Zinc deficiency
Encyclopedia
Zinc deficiency is insufficient zinc
to meet the needs of biological organisms. It can occur in both plants and animals. Zinc deficient soil
is soil in which there is insufficient zinc to allow plants to grow normally.
needs.
Conservative estimates suggest that 25% of the world's population is at risk of zinc deficiency.
, diarrhea
, acrodermatitis enteropathica
, chronic
liver disease
, chronic renal disease, sickle-cell disease
, diabetes, malignancy, and other chronic illness
es. It can also occur after bariatric surgery
.
Zinc deficiency is typically the result of inadequate dietary intake of zinc, disease states that promote zinc losses, or physiological states that require increased zinc. Populations that consume primarily plant based diets that are low in bioavailable zinc often have zinc deficiencies. Diseases or conditions that involve intestinal malabsorption promote zinc losses. Fecal losses of zinc caused by diarrhea are one contributing factor, often common in developing countries. Changes in intestinal tract absorbability and permeability due, in part, to viral, protozoal, and bacteria pathogens may also encourage fecal losses of zinc. Physiological states that require increased zinc include periods of growth in infants and children as well as in mothers during pregnancy.
lesions, diarrhea
, and wasting of body tissues. A lack of zinc can contribute to acne
. Eyesight, taste, smell and memory are also connected with zinc. A deficiency in zinc can cause malfunctions of these organs and functions. Congenital abnormalities causing zinc deficiency may lead to a disease called acrodermatitis enteropathica
.
One easily recognized sign which may be caused by zinc deficiency is white spots, bands, or lines on fingernails (leukonychia
). An occasional white spot is usually evidence that the immune system overcame a bacterial or some other systemic infection, and is a positive, not negative sign. Some women may have multiple parallel white bands or lines on the fingernails marking menstrual cycles when marginal zinc deficiency was present.
which can degenerate into anorexia
or anorexia nervosa
. Appetite disorders, in turn, cause malnutrition
and, notably, inadequate zinc intake. Anorexia itself is a cause of zinc deficiency, thus leading to a vicious cycle: the worsening of anorexia worsens the zinc deficiency. The use of zinc in the treatment of anorexia has been advocated since 1979 by Bakan. At least 15 trials showed that zinc improved weight gain in anorexia. A 1994 randomized, double-blind, placebo-controlled trial showed that zinc (14 mg per day) doubled the rate of body mass increase in the treatment of anorexia nervosa (AN).
Deficiency of other nutrients such as tyrosine
and tryptophan
(precursors of the monoamine neurotransmitter
s norepinephrine
and serotonin
, respectively), as well as vitamin B1 (thiamine
) could contribute to this phenomenon of malnutrition-induced malnutrition.
, rats who were deprived of zinc during early fetal development exhibited increased emotionality, poor memory, and abnormal response to stress which interfered with performance in learning situations. Zinc deprivation in monkeys showed that zinc deficient animals were emotionally less mature, and also had cognitive deficits indicated by their difficulty in retaining previously learned problems and in learning new problems. Human observational studies show weaker results. Low maternal zinc status has been associated with less attention during the neonatal period and worse motor functioning. In some studies, supplementation has been associated with motor development in very low birth weight
infants and more vigorous and functional activity in infants and toddlers.
recommendation for diarrhea control includes the use of 20 mg per day of zinc supplementation for 10 to 14 days (10 mg per day for infants under the age of six months). A zinc taste test may have potential for diagnosing deficiency.
and placental abruption has been documented in zinc deficient animals. These effects may be mediated by the defective functioning of estrogen via the estrogen receptor, which contains a zinc finger protein. A review of pregnancy outcomes in women with acrodermatitis enteropathica, reported that out of every seven pregnancies, there was one abortion and two malfunctions, suggesting the human fetus is also susceptible to the teratogenic effects of severe zinc deficiency. However, a review on zinc supplementation trials during pregnancy did not report a significant effect of zinc supplementation on neonatal survival.
levels. There is evidence that the way zinc influences hunger depends on the sodium
/osmotic status of the organism, with low sodium/low zinc levels increasing hunger and high sodium/low zinc levels decreasing it. An organism with a low level of zinc has an increased susceptibility to hypoosmotic stress and cell rupture. Thus if the osmotic pressure is too low the organism may be inclined to eat to raise osmolality and prevent osmotic shock
. It should be noted that zinc is known to affect osmolality by increasing sodium retention.
