Zinc deficient cereals in developing world
September 22nd, 2014 | Qudsia Nazir, Qanita Arshad, Shamsa Kanwal and Sajid Mahmood | No Comments
With the dramatic increase in population of the developing nations, food demand upsurge, thus amplifying the pressure on limited natural resources. Furthermore, malnutrition or inadequate nutrition is an eminent issue of impoverished community.
Pakistan is definitely not in the odds. Micronutrient deficiency is a grim threat because Zinc, Iron and vitamin-A deficiency is substantially reported in developing countries. Zinc deficiency is the fifth largest cause of deaths and disorders in the third world countries. According to WHO, 2.7 billion people, the one-third of worlds population, are ill-fortune to suffer from severe Zinc deficiency. This deficiency is responsible for 16 per cent of respiratory disorders, 10 per cent of diarrhea and 18 per cent malaria yielding 800,000 deaths annually in poverty stricken world. It also affects the immune system, normal reproductive system, normal cell growth, causes skin disorders and cancer.
Zinc is a pivotal micronutrient, not only for plants but also for human beings. It plays a vivid role in DNA replication, protein synthesis, cell division, immune system, in proper development of reproductive system of males and females and neurological functions. It performs as a cofactor in various enzymes. People deficit in Zinc may have to bear hair and memory loss.
Age and gender of a person determine the required dosage, generally it is Zinc 10 mg/day for women and 12 mg/day for men whereas the requirement for pregnant and lactating women is high that is 14. Infants to toddlers require Zinc 3 mg/day while kids ranging 4 to 8 year need 5 mg/day.
Beef, chicken, milk, yogurt, cereals and cheese are rich sources of zinc. Nuts like peanuts, walnuts and almonds also cater Zinc. It is pathetic that poverty stricken nations like Pakistan are incapable to meet requirement due to reliance on cereals for casual diet. Cereals grown on alkaline calcareous soils are deficient in zinc because of various reasons such as more calcium carbonate quantities and little organic matter.
Other causes of low zinc quantities in soils may be due to less zinc in parent material, high soil pH, high phosphorous and salt concentration, water logging, low manure application and fixation of zinc in soil matrix. Some plant factors are also responsible of low zinc availability to humans that are zinc inefficient crop varieties especially cereals while the cereals including wheat, rice and maize are the major source of daily calorie intake in Pakistan thats why people face Zinc scarcity.
Zn bioavailability can be elevated either by escalating the requirement of zinc in the cereal grains or by minifying nutrient binding agents. For an instance a well-known Zinc anti-nutrient is Phytate, which makes complexes with Zn in human intestine thus making it unavailable for human utilization.
Different proportions of minerals are present in particular parts of grains like wheat. Maximal portions of Zinc and other minerals are present in husk, which gets removed in the milling process of wheat grains. Leftover grain contains minute quantities of minerals e.g. Zinc and Iron. 80-85 per cent of carbohydrates and minerals are present in endosperm part of seed with low concentration of Zn and Phytate. Starch and proteins are less affected by crushing process but minerals and vitamin loss is observed by scientists. Therefore, whole grain consumption should be recommended.
Strategies must be developed to eke out the meager Zinc among human race. Purposed strategies could be:
• Supplementation (nutrients as clinical treatment),
• Fortification (addition of an aimed nutrient in food items),
• Food modification (Cooking and processing of food according to nutritional point of view)
“Bio-fortification is a process of enhancing the bioavailable nutrient contents in the edible portion of crops.” It is economical and sustainable strategy to resolve this problem. Question arises here that how can we elevate the concentration of Zinc in cereal grains? Plants are primary producers in food chain, thats why improving the nutrients uptake from the soil by plants will be effective for animals as well as humans.
Zinc bio-fortification can be done by various ways. Genotype selection and improvement can be done by genetic engineering and conventional breeding methods but this is a prolonged method. On the other hand, the fertilizer management is a compelling approach, including soil and foliar application of zinc fertilizers, seed priming, biofertilizers, impregnated fertilizers and management of other interacting nutrients. The use of balanced and integrated nutrition is an effective strategy to increase required element in the edible portion of plants, however economic issues, lack of awareness and unavailability of fertilizers in time are major issues of farmers community to less or no zinc application in soil. Group meetings and field demonstrations are valid scheme to aware farmers about the importance of micronutrients, because it is the need of the hour to use zinc as nutrient. For this purpose the use of fertilizers is the best technique.
Enhancing Zinc contents through fertilizers is an ephemeral solution. The optimum grain Zinc concentration should be 50 ug g-1 of grains dry weight to fulfill human requirements, while the current status is 20-30 ug g-1 of grains dry weight, by proper fertilization in cereals Zinc concentration in grains can be enhanced up to 3 folds. For this purpose organic and inorganic fertilizers alone and in combined form can be used. Numerous Zinc application approach are used to increase Zinc concentration in grains like soil, foliar, soil and foliar, zinc coated urea and Nano-particles application. Nanotechnology is a very effective technique to boost growth, yield and concentration of Zinc in cereal grains due to its small size and more efficiency. So, the use of nanofertilizers can improve plant health by slow and in time release of nutrients.
Hence, we can conclude that zinc bio-fortification in cereal flour is a safe and environmental friendly strategy for overcoming Zinc deficiency in plant and human population of developing world, who consume cereals for their daily caloric intake. Adequate amounts of biofortified cereal flour through agronomic practice (use of fertilizers) can be effective across-the-board. The appropriate level of fortification depends on the population and extent of zinc deficiency in them. The milling process is also critical because a great deal of Zinc is lost in this process. Therefore, it is recommended that whole grain consumption is required to fulfill human zinc requirement.
Published in: Volume 05 Issue 37
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