IJERD – International Journal of Environmental and Rural Development (2010) 1–1

Research article
erd

Zinc Deficiency in Agricultural Systems and Its Implication
to Human Health
BASU DEV REGMI
Soil Science and Plant Nutrition, School of Earth and Environment,
The University of Westarn Australia, Perth, Australia
Email: basu.regmi@gmail.com

ZED RENGEL
Soil Science and Plant Nutrition, School of Earth and Environment,
The University of Westarn Australia, Perth, Australia

HOSSEIN KHABAZ-SABERI
Soil Science and Plant Nutrition, School of Earth and Environment,
The University of Westarn Australia, Perth, Australia
Received 30 December 2009

Accepted 5 March 2010

Abstract There are more than 3 billion world population are directly or indirectly affectedwith low zinc (Zn) supply to their food causing up to severe health problems, which isalso linked to Zn deficiency in most agricultural soils world-wide. Agricultural
technologies contribute to improving nutritionally rich food systems, which plays key rolein public health. We therefore review in this paper on the importance of agricultural
systems and its role in human health under Zn deficient situation. Several studies havebeen done to understand the Zn dynamics on crop and plants. There have been much more
efforts given to see agronomic, physiological and molecular aspects of Zn in plants andsoils. It is however, equally important to look at the human consumption perspective forhealthy population. Therefore, this review discusses the role of Zn on soil and crop inview of human nutrition. Agricultural strategies could help to combat such problems inmany ways such as breeding Zn efficient genotypes, application of different Zn fertilizers,
using high Zn content seed for crop production; and seed priming. The content of Zn in
grains and fruits can in some cases be increased through soil or foliar applications of Zn
fertilizers. Level of Zn in plant foods could be achieved either by increasing theconcentration of compounds which promote their uptake like ascorbic acid, or bydecreasing the concentration of compounds which inhibit their absorption of Zn like
phytic acid or phenolic compounds. Low cost and easy approaches such as seed priming
are also effective measures to load higher Zn in edible parts. Plant breeding and genetic
engineering techniques have the greatest potential to increase Zn content in grains, roots
and tubers to combat the Zn deficiency world-wide.
Keywords zinc deficiency, agricultural systems, human nutrition

BACKGROUND
Agricultural technologies can be directed towards improving nutritionally-rich food systems, whichplay an important role in public health. Food systems in many developing countries are now failingto provide adequate quantities of essential nutrients in the people’s diet (Graham and Welch, 1996;
Welch and Graham, 2005). Cropping systems promoted by the green revolution have increased thefood production but also resulted in reduced food-crop diversity and decreased availability of
micronutrients (Welch, 2002; Stein et al., 2007). Micronutrient malnutrition is causing increased
rates of chronic diseases (cancer, heart diseases, stroke, diabetes and osteoporosis) in many