In rats, the "first visible sign" of zinc deficiency is a decreased appetite.
To combat zinc deficiency, five intervention strategies can be used:
These five intervention strategies may be used individually or in combination, depending on the setting, target group and degree of zinc deficiency.
The amount of zinc absorbed by the human body is a function of dietary intake of both zinc and phytate
(a phosphate storage compound that chelates
zinc), because the ratio between these two substances affects the bioavailability of zinc. Meeting the needs for absorbed zinc requires an increase in the zinc content and/or a decrease in the phytate content.
Many agricultural countries around the world are affected by zinc deficiencies.
In China, zinc deficiency occurs on around half of the agricultural soils, affecting mainly rice and maize.
In India, zinc-deficient soils occupy almost 50% of the agricultural area and are a critical constraint on yield, but crops are highly responsive to zinc fertilization.
In Turkey, major yield and quality benefits in wheat have been obtained with the widespread use of zinc fertilizers, where half of the cereal growing land is zinc-deficient.
Research has shown that areas with zinc-deficient soils are often regions with widespread zinc deficiency in humans.
A basic knowledge of the dynamics of Zn in soils, understanding of the uptake and transport of Zn in plant systems and characterizing the response of plants to Zn deficiency are essential steps in achieving sustainable solutions to the problem of Zn deficiency in plants and humans (Zinc in soils and crop nutrition), International Fertilizer Industry Association (IFA)and International Zinc Association (IZA).)
Where zinc deficiency is a limiting factor, zinc fertilization can increase crop yields. Balanced crop nutrition supplying all essential nutrients, including zinc, is a cost effective management strategy. Even with zinc-efficient varieties, zinc fertilizers are needed when the available zinc in the topsoil becomes depleted.
Plant breeding, including modern biotechnology, can improve:
Zinc uptake capacity of plants under soil conditions with low chemical availability of zinc;
Zinc translocation, thus elevating zinc content in edible crop parts rather than the rest of the plant;
Zinc bioavailability.
For optimal efficiency, zinc-efficient genotypes should be associated with complementary soil crop management (including fertilization) to ensure adequate zinc uptake by roots and thus enhance zinc nutrition of crops and humans
Through a partnership with Cukurova University, the State and the private company TOROS Agri Industry Group, zinc was added to fertilizers. While the product was initially made available at the same cost, the results were so convincing that Turkish farmers significantly increased the use of the zinc-fortified fertilizer (1 per cent of zinc) within a few short years, despite the repricing of the products to reflect the added value of the content.
Today, nearly 10 years after the identification of the zinc deficiency problem, the total amount of zinc-containing compound fertilizers produced and applied in Turkey reached a record level of 300,000 tonnes per annum. It is estimated that the economic benefits associated with the application of Zn-fertilizers on Zn deficient soils in Turkey is around US$ 100 million per year. Zinc deficiency in children has been dramatically reduced.
Such a policy could be easily replicated around the world in the many zinc-deficient countries.
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
to meet the needs of biological organisms. It can occur in both plants and animals. Zinc deficient soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
is soil in which there is insufficient zinc to allow plants to grow normally.
Description
Hypozincemia is a condition where insufficient zinc is available for metabolicMetabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
needs.
Prevalence
In fact, one-third of the world population is at risk of zinc deficiency, ranging from 4 to 73% depending on the country. Zinc deficiency is the fifth leading risk factor for disease in the developing world. Providing micronutrients, including zinc, to humans is one of the four quick-win solutions to major global problems identified in the Copenhagen Consensus from an international panel of distinguished economists.Conservative estimates suggest that 25% of the world's population is at risk of zinc deficiency.
