farmers. Agricultural researchers develop crops that are not only economically comparable but competitive for all other traits, such as yield and agricultural inputs. Encouraging farmers to grow biofortified crops, by switching from their traditional seed or vine sources to biofortified varieties, is where HarvestPlus invested its time and expertise in the early phase of national programs. HarvestPlus and many other research groups have evaluated the drivers behind farmer choices, seeking to develop and offer desirable biofortified options. Today, worldwide there are approximately 33 million people who grow and consume biofortified crops (13).
To assist product (crop) development, the willingness of farmers to grow biofortified crops has been extensively researched. This willingness has also been investigated through farmer field-day evaluations, monitoring surveys, and adoption studies, as well as impact evaluation studies (20). Partnering with agricultural input suppliers, farmer organizations, and seed and vine sellers is an essential support mechanism for farmers. Key requirements and drivers for adoption of biofortified crops by smallholder farmers are
- Cost of inputs are the same; if they are higher, the return on investment must be obvious.
- Access to market—guaranteed buyer for surplus crop.
- Confidence in the product and product information—knowledge of yield, agricultural inputs, farmer training.
- Nutritional benefits.
- Taste and enjoyment for in-home, family consumption.
Incentives for the Food Industry to Adopt Biofortification, Expanding Market Access for Farmers. For biofortification to be self-sustaining, it must be fully embedded in the global food system. Forging the right partnerships with the food industry is an essential component of sustainable success. Through work commissioned and supported by the U.K. Department for International Development (DFID), HarvestPlus interviewed nearly 100 businesses and 250 individuals about their experiences and requirements for biofortified products. Businesses included farmer organizations, seed sellers, food processors, and marketers—from farm-gate vendors to multinational global food brands. The interviews revealed that, although high demand exists, there are several issues holding back the scaling up of biofortified crops into the food system. A summary of these issues is provided in Table II.
It is essential to detail a value proposition for each crop and to not tackle biofortification as a generic tool for the food industry. Biofortified crops such as wheat and rice are ideal for quietly improving the food system, as current nutrient levels in biofortified crops do not allow for health claims, except for large food portions. Although consumers will not know they are eating more nutritious foods, the higher micronutrient levels will improve their general health and help them avoid malnutrition. Many global businesses have already committed to improving the food system through initiatives, such as the World Business Council for Sustainable Development project Food Reform for Sustainability and Health (FReSH). The Access to Nutrition Index: Global Index 2018 commended 12 companies that shared evidence of their investments in research or other areas of the business to develop solutions to undernutrition; this was double the number of companies referenced in the 2016 report. Nestlé’s example of the use of high-vitamin A orange maize was cited as a leading practice (1).
Biofortified crop varieties have great potential for use in innovative food products, with crops such as yellow cassava and orange maize providing visual innovation with traditional staple crops. In general, crops biofortified with iron have the most commercial potential (i.e., health claims). High-iron pearl millet and high-iron beans bring food and nutrition information to the store shelf that can be communicated to the consumer as compelling comparative nutrition and health claims for these naturally rich sources of iron.
HarvestPlus has more than 120 partnerships and working arrangements with commercial organizations using biofortified products and foods in their supply chains. The possible applications that biofortification can bring to the food industry are limitless: there is room for both industry commitments to improve the food system and commercially discernible characteristics that individual food businesses can own and use to stand out on crowded supermarket shelves. Crop breeding targets are being met and exceeded on a regular basis, and in the future, all staple crops could be able to carry nutrient content claims. HarvestPlus continues to engage with and listen to global actors in the food industry through multi-stakeholder events, such as the workshop held in London in 2018 (16).