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developing nations; more than 3 billion people are directly affected by the micronutrient
deficiencies (Cakmak et al., 1999; Welch, 2002; WHO, 2002; Welch and Graham, 2004).
Unbalanced use of mineral fertilizers and a decrease in the use of organic manure are the maincauses of the nutrient deficiency in the regions where the cropping intensity is high (Prasad, 1984;
Welch, 1993, 2005). Moreover, agricultural intensification requires an increased nutrient flow
towards and greater uptake of nutrients by crops. Until now, micronutrient deficiency has mostly
been addressed as a soil and, to a smaller extent, plant problem. Currently, it is being addressed as ahuman nutrition problem as well. Increasingly, soils and food systems are affected by
micronutrients disorders, leading to reduced crop production and malnutrition and diseases inhumans and plants (Welch et al., 1982; Welch and Graham, 2004). Conventionally, agriculture istaken as a food-production discipline and was considered a source of human nutrition; hence, inrecent years many efforts (Rengel and Graham, 1995a, b; Cakmak et al., 1999; Frossard et al.,
2000; Welch and Graham, 2005; Stein et al., 2007) have been made to improve the quality of foodfor the growing world population, particularly in the developing nations.
Among the micronutrients, zinc (Zn) is the most important for activity of various enzymes andproper growth and development of plants, animals and humans (Alloway, 2004; Welch andGraham, 2004; Singh et al., 2005). Naturally, plant species differ in capacity to grow at low level ofsoil Zn and to accumulate Zn in the grains. Among different cereal crops, wheat is considered lesstolerant to Zn deficiency stress (exhibits significant yield losses due to Zn deficiency) compared tomore tolerant species such as peas, carrots and rye (Hacisalihoglu and Kochian, 2003). Several
studies (Cakmak et al., 1996; Moussavi-Nik et al., 1997; Erenoglu et al., 1999; Rengel, 1999;
Hacisalihoglu et al., 2001; Gonzalez et al., 2007) have investigated different aspects of Zn uptake
mechanism. This paper aims at evaluating role of agriculture on Zn nutrition for human being andelucidates the strategies potentially help combating Zn deficiency problems in soil-plant-humancontinuum.
ZINC IN SOILS
Zinc deficiency in soils and plants is a global micronutrient deficiency problem reported in many
countries (Sillanpaa, 1982; Graham and Welch, 2000; Alloway, 2004; Singh et al., 2005). Low
availability of Zn in calcareous soils is one of the most widely distributed abiotic stresses in world
agriculture, particularly in Turkey, Australia, China and India (Cakmak et al., 1999; Kenbaev andSade, 2002; Brennan and Bolland, 2006). Zinc deficiency is particularly widespread in cereals
growing on calcareous soils (Graham, 1991; Graham et al., 1992; Cakmak et al., 1997; Genc et al.,2006). Zn deficiency is the most important micronutrient deficiency in wheat (Cakmak et al.. 1998;
Kabata-Pendias. 2001; Alvarez and Gonzalez. 2006; Bagci et al.. 2007), resulting not only in low
production but in the poor nutritional quality of food (Graham and Welch, 1996). In southern
Australia more than 18 million hectares of agricultural land are Zn-deficient (Brennan and Bolland,2006). Similarly, in India alone more than 85 % of the cereal growing area is affected by low Zn.
So, availability of Zn appears to be one of the most limiting factors for quality crop production
worldwide. Zinc deficiency is common on neutral and calcareous soils, intensively cropped soils,
paddy soils and poorly drained soils, sodic and saline soils, peat soils, soils with high available
phosphorus and silicon, sandy soils, highly weathered acid and coarse-textured soils (Cakmak et al.,
1998; Singh et al., 2005). Factors such as topsoil drying, subsoil constraints, disease interactions
and high cost of fertilizer also contribute to zinc deficiency (Sillanpaa, 1982).
ZINC IN PLANTS
Zn is involved in many cellular processes, including activation of enzymes, protein synthesis andmembrane stability, but the knowledge of Zn transport in plants is inadequate (Longnecker andRobson, 1993; Marchner, 1995; Grusak et al., 1999; Rengel, 1999; Alloway, 2004). Plants have anatural ability to extract ions from soil and to distribute them between the roots and the shoot.
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plants (Breckle, 1991). In this context, long-distance root-to-shoot transport in the transpiration