Causes
Hypozincemia is usually a nutritional deficiency, but can also be associated with malabsorptionMalabsorption
Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal tract.Impairment can be of single or multiple nutrients depending on the abnormality...
, diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
, acrodermatitis enteropathica
Acrodermatitis enteropathica
Acrodermatitis enteropathica is an autosomal recessive metabolic disorder affecting the uptake of zinc, characterized by periorificial and acral dermatitis, alopecia , and diarrhea....
, chronic
Chronic (medicine)
A chronic disease is a disease or other human health condition that is persistent or long-lasting in nature. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include asthma, cancer, diabetes and HIV/AIDS.In medicine, the...
liver disease
Liver disease
Liver disease is a broad term describing any single number of diseases affecting the liver.-Diseases:* Hepatitis, inflammation of the liver, caused mainly by various viruses but also by some poisons , autoimmunity or hereditary conditions...
, chronic renal disease, sickle-cell disease
Sickle-cell disease
Sickle-cell disease , or sickle-cell anaemia or drepanocytosis, is an autosomal recessive genetic blood disorder with overdominance, characterized by red blood cells that assume an abnormal, rigid, sickle shape. Sickling decreases the cells' flexibility and results in a risk of various...
, diabetes, malignancy, and other chronic illness
Illness
Illness is a state of poor health. Illness is sometimes considered another word for disease. Others maintain that fine distinctions exist...
es. It can also occur after bariatric surgery
Bariatric surgery
Bariatric surgery includes a variety of procedures performed on people who are obese. Weight loss is achieved by reducing the size of the stomach with an implanted medical device or through removal of a portion of the stomach or by resecting and re-routing the small intestines...
.
Zinc deficiency is typically the result of inadequate dietary intake of zinc, disease states that promote zinc losses, or physiological states that require increased zinc. Populations that consume primarily plant based diets that are low in bioavailable zinc often have zinc deficiencies. Diseases or conditions that involve intestinal malabsorption promote zinc losses. Fecal losses of zinc caused by diarrhea are one contributing factor, often common in developing countries. Changes in intestinal tract absorbability and permeability due, in part, to viral, protozoal, and bacteria pathogens may also encourage fecal losses of zinc. Physiological states that require increased zinc include periods of growth in infants and children as well as in mothers during pregnancy.
Signs and symptoms
Signs of zinc deficiency include hair loss, skinSkin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
lesions, diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
, and wasting of body tissues. A lack of zinc can contribute to acne
Acne
Acne is a general term used for acneiform eruptions. It is usually used as a synonym for acne vulgaris, but may also refer to:*Acne aestivalis*Acne conglobata*Acne cosmetica*Acne fulminans*Acne keloidalis nuchae*Acne mechanica...
. Eyesight, taste, smell and memory are also connected with zinc. A deficiency in zinc can cause malfunctions of these organs and functions. Congenital abnormalities causing zinc deficiency may lead to a disease called acrodermatitis enteropathica
Acrodermatitis enteropathica
Acrodermatitis enteropathica is an autosomal recessive metabolic disorder affecting the uptake of zinc, characterized by periorificial and acral dermatitis, alopecia , and diarrhea....
.
One easily recognized sign which may be caused by zinc deficiency is white spots, bands, or lines on fingernails (leukonychia
Leukonychia
Leukonychia , also known as white nails, is a medical term for white discoloration appearing on nails. It is derived from the Greek words leuko and onyx...
). An occasional white spot is usually evidence that the immune system overcame a bacterial or some other systemic infection, and is a positive, not negative sign. Some women may have multiple parallel white bands or lines on the fingernails marking menstrual cycles when marginal zinc deficiency was present.