Encouraging Consumers to Purchase Biofortified Products. In 2018, in the United States alone, the naturally healthy packaged food market was valued at US$22,201.9 million (11). The global health and wellness food market was valued at US$707.12 billion in 2016 and is projected to increase to US$811.82 billion by 2021 (21). Biofortification fits into this growing consumer health trend in both developed and developing markets. The consumer drivers behind this trend were explored in the DFID-funded consumer research performed by Leatherhead Food Research described in the 2017 unpublished report “Attitudes to Using Bio-fortified Crops in Manufactured Products.” The report notes that consumers are open to manufacturers using higher nutrient plants and grains in products and that intrinsic nutrition is preferred to adding nutrients or fortifying products (the report is available from HarvestPlus upon request).
Consumer acceptance in developing countries has also been evaluated. Sensory evaluations (e.g., appearance, taste, and texture) and willingness-to-pay studies have been conducted to understand consumer acceptance of biofortified foods (4). Sensory evaluation studies conducted in Uganda, Tanzania, Mozambique, and South Africa showed that consumers liked the sensory attributes of biofortified high-vitamin A orange sweet potato, as well as those of various products made with the biofortified orange sweet potato, such as bread (7). Studies in rural Uganda revealed that when nutrition information on the benefits of high-vitamin A orange sweet potato was provided, consumers valued vitamin A-rich orange varieties more than white varieties (4). Collectively, these studies highlight the importance of information campaigns in driving demand for biofortified orange sweet potato.
In a 2017 systematic review (23), in which sweet potato and maize were the most studied crops, the authors concluded that, “Overall, sensory acceptance was good, and availability and information on health benefits of the crops were the most important determinants of acceptance and adoption.” Bouis and Saltzman (5) state, “Biofortification is a feasible and cost-effective means of delivering micronutrients to populations that may have limited access to diverse diets and other micronutrient interventions.” Whether consumers live in the United Kingdom or Kenya, the key requirements and drivers for food purchases are price, taste, nutrition, and social responsibility or ethical purchasing. Research shows consumers will embrace biofortified foods because of their micronutrient content; they do not necessarily need to know why or how biofortification is accomplished.
The Future of Biofortification
The HarvestPlus program began in 1993, and with funding from the U.S. Agency for International Development (USAID), Howarth “Howdy” Bouis took his ideas to crop breeders at nine CGIAR centers. Since then, with major support from the Bill & Melinda Gates Foundation and UK AID, HarvestPlus has reached 33 million people. How will it achieve its goal of reaching 1 billion people with biofortified crops by 2030? Efforts to date have followed a bottom-up approach of working with smallholder famers in communities that are suffering the most. While this work continues, biofortification should become more widely available or “mainstreamed” into all crop breeding targets. CGIAR (6) has devised a five year biofortification strategy for 2019 to 2023, outlining a strategy for how biofortification of crops with minerals will be “mainstreamed” into all breeding programs. The micronutrient contents of crops should be a key component of future crop development. It is important that leading food manufacturers also have the capacity to demand improvements in the staple foods they purchase and can actively improve the nutrients delivered through the food system. HarvestPlus will lead work in this area, finding the incentives the food industry requires to take biofortification from a publicly funded nutrition intervention to a sustainable, commercially driven value addition to the food industry. If the food industry demands biofortification, then farmers at all scales will adopt biofortified crops into their standard farming practices. Biofortification is positioned to be the most innovative and profitable nutrition improvement the food industry has seen to date.
Jenny Walton is the, senior specialist, demand creation and business development at HarvestPlus. Jenny is an accomplished professional in the responsible promotion and commercialization of food and nutrition. Jenny is a registered nutritionist with 20 years of experience working in the food industry for well-known brands such as the Co-op, Danone, United Biscuits, and Kellogg’s. She has worked in various nutrition-related roles, including food policy, nutrition science, food regulations, nutrition communications, and marketing. Now based with the HarvestPlus global team, Jenny’s role at HarvestPlus is to establish ways to scale up the use and reach of biofortified foods via partnerships across the value chain. Working with the private sector, her objective is to find the incentives to commercialize biofortification and work in partnership to overcome the barriers to scale. LinkedIn: www.linkedin.com/in/jenny-walton-225231a
- Access to Nutrition Foundation. Access to Nutrition Index: Global Index 2018. Published online at www.accesstonutrition.org/sites/gl18.atnindex.org/files/resources/atni_report_global_index_2018.pdf. ATNF, Utrecht, Netherlands, 2018.
