Potential for increasing the content and bioavailability of Fe, Zn and Ca in plants for human nutrition

Abstract

This paper reviews the possibility and limits for increasing the content and bioavailability of iron (Fe), zinc (Zn) and calcium (Ca) in edible parts of staple crops, such as cereals, pulses, roots and tubers as a way to combat mineral deficiencies in human populations. Theoretically, this could be achieved by increasing the total level of Fe, Zn and Ca in the plant foods, while at the same time increasing the concentration of compounds which promote their uptake (ascorbic acid), and/or by decreasing the concentration of compounds which inhibit their absorption (phytic acid or phenolic compounds). The content of Zn and Ca in grains and fruits can in some cases be increased through soil and/or foliar applications of Zn and Ca fertilisers. Plant breeding and genetic engineering techniques, however, have the greatest potential to increase Fe and Zn content in grains, roots and tubers. The possibility of enhancing Ca and ascorbic acid content in plant foods by plant breeding and genetic engineering remained to be explored. The critical factor is to ensure that the extra minerals have an adequate bioavailability for man. Given the important role of phytic acid and polyphenols in plant physiology, reducing the levels of these compounds in the edible parts of plants does not appear to be wise although introduction of phytases which are active during digestion is an exciting possibility. © 2000 Society of Chemical Industry

Trace Element‐Deficient Soils

“…In fact, it is one of the most abundant elements in the lithosphere (around 5%), primarily in the form of ferromagnesium silicates, and also a major element in most soils, averaging 3-4%. It is included here, because of its importance as a micronutrient and because Fe deficiency is considered the most widespread micro-element malnutrition problem in many crops, animals and human populations throughout the world [6][7][8]12,56,57]. The physiological functions of Fe relate to the ease of this transition element to change valency between þ2 (ferrous Fe) and þ3 (ferric Fe) and its capability to form complexes with many organic and inorganic ligands.…”

Nutritionally relevant elements in staple foods: influence of arable site versus choice of variety

“…On the other hand, nutrient deficiencies (e.g. Fe, Zn, Ca, Mg) are reported not only in developing countries, where cereals and root crops form the main contribution to the diet, but sometimes also in industrialised states (Frossard et al 2000;Elmadfa et al 2003;Pfannhauser et al 2004). Wheat and rye are the most important sources of bread flour, durum wheat is used for the production of noodles, and spring barley may be utilised for the production of beer.…”

Selenium in soils under climate change, implication for human health

“…It is estimated that over 60 % of the world's 6 billion people are iron (Fe) deficient, 30 % are iodine (I) deficient, over 30 % are zinc (Zn) deficient and about 15 % are selenium (Se) deficient (White and Broadley 2009;White et al 2012). In addition, Ca, Cu and Mg deficiencies are common in several developing and developed countries (Frossard et al 2000;Graham 2002, 2005;Rude and Gruber 2004;Grusak and Cakmak 2005;Thacher et al 2006;White and Broadley 2009;White et al 2012). So, in general, these micronutrient deficiencies are a major public health problem affecting more than 30 % of the world's population (more than two billion people suffering from one or more micronutrient deficiencies, WHO 2012) and many public health strategies (like biofortification) exist to reduce or prevent these micronutrient deficiencies.…”