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Biofortification of Edible Plants: Set the Stage for Better Nutrition

Noureddine Benkeblia

Department of Life Science and Laboratory of Tree Fruit and Aromatic Crop, The Biotechnology Centre, The University of the West Indies, Kingston, Jamaica

Laboratory of Crop Science, Department of Life Sciences, The University of the West Indies, Kingston, Jamaica

1.1 Introduction

The human organism requires a large number of organic and mineral nutrients that are crucial for the growth, development, and the prevention of diseases and disorders. These nutrients, required at relatively high levels - macronutrients - or low to very low levels - micronutrients - are supplied either by our plant or animal food intakes. However, often the daily diet is balanced in calories and quantity, but does not provide the required amount of these nutrients, leading to malnutrition. Consequently, this malnutrition - or nutrients deficiency - can lead to a variety of metabolic and health problems such as digestive problems (Brodeur et al. 1993), skin disorders (Prendiville and Manfredi 1992), stunted or defective bone growth (Branca and Ferrari 2002) . etc.

To compensate these low levels of nutrients in plants, biofortification of edible plants is becoming one the most efficient strategies to overcome malnutrition, and many foods such as cereals, fruits, and vegetables are being fortified with nutrients that are needed to prevent minerals and vitamins deficiencies (Nestel et al. 2006).

From ancient times, agriculture has been the primary source of food and all nutrients for human, and the production systems have been subject to numerous changes to ensure quantitative and qualitative food supplies. With human development, the Industrial Revolution, and then the Green Revolution, food and nutrition turned to agriculture and agro-processing as a primary mean to mitigate, if not eradicating, nutrients deficiencies and malnutrition (Welch 2005). On another hand, the development of novel life science technologies and biofortification of edible plants is regarded as a powerful tool to reduce malnutrition and improve dietary intake of essential minerals and vitamins in staple foods (Figure 1.1). New discoveries in biochemistry and molecular biology have led to incredible development of advanced biotechnology and great promises for improving the output of bioavailable micronutrients from agricultural systems (Welch 2005). However, we need to pragmatically assess whether the biofortification is compatible with the diet diversification and how it might impact agricultural biodiversity for long-term sustainability (Bouis and Welch 2010; Johns and Eyzaguirre 2007).

Figure 1.1 Biofortified crops generated by different approaches: transgenic, agronomic, and breeding. Staple cereals, most common vegetables, beans, and fruits have been targeted by all three approaches. Some crops have been targeted by only one or two approaches depending on its significance and prevalence in the daily human diet.

(From Garg et al. 2018. Open access publication under Creative Commons Attribution License [CC BY] terms with free permission).

This chapter provides a general overview of the different approaches and opportunities for the biofortification of edible plants to achieve the goal of improving human diet and setting the stage for the eradication or alleviation of malnutrition through sustainable agriculture.

1.2 Biofortification and Nutrition

To alleviate nutritional issues and nutrient deficiencies, biofortification of edible plants is considered the most appropriate approach. Modifying dietary customs of the population runs into likely resistance from communities. By contrast, biofortification focuses on improving the nutritional content of region's current agricultural biodiversity, preserving its habits and customs (Johns and Eyzaguirre 2007).

Biofortification of food crops thus has the potential of reaching all the population and communities, particularly rural poor and vulnerable ones with no or limited access to industrially biofortified foods, or where conventional biofortification is difficult or cannot be implemented for technical, economic, or social reasons, and where large quantities of staple rather than nutrition foods crops is consumed.

In recent decades, action has been taken to address malnutrition and micronutrient intakes issues in developing countries. Biofortification technology has been identified as a priority initiative; however, it became evident that this technology might also benefit developed countries consumers as well. Therefore, biofortification became more common in developing countries and evidence of malnutrition mitigation nutrient, bioavailability enhancement and biofortified crops acceptability, are raising more interests. Recent data are showing that 150 different varieties of biofortified crops belonging to 10 different crop species have been released in 30 different countries, of which 27 are developing countries, while 12 other crop species are under evaluation for release in 21 other different countries (Bouis and Saltzman 2017; Bouis et al. 2006; Global Panel 2015). In this regard, many examples can be cited, and some of the studies have confirmed the nutritional value and cost-effectiveness of high-iron bean, orange-flesh sweet potato, cassava, maize, rice, and pearl millet (Global Panel 2015).

Vitamin A deficiency (VAD) is the most prevalent nutrient deficiency in young children in the developing countries, with more than 200 million children under the age five worldwide (WHO 2009). VAD has been rated as the first public health problem in more than 70 countries, and this deficiency affects about 33% of children aged between six months and five years in 2013, with 48% found in sub-Saharan Africa and 44% in South Asia (WHO 2009). In this regard, different studies showed the role of biofortified crops in alleviating VAD deficiency and improving the nutritional status of the population. In developing countries, a study carried out in sub-Saharan Africa showed that the daily vitamin A needs of young children can be covered by the intake of 100?g of orange-fleshed sweet potato (OFSP), a carotenoid-biofortified tuber (Low et al. 2017). Similar observation was noted in Zambia, where inadequate vitamin A intake prevalence was reduced by 3% (Lividini and Fiedler 2015), and diarrhea was reduced by biofortified crops as well (Jones and de Brauw 2015).

Mineral deficiencies are also a major concern, and studies have shown that biofortification might be one of the most cost-effective approaches in alleviating this public health issue (Broadley et al. 2008, 2009). Using Zn-biofortified wheat, valuable increases in Zn absorption have been achieved (Rosado et al. 2009). Feeding two-year-olds with zinc and iron biofortified pearl millet more than adequately enhanced the absorption of both minerals to meet the dietary requirement (Kodkany et al. 2013), and the iron status of schoolchildren (12 to 16 years old) and women fed iron-biofortified beans and pearl millet was significantly improved (Finkelstein et al. 2015; Haas et al. 2016).

Nevertheless, assessment of the efficacy of biofortified foods for enhancing human nutritional status and alleviating malnutrition requires further research in the laboratory, as well as community-based trials. Research should consider the impacts of biofortified crops for larger groups of different gender and age and for long-term consumption (Bouis and Saltzman 2017). Furthermore, additional research is required to assess the nutrients bioavailability of various genotypes of biofortified crops, in particular genetic engineered crops, using different in-vitro and/or in-vivo tests. Additionally, trials need to be carried out to evaluate the agricultural, environmental, and socioeconomic impacts, and these trials must include the communities, the stakeholders, and the policy makers as well (King 2002).

Biofortification of food plants also causes potential alterations of the plants metabolism, and these alterations should be thoroughly assessed beyond the few studies that have already analyzed these alterations. The alteration of these different metabolic pathways might affect growth, development, and productivity of these plants, and it is imperative to determine to what extent these alterations can be minimized or even avoided. However, recent development in omics, particularly metabolomics and related techniques, is significantly contributing to deciphering the potential alterations in plants caused by biofortification (Hall et al. 2008).

1.3 Cultural Practices and Plants Biofortification

Agricultural practices are more likely the simplest and readily most accessible to farmers to overcome the problem of nutrients deficiency of edible plants, and these agronomic-based strategies might be interesting alternative solutions. Indeed, agronomic-based strategies have shown be efficient in improving nutrient contents by many folds. Although the application methods differ, soil fertilization and/or foliar application of fertilizers at different stages of plant growth have shown to increase the nutrients levels of many crops, and fertilization as agronomic strategy for...