Anorexia
Zinc deficiency may cause a decrease in appetiteAppetite
The appetite is the desire to eat food, felt as hunger. Appetite exists in all higher life-forms, and serves to regulate adequate energy intake to maintain metabolic needs. It is regulated by a close interplay between the digestive tract, adipose tissue and the brain. Decreased desire to eat is...
which can degenerate into anorexia
Anorexia (symptom)
Anorexia is the decreased sensation of appetite...
or anorexia nervosa
Anorexia nervosa
Anorexia nervosa is an eating disorder characterized by refusal to maintain a healthy body weight and an obsessive fear of gaining weight. Although commonly called "anorexia", that term on its own denotes any symptomatic loss of appetite and is not strictly accurate...
. Appetite disorders, in turn, cause malnutrition
Malnutrition
Malnutrition is the condition that results from taking an unbalanced diet in which certain nutrients are lacking, in excess , or in the wrong proportions....
and, notably, inadequate zinc intake. Anorexia itself is a cause of zinc deficiency, thus leading to a vicious cycle: the worsening of anorexia worsens the zinc deficiency. The use of zinc in the treatment of anorexia has been advocated since 1979 by Bakan. At least 15 trials showed that zinc improved weight gain in anorexia. A 1994 randomized, double-blind, placebo-controlled trial showed that zinc (14 mg per day) doubled the rate of body mass increase in the treatment of anorexia nervosa (AN).
Deficiency of other nutrients such as tyrosine
Tyrosine
Tyrosine or 4-hydroxyphenylalanine, is one of the 22 amino acids that are used by cells to synthesize proteins. Its codons are UAC and UAU. It is a non-essential amino acid with a polar side group...
and tryptophan
Tryptophan
Tryptophan is one of the 20 standard amino acids, as well as an essential amino acid in the human diet. It is encoded in the standard genetic code as the codon UGG...
(precursors of the monoamine neurotransmitter
Neurotransmitter
Neurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to...
s norepinephrine
Norepinephrine
Norepinephrine is the US name for noradrenaline , a catecholamine with multiple roles including as a hormone and a neurotransmitter...
and serotonin
Serotonin
Serotonin or 5-hydroxytryptamine is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract, platelets, and in the central nervous system of animals including humans...
, respectively), as well as vitamin B1 (thiamine
Thiamine
Thiamine or thiamin or vitamin B1 , named as the "thio-vitamine" is a water-soluble vitamin of the B complex. First named aneurin for the detrimental neurological effects if not present in the diet, it was eventually assigned the generic descriptor name vitamin B1. Its phosphate derivatives are...
) could contribute to this phenomenon of malnutrition-induced malnutrition.
Cognitive and motor function impairment
Cognitive and motor function may also be impaired in zinc deficient children. Zinc deficiency can interfere with many organ systems especially when it occurs during a time of rapid growth and development when nutritional needs are high, such as during infancy. In animal studiesAnimal studies
Animal studies is a recently recognized field in which animals are studied in a variety of cross-disciplinary ways. Scholars from fields as diverse as: art history, anthropology, biology, film studies, geography, history, psychology, literary studies, museology, philosophy, and sociology; and from...
, rats who were deprived of zinc during early fetal development exhibited increased emotionality, poor memory, and abnormal response to stress which interfered with performance in learning situations. Zinc deprivation in monkeys showed that zinc deficient animals were emotionally less mature, and also had cognitive deficits indicated by their difficulty in retaining previously learned problems and in learning new problems. Human observational studies show weaker results. Low maternal zinc status has been associated with less attention during the neonatal period and worse motor functioning. In some studies, supplementation has been associated with motor development in very low birth weight
Birth weight
Birth weight is the body weight of a baby at its birth.There have been numerous studies that have attempted, with varying degrees of success, to show links between birth weight and later-life conditions, including diabetes, obesity, tobacco smoking and intelligence.-Determinants:There are...
infants and more vigorous and functional activity in infants and toddlers.