- Adesina, A. Dr. Akinwumi Adesina’s speech on biofortification. Published online at www.thechicagocouncil.org/blog/global-food-thought/dr-akinwumi-adesinas-speech-biofortification. Chicago Council on Global Affairs, Chicago, IL, 2014.
- Bailey, R. L., West, K. P., Jr., and Black, R. E. The epidemiology of global micronutrient deficiencies. Ann. Nutr. Metab. 66(Suppl. 2):22, 2015.
- Birol, E., Meenakshi, J. V., Oparinde, A., Perez. S., and Tomlins, K. Developing country consumers’ acceptance of biofortified foods: A synthesis. Food Secur. 7:555, 2015.
- Bouis, H. E., and Saltzman, A. Improving nutrition through biofortification: A review of evidence from HarvestPlus, 2003 through 2016. Global Food Secur. 12:49, 2017.
- CGIAR. CGIAR Five-year biofortification strategy 2019-2023. Published online at www.cgiar.org/wp/wp-content/uploads/2018/09/SMB10-BP1b-%E2%80%93-Biofortification-Strategy.pdf. CGIAR, Montpellier, France, 2018.
- Chowdhury, S., Meenakshi, J. V., Tomlins, K. I., and Owori, C. Are consumers in developing countries willing to pay more for micronutrient-dense biofortified foods? Evidence from a field experiment in Uganda. Am. J. Agric. Econ. 93:83, 2011.
- Citi Private Bank. Citi GPS: Feeding the future. Published online at www.privatebank.citibank.com/home/fresh-insight/citi-gps-feeding-the-future.html. Citigroup, New York, NY, 2018.
- Codex Alimentarius Commission. Joint FAO/WHO Food Standards Programme. Codex Committee on Nutrition and Foods for Special Dietary Uses report. Proposed draft definition for biofortification. Rep. CX/NFSDU 17/39/5. Published online at www.fao.org/fao-who-codexalimentarius/sh-proxy/en/?lnk=1&url=https%253A%252F%252Fworkspace.fao.org%252Fsites%252Fcodex%252FMeetings%252FCX-720-39%252Fnf39_05e.pdf. FAO, Rome, 2017.
- Development Initiatives. 2018 Global Nutrition Report: Shining a light to spur action on nutrition. Published online at https://globalnutritionreport.org/reports/global-nutrition-report-2018. Development Initiatives Poverty Research Ltd., Bristol, UK, 2018.
- Euromonitor International. Naturally healthy packaged food in the USA: USA market 2018 report. Euromonitor International, London, U.K., 2018.
- Fan, M. S., Zhao, F. J., Fairweather-Tait, S. J., Poulton, P. R., Dunham, S. J., and McGrath, S. P. Evidence of decreasing mineral density in wheat grain over the last 160 years. J. Trace Elem. Med. Biol. 22:315, 2008.
- HarvestPlus. Celebrating our partners with the 2017 annual report. Published online at www.harvestplus.org/knowledge-market/in-the-news/celebrating-our-partners-2017-annual-report. HarvestPlus, Washington, DC, 2018.
- HarvestPlus. Our history. Published online at www.harvestplus.org/about/our-history. HarvestPlus, Washington, DC, 2018.
- Lockyer, S., White, A., and Buttriss, J. L. Biofortified crops for tackling micronutrient deficiencies—What impact are these having in developing countries and could they be of relevance within Europe? Nutr. Bull. 43:319, 2018.
- Lockyer, S., White, A., Walton, J., and Buttriss, J. L. Proceedings of the ‘Working Together to Consider the Role of Biofortification in the Global Food Chain’ workshop. Nutr. Bull. 43:416, 2018.