stream via the xylem as well as the transfer from the xylem to the phloem and the retranslocation
via the phloem must be considered as important processes for the redistribution of an element
within a plant (Marschner, 1995). Several studies have demonstrated that Zn is easily transported in
the phloem of wheat (Pearson and Rengel, 1995; Herren and Feller, 1996; Haslett et al., 2001) andthat its redistribution may depend on the plant age and on the Zn content of the source organs(Pearson and Rengel, 1995; Herren and Feller, 1996). Longnecker and Robson (1993) reported thatthe first pool of Zn in plant is seed and this Zn is mobilized to growing seedling. Moussavi-Nik at
al. (1997) also reported that the Zn has a stimulatory effect on crop germination and establishment
as well as the final yield, especially in Zn-deficient soils. Wheat seedlings grown from seed withhigh Zn content produced more tillers and had better growth than seedlings grown from seed with
low Zn content (Rengel and Graham, 1995a,b). Seed loading of Zn is affected by plant species andavailability of Zn to the parent plant (Longnecker and Robson, 1993). Different species loaddifferent amount of Zn into their seeds even when grown in the same environment (Takker et al.,
1988; Longnecker and Robson, 1993; Mozafer, 1993; see review by Rengel et al., 1999).
ZINC IN HUMAN NUTRITION AND HEALTH
It is estimated that about one billion people in the world do not eat sufficient food to meet theirenergy requirements and are consequently undernourished (Stein et al., 2007). Many more people
suffer from ‘hidden hunger’: 150 million are vitamin-A-deficient, almost 2 billion are iodinedeficient, between 4 and 5 billion are iron (Fe) deficient (Hotz and Brown, 2004; Stein et al., 2007)
and about 3 billion are Zn-deficient (WHO, 2002; Hotz and Brown, 2004; Stein et al., 2007). Zinc
acts as a stabiliser of the structures of membranes and cellular components; in human body, mostZn is in the bone and skeletal muscles (Frossard et al., 2000). In addition to its role in enzyme
function (Rivera et al., 1998), Zn also plays a major role in gene expression (Sandstrom, 1997). Zn
deficiency in humans reduces growth, sexual maturity and the immune defense system (Frossard etal., 2000; Cunnigham-Rundles et al., 2005). Few studies (Ninh et al., 1996; Ruz, 1997; Rivera et al.,1998) reported that increased growth in Zn-supplemented infants and preschool children havelowered the incidence of diarrhoea and respiratory infections. Meat and seafood are good sourcesof Zn, and most of the Zn in the developed countries’ diet is provided by animal products (Sanstead,1995). However, in many parts of the developing world, most Zn is provided by cereals andlegume seeds. These plant foods are high in phytic acid, which is a potent inhibitor of Zn
absorption in the human digestive system (Frossard et al., 2000). Among population children andwomen are mostly affected with Zn deficiency (White and Broadley, 2005, Stein et al., 2007).
Given the context of growing world population pressure with limited food supply capacity ofarable lands and cropping systems, the holistic sustainable improvements in the entire food systems
are required to solve the massive problems of malnutrition and increasing chronic diseases indeveloped and especially developing countries (Welch, 2005). The question is how agriculture cancontribute to sustainable solutions to these malnutrition problems. In that context, it is important tounderstand the dynamics of Zn accumulation in grains and other edible parts, which has animplication for human nutrition.
DISCUSSIONS AND CONCLUSION
Primary source of nutrients supply to human being is from crop and livestock products hence.
Agricultural systems have great impact on human health and productivity. Among micronutrients,
Zn is most limiting element for crop and animal productivity. Zinc deficiency is prevalent mostly indeveloping nations, causing the up to severe limitations on physical and intellectual capacity of thepeople as well as adversely affect their health and well-being (Frossard et al., 2000).
Conventionally, public health has been responsible to address the micronutrient malnutrition,rather than agriculture, despite the same underlying cause: an inadequate intake of balanced diet
(Stein et al., 2007). Zinc deficiency has received little public attention, and no systematic© ISERD