Diarrhea and pneumonia
Zinc deficiency contributes to an increased incidence and severity of diarrhea and pneumonia. Studies have shown that zinc treatment results in a 25 percent reduction in duration of acute diarrhea and a 40 percent reduction in treatment failure or death in persistent diarrhea. The studies determined that a ten-day therapy of zinc treatment can considerably reduce the duration and severity of diarrheal episodes, decrease stool output, and lessen the need for hospitalization. Zinc may also prevent future diarrhea episodes for up to three months. The current World Health OrganizationWorld Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
recommendation for diarrhea control includes the use of 20 mg per day of zinc supplementation for 10 to 14 days (10 mg per day for infants under the age of six months). A zinc taste test may have potential for diagnosing deficiency.
Pregnancy
Zinc deficiency during pregnancy can negatively affect both the mother and fetus. Animal studies indicate that maternal zinc deficiency can upset both the sequencing and efficiency of the birth process. An increased incidence of difficult and prolonged labor, hemorrhage, uterine dystociaDystocia
Dystocia is an abnormal or difficult childbirth or labour. Approximately one fifth of human labours have dystocia.Dystocia may arise due to incoordinate uterine activity, abnormal fetal lie or presentation, absolute or relative cephalopelvic disproportion, or a massive fetal tumor such as a...
and placental abruption has been documented in zinc deficient animals. These effects may be mediated by the defective functioning of estrogen via the estrogen receptor, which contains a zinc finger protein. A review of pregnancy outcomes in women with acrodermatitis enteropathica, reported that out of every seven pregnancies, there was one abortion and two malfunctions, suggesting the human fetus is also susceptible to the teratogenic effects of severe zinc deficiency. However, a review on zinc supplementation trials during pregnancy did not report a significant effect of zinc supplementation on neonatal survival.
Vitamins A and D
Plasma zinc levels have been found to be dependent upon vitamins A and D. This suggests that a Vitamin A or D deficiency could cause a secondary zinc deficiency and that for treatment of zinc deficiency one should ensure adequate vitamin A and D intake.Hunger
The influence of zinc on hunger is complex and likely depends upon the status of other nutrients, the developmental stage of the animal, and percentage body fat. Some research groups have argued for a role of zinc deficiency decreasing appetite, while others have shown zinc ingestion can reduce feelings of hunger by increasing leptinLeptin
Leptin is a 16 kDa protein hormone that plays a key role in regulating energy intake and energy expenditure, including appetite and metabolism. It is one of the most important adipose derived hormones...
levels. There is evidence that the way zinc influences hunger depends on the sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
/osmotic status of the organism, with low sodium/low zinc levels increasing hunger and high sodium/low zinc levels decreasing it. An organism with a low level of zinc has an increased susceptibility to hypoosmotic stress and cell rupture. Thus if the osmotic pressure is too low the organism may be inclined to eat to raise osmolality and prevent osmotic shock
Osmotic shock
Osmotic shock or osmotic stress is a sudden change in the solute concentration around a cell, causing a rapid change in the movement of water across its cell membrane. Under conditions of high concentrations of either salts, substrates or any solute in the supernatant, water is drawn out of the...
. It should be noted that zinc is known to affect osmolality by increasing sodium retention.
In rats, the "first visible sign" of zinc deficiency is a decreased appetite.
Treatment
Zinc supplementation has been shown to reduce diarrhea prevalence and mortality in children younger than 5 years of age.To combat zinc deficiency, five intervention strategies can be used:
- Supplementation using medicines
- Food fortification through the incorporation of zinc additives in food
- Dietary modification/diversification
- Genetic biofortification through plant breeding
- Agronomic biofortification through zinc fertilization.
These five intervention strategies may be used individually or in combination, depending on the setting, target group and degree of zinc deficiency.
The amount of zinc absorbed by the human body is a function of dietary intake of both zinc and phytate
Phytic acid
Phytic acid is the principal storage form of phosphorus in many plant tissues, especially bran and seeds. Phytate is not digestible to humans or nonruminant animals, however, so it is not a source of either inositol or phosphate if eaten directly...
(a phosphate storage compound that chelates
Chelation
Chelation is the formation or presence of two or more separate coordinate bonds between apolydentate ligand and a single central atom....
zinc), because the ratio between these two substances affects the bioavailability of zinc. Meeting the needs for absorbed zinc requires an increase in the zinc content and/or a decrease in the phytate content.