- Marles, R. J. Mineral nutrient composition of vegetables, fruits and grains: The context of reports of apparent historical declines. J. Food Compos. Anal. 56:93, 2017.
- Nelson, G., Bogard, J., Lividini, K., Arsenault, J., Riley, M., et al. Income growth and climate change effects on global nutrition security to mid-century. Nat. Sustain. 1:773, 2018.
- Oniang’o, R., ed. Special issue devoted to biofortification. Afr. J. Food Agric. Nutr. Dev. Published online at www.ajfand.net/Volume17/No2/index.html. 2017.
- Saltzman, A., Birol, E., Oparinde, A., Andersson, M. S., Asare-Marfo, D., Diressie, M. T., Gonzalez, C., Lividini, K., Moursi, M., and Zeller, M. Availability, production, and consumption of crops biofortified by plant breeding: Current evidence and future potential. Ann. N. Y. Acad. Sci. 1390:104, 2017.
- Statistica. Health and wellness food market value worldwide from 2016 to 2021 (in billion U.S. dollars). Accessed online at www.statista.com/statistics/502267/global-health-and-wellness-food-market-value. Statistica, New York, NY, 2019.
- Suwarno, W. B., Hannok, P., Palacios-Rojas, N., Windham, G., Crossa, J., and Pixley, K. V. Provitamin A carotenoids in grain reduce aflatoxin contamination of maize while combating vitamin A deficiency. Front. Plant Sci. DOI: https://doi.org/10.3389/fpls.2019.00030. 2019.
- Talsma, E. F., Melse-Boonstra, A., and Brouwer, I. D. Acceptance and adoption of biofortified crops in low- and middle-income countries: A systematic review. Nutr. Rev. 75:798, 2017.
- United Nations Department of Economic and Social Affairs. The 2017 revision of world population prospects. Published online at https://population.un.org/wpp. UN DESA Population Division, New York NY, 2017.
- U.S. Department of Agriculture National Agricultural Library, Inter-American Institute for Cooperation on Agriculture, and Alliance of Agricultural Information and Documentation Services of the Americas. Agricultural Thesaurus and Glossary. Published online at https://data.nal.usda.gov/dataset/nal-agricultural-thesaurus-and-glossary. USDA Agricultural Research Service, Beltsville, MD, 2019.
- U.S. Department of Agriculture and U.S. Department of Health and Human Services. Scientific Report of the 2015 Dietary Guidelines Advisory Committee. Published online at http://health.gov/dietaryguidelines/2015-scientific-report/pdfs/scientific-report-of-the-2015-dietary-guidelines-advisory-committee.pdf. U.S. Government Printing Office, Washington, DC, 2015.
- Willett, W., Rockström, J., Loken, B., Springmann, M., Lang, T., et al. Food in the Anthropocene: The EAT-Lancet Commission on healthy diets from sustainable food systems. Lancet. DOI: https://doi.org/10.1016/S0140-6736(18)31788-4. 2019.
- World Bank. An overview of links between obesity and food systems: Implications for the food and agriculture global practice agenda. Published online at http://documents.worldbank.org/curated/en/222101499437276873/pdf/117200-REVISED-WP-Obesity-Overview-Web-PUBLIC-002.pdf. World Bank Group, Washington, DC, 2017.
- World Bank. Understanding poverty: Overview. Published online at www.worldbank.org/en/topic/poverty/overview. World Bank Group, Washington, DC, 2019.
- World Health Organization. Global nutrition targets 2025: Anaemia policy brief. Published online at www.who.int/nutrition/publications/globaltargets2025_policybrief_anaemia. WHO, Geneva, Switzerland, 2014.
- World Health Organization. Biofortification of staple crops. Published online at www.who.int/elena/titles/biofortification. WHO, Geneva, Switzerland, 2019.
- World Health Organization. Micronutrient deficiencies: Vitamin A deficiency. Published online at www.who.int/nutrition/topics/vad. WHO, Geneva, Switzerland, 2019.