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interventions are currently in place to control this micronutrient deficiency (IM 2005 as cited in
Stein et al., 2007). In recent years, efforts have been initiated in agricultural research anddevelopment to increase micronutrients density in edible parts (Cakmak, 2008).
Among different strategies to combat Zn deficiency in soils, application of Zn fertilizers to soil
such as ZnSO4 increases the yield of crops Zn-deficient soils (Yilmaz et al., 1997). It alsosignificantly contributes in increased Zn concentration in cereal grains (Graham et al., 1993,
Rengel et al., 1999). Similarly, foliar application of Zn fertilizers significantly increased the Zn
concentration in seeds (Yilmaz et al., 1997). Harris et al. (2007) found that priming seeds in Zncontaining solutions is a practical way to increase seed Zn prior to sowing and to contribute tobetter seedling growth. Similarly, priming maize seeds in 1% w/v ZnSO4 solution for 16 hsignificantly increased seed Zn concentration, and the seedlings derived from these seeds showed
greater biomass and significantly greater grain yield (Harris et al., 2007 as cited in Cakmak, 2008).
Soil types, growth stage, and genotypes also play key role in efficient use of Zn fertilizers,
therefore those factors to be taken into account while applying fertilizers.
Plant breeding techniques to introduce high Zn traits into high yielding crops anotherpromising approach to load the higher Zn content into edible parts of the crops. Efforts to increase
the micronutrients density into edible parts have been initiated to develop crop genotypes (Cakmak,2008). Similarly, genetic engineering and molecular genetics have great role in agriculturalresearch to identify key regulatory steps in the acquisition of Zn by plants. Identifying andtransferring of the corresponding genes to agriculturally important crops might allow to increase
their nutrient uptake capacity. However, it is important to take into account of diverse soil types
and environments, which have impact on plant growth and development.
Bioavailability of minerals for man is critical because mineral absorption by man from plantfoods is often low. This appears to be mainly due to the presence of phenolic compounds or phyticacid (Fairweather-Tait and Hurrell, 1996 in stein et al., 2007), which is very strong chelator for Zn
and other minerals. Therefore, it is equally important to identifying bioavailability of Zn in plant
products by understanding the presence of other inhibitors like phenolic compound and phytates inedible parts or presence of ascorbic acids (which help in absorption of Zn for human being).
However, with the increased concentration of Zn would help to increase in absorption
proportionately assuming low absorption in the low-Zn plant and high in the high-Zn plant.
CONCLUSION
Agriculture is the mainstay in supplying main sources of nutrition to human being, particularly indeveloping nations. Large number of population are affected with low Zn supply in their food areliving in developing nations, among the most Zn deficient population are children and women. Low
cost and easy approaches such as seed priming, soil and foliar application of Zn fertilizers, areeffective measures to load higher Zn in edible parts. Similarly with less immediate application but
potential approaches are breeding and genetic engineering techniques have the greatest potential toincrease Zn content and reducing phytate and phenolic compounds in edible parts to combat the Zn
deficiency world-wide.
ACKNOWLEDGMENT
Endeavour International Postgraduate Research Scholarship (eIPRS) and University PostgraduateAward International Student (UPA-IS) from The University of Western Australia for Ph.D study of thefirst author is highly acknowledged. Comments from Prof. Dr. Machito Mihara are appreciated while
preparing this manuscript.