Plants, crops, and soils
Zinc is an essential micronutrient needed not only by people but also by crops. Almost half of the world’s cereal crops are deficient in zinc, leading to poor crop yields.Many agricultural countries around the world are affected by zinc deficiencies.
In China, zinc deficiency occurs on around half of the agricultural soils, affecting mainly rice and maize.
In India, zinc-deficient soils occupy almost 50% of the agricultural area and are a critical constraint on yield, but crops are highly responsive to zinc fertilization.
In Turkey, major yield and quality benefits in wheat have been obtained with the widespread use of zinc fertilizers, where half of the cereal growing land is zinc-deficient.
Research has shown that areas with zinc-deficient soils are often regions with widespread zinc deficiency in humans.
A basic knowledge of the dynamics of Zn in soils, understanding of the uptake and transport of Zn in plant systems and characterizing the response of plants to Zn deficiency are essential steps in achieving sustainable solutions to the problem of Zn deficiency in plants and humans (Zinc in soils and crop nutrition), International Fertilizer Industry Association (IFA)and International Zinc Association (IZA).)
Fertilization
Experiments show that soil and foliar application of zinc fertilizer can effectively reduce the phytate:zinc ratio in grain. People who eat bread prepared from zinc enriched wheat show a significant increase in serum zinc, suggesting that the zinc fertilizer strategy may be a viable commercial approach to address zinc deficiencies in humans.Where zinc deficiency is a limiting factor, zinc fertilization can increase crop yields. Balanced crop nutrition supplying all essential nutrients, including zinc, is a cost effective management strategy. Even with zinc-efficient varieties, zinc fertilizers are needed when the available zinc in the topsoil becomes depleted.
Plant breeding, including modern biotechnology, can improve:
Zinc uptake capacity of plants under soil conditions with low chemical availability of zinc;
Zinc translocation, thus elevating zinc content in edible crop parts rather than the rest of the plant;
Zinc bioavailability.
For optimal efficiency, zinc-efficient genotypes should be associated with complementary soil crop management (including fertilization) to ensure adequate zinc uptake by roots and thus enhance zinc nutrition of crops and humans
Turkey
Central Anatolia, in Turkey, was a region with zinc-deficient soils and widespread zinc deficiency in humans. In 1993, a research project found that yields could be increased by 6 to 8-fold and children nutrition dramatically increased through zinc fertilization.Through a partnership with Cukurova University, the State and the private company TOROS Agri Industry Group, zinc was added to fertilizers. While the product was initially made available at the same cost, the results were so convincing that Turkish farmers significantly increased the use of the zinc-fortified fertilizer (1 per cent of zinc) within a few short years, despite the repricing of the products to reflect the added value of the content.
Today, nearly 10 years after the identification of the zinc deficiency problem, the total amount of zinc-containing compound fertilizers produced and applied in Turkey reached a record level of 300,000 tonnes per annum. It is estimated that the economic benefits associated with the application of Zn-fertilizers on Zn deficient soils in Turkey is around US$ 100 million per year. Zinc deficiency in children has been dramatically reduced.
Such a policy could be easily replicated around the world in the many zinc-deficient countries.
External links
- International Zinc Association (IZA)
- HarvestZinc: HarvestPlus Zinc Fertilizer Project
- Proceedings from the Zinc Crops Conference on Improving Crop Production and Human Health, Istanbul, Turkey, 24–26 May 2007
- CIMMYT Solving the Zinc Problem from Field to Food
- Enriching Grain with Micronutrients: Benefits for Crop Plants and Human Health by Cakmak, I., Sabanci University, Turkey.
- Identification and correction of widespread zinc deficiency problem in Central Anatolia , Turkey by Cakmak, I., Sabanci University, Turkey
- Zinc in Soils and Crop Nutrition, International Zinc Association
- Fertilizers, Nutrition and Human Health