REFERENCES
Alloway, B.J. (2004) Zinc in soils and crop nutrition. Online book, 127 (www.zinc/-crops/-org).
© ISERD

101

IJERD – International Journal of Environmental and Rural Development (2010) 1–1

Alvarez, J.M. and Gonzalez, D. (2006) Zinc transformations in neutral soil and zinc efficiency in maize
fertilization. J. Agric. Food Chem., 54, 9488-9495.
Bagci, S.A., Ekiz, H., Yilmaz, A. and Cakmak, I. (2007) Effects of zinc deficiency and drought on grain
yield of field-grown wheat cultivars in Central Anatolia. Journal of Agronomy and Crop Science, 193,
198-206.
Breckle, S. (1991) Growth under stress heavy metals. Plant Roots, The Hidden Half, 351-373, USA.
Cakmak, I. (2008) Enrichment of cereal grains with zinc, Agronomic or genetic biofortification? Plant Soil,
302, 1-17.
Cakmak, I. (2000) Role of zinc in protecting plant cells from reactive oxygen species. New Phytologist, 146,
185-205.
Cakmak, I., Derici, R., Torun, B., Tolay, I., Braun, H.J. and Schlegel, R. (1997) Role of rye chromosomes in
improvement of zinc efficiency in wheat and triticale. Plant and Soil, 196, 249-253.
Cakmak, I., Kalayci, M., Ekiz, H., Braun, H.J., Kilinc, Y. and Yilmaz, A. (1999) Zinc deficiency as apractical problem in plant and human nutrition in Turkey: A NATO-science for stability project. Field
Crops Research, 60, 175-188.
Cakmak, I., Sari, N., Marschner, H., Kalayci, M., Yilmaz, A., Eker, S. and Gulut, K.Y. (1996) Dry matterproduction and distribution of zinc in bread and durum wheat genotypes differing in zinc efficiency.
Plant and Soil, 180(2), 173-181.
Cakmak, I., Torun, B., Erenoglu, B., Ozturk, L., Marschner, H., Kalayci, M., Ekiz, H. and Yilmaz, A. (1998)
Morphological and physiological differences in the response of cereals to zinc deficiency. Euphytica,
100, 349-357.
Cunningham-Rundles, S., McNeeley, D.F. and Moon, A. (2005) Mechanisms of nutrient modulation of theimmune response. J. Allergy Clin. Immun., 115, 1119-1128.
Erenoglu, B., Cakmak, I., Römheld, V., Derici, R. and Rengel, Z. (1999) Uptake of zinc by rye, bread wheat
and durum wheat cultivars differing in zinc efficiency. Plant and Soil, 209, 245-252.
Fairweather-Tait S.J. and Hurrell R.F. (1996) Bioavailability of minerals and trace elements. Nutr. Res. Rev.,9, 295-324.
Frossard, E., Bucher, M., Machler, F., Mozafar, A. and Hurrell, R. (2000) Potential for increasing the content
and bioavailability of Re, Zn and Ca in plants for human nutrition. Journal of the Science of Food andAgriculture, 80, 861-879.
Genc, Y., McDonald, G.K. and Graham, R.D. (2006) Contribution of different mechanisms to zinc efficiency
in bread wheat during early vegetative stage. Plant and Soil, 281, 353-367.
Gonzalez, D., Obrador, A. and Alvarez, J.M. (2007) Behavior of zinc from six organic fertilizers applied to anavy bean crop grown in a calcareous soil. J. Agric. Food Chem., 55, 7084-7092.
Graham, R.D. (1991) Breeding wheats for tolerance to micronutrient deficient soils, Present status andpriorities. Wheat for the non-Traditional Warm Areas, CIMMYT, 315-332, Mexico.
Graham, R.D. and Welch, R.M. (1996) Breeding for staple food crops with high micronutrient density.
Working Papers on Agricultural Strategies for Micronutrients, No.3, International Food Policy ResearchInstitute, USA.
Graham, R.D., Ascher, J.S. and Hynes, S.C. (1992) Selecting zinc-efficient cereal genotypes for soils of low
zinc status. Plant and Soil, 146, 241-250.
Graham, R.D., Ascher, J.S. and Hynes, S.C. (1993) Selecting zinc-efficient cereal genotypes for soils of low
zinc status, Developments in plant and soil sciences. Genetic Aspects of Plant Nutrition, Academic
Press, 349-358, Netherlands.
Grusak, M.A., Pearson, J.N. and Marentes, E. (1999) The physiology of micronutrient homeostasis in field
crops. Field Crops Res., 60, 41-56.
Hacisalihoglu, G. and Kochian, L.V. (2003) How do some plants tolerate low levels of soil zinc?
Mechanisms of zinc efficiency in crop plants. New Phytologist, 159, 341-350.
Harris, D., Rashid, A., Miraj, G., Arif, M. and Shah, H. (2007) On-farm seed priming with zinc sulphate
solution, A cost-effective way to increase the maize yields of resource-poor farmers. Field Crops
Research, 102, 119-127.
Herren, T. and Feller, U. (1996) Effect of locally increased zinc contents on zinc transport from the flag leaf
lamina to the maturing grains of wheat. J. Plant Nutr., 19, 379-387.
Hotz, C. and Brown, K.H. (2004) Assessment of the risk of zinc deficiency in populations and options for its
control. Food Nutr Bull, 25, 94-204.
Kenbaev, B. and Sade, B. (2002) Response of field, Grwon barley cultivars growing on zinc-deficient soils tozinc application. Commun.Soil Sci. Plant Anal., 33(3&4), 533-544.
© ISERD

102

IJERD – International Journal of Environmental and Rural Development (2010) 1–1

Longnecker, N.E. and Robson, A.D. (1993) Distribution and transport of zinc in plants. Zn in Soils andPlants. Kluwer Academic Publishers, 93-106, Netherlands.
Marschner, H. (1995) The soil-root interface (Rhizosphere) in relation to plant nutrition. Chap.15, Mineral
Nutrition of Higher Plants, 2nd Ed, Academic Press.
The Micronutrient Initiative (2005) Controlling vitamin and mineral deficiencies in India, Meeting the goal.
India.
Mozafer, A. (1993) Plant vitamins, Agronomic, physiological, and nutritional aspects. Chapter 5, Plant's
Nutritional Status and Vitamin Content, CRC Press, 157-237, USA.
Ninh, N.X., Thissen, J.P., Collette, G., Khoi, H.H. and Ketelslegers, J.M. (1996) Zinc supplementation
increases growth and circulating insulin-like growth factor I (IGF-I) in growth-retarded Vietnamesechildren. Am. J. Clin. Nutr., 63, 514-519.
Pearson, J.N. and Rengel, Z. (1995) Uptake and distribution of Zn 65 and Mn 54 in wheat growth at
sufficient and deficient level of Zn and Mn. Journal of Experimental Botany, 288, 833-839.
Prasad, A.S. (1984) Discovery and importance of zinc in human nutrition. Fed. Proc., 43, 2829-2834.
Rengel, Z. and Graham, R.D. (1995a) Wheat genotypes differ in Zn efficiency when grown in the chelatebuffered nutrient solution, I, Growth. Plant and Soil, 176, 307-316.
Rengel, Z. and Graham, R.D. (1995b) Wheat genotypes differ in Zn efficiency when grown in chelatebuffered nutrient solution, II, Nutrient uptake. Plant and Soil, 176, 317-324.
Rengel, Z. (1999) Physiological responses of wheat genotypes grown in chelator-buffered nutrient solutions
with increasing concentrations of excess HEDTA. Plant and Soil, 215, 193-202.
Rengel, Z. and Graham, R.D. (1996) Uptake of zinc from chelatebuffered nutrient solutions by wheat
genotypes differing in Zn efficiency. Journal of Experimental Botany, 47, 217-26.
Rengel, Z., Batten, G.D. and Crowley, D.E. (1999) Agronomic approaches for improving the micronutrient
density in edible portions of field crops. Field Crops Res., 60, 27-40.
Rengel, Z., Battenb, G.D. and Crowley, D.E. (1999) Agronomic approaches for improving the micronutrient
density in edible portions of field crops. Field Crops Research, 60, 27-40.
Rivera, J.A., Ruel, M.T., Santizo, M.C., Lonnerdal, B. and Brown, K.H. (1998) Zinc supplementation
improves growth of stunted rural Guatemalan infants. J. Nutr., 128, 556-562.
Ruz, M., Castillo-Duran, C., Lara, X., Codoceo, J., Rebolledo, A. and Atalah, E. (1997) A 14-mo zincsupplementation trial in apparently healthy Chilean preschool children. Am. J. Clin. Nutr., 66, 14061413.
Sandstrom, B. (1997) Bioavailability of zinc. Eur. J. Clin. Nutr., 51, 17-19.
Sanstead, H.H. (1995) Is zinc deficiency a public health problem? Nutrition, 11, 87-92.
Sillanpaa, M. (1982) Micronutrients and the nutrient status of soils, A global study. FAO Soil Bulletin, No.48,
Italy.
Welch, R.M. and Graham, R.D. (2004) Breeding for micronutrients in staple food crops from a humannutrition perspective. Journal of Experimental Botany, 396, 353-364.
Welch, R.M. and Graham, R.D. (2005) Agriculture: the real nexus for enhancing bioavailable micronutrientsin food crops. Journal of Trace Elements in Medicine and Biology. 18, 299-307.
Welch, R.M. (2002) The impact of mineral nutrients in food crops on global human health. Plant and Soil.
247, 83-90.
Welch, R.M. (2005) Harvesting health, Agricultural linkages for improving human nutrition, Micronutreints
in south and south east Asia. ICIMOD/NARC/UoB, 9-16, Nepal.
Welch, R.M. and Graham R.D. (2004) Breeding for micronutrients in staple food crops from a humannutrition perspective. J. Exp. Bot., 55, 353-364.
Welch, R.M., (1993) Zinc concentrations and forms in plants for humans and animals. Zinc in Soil and Plants.
Kluwer Academic Publishers, 183-195, Netherlands.
White, P.J. and Broadley, M.R. (2005) Biofortifying crops with essential mineral elements. Trends Plant Sci.,
12, 586-593.
World Health Organization (2002) The world health report 2002, Reducing risks, Promoting healthy life. UN
Press, USA.
Yilmaz, A., Ekiz, H., Torun, B., GuÈ ltekin, I., Karanlyk, S., Bagcy, S.A. and Cakmak, I. (1997) Different
zinc application methods on grain yield, and zinc concentrations in wheat grown on zinc deficient
calcareous soils in Central Anatolia. J. Plant Nutr., 20, 461-471.

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