Although whole grains and cereals are high in zinc, they also contain chelating phytates which bind zinc and reduce its bioavailability. Oral repletion via tablets (e.g. zinc gluconate) or liquid (e.g. zinc acetate). Oral zinc supplementation in healthy infants more than six months old has been shown to reduce the duration of any subsequent diarrheal episodes by about 11 hours. Oral repletion via multivitamin/mineral supplements containing zinc gluconate, sulfate, or acetate. It is not clear whether one form is better than another. Epidemiology
Zinc deficiency affects about 2.2 billion people around the world. Severe zinc deficiency is rare, and is mainly seen in persons with acrodermatitis enteropathica, a severe defect in zinc absorption due to a congenital deficiency in the zinc carrier protein ZIP4 in the enterocyte. Mild zinc deficiency due to reduced dietary intake is common. Conservative estimates suggest that 25% of the worlds population is at risk of zinc deficiency. Zinc deficiency is thought to be a leading cause of infant mortality.Providing micronutrients, including zinc, to humans is one of the four solutions to major global problems identified in the Copenhagen Consensus from an international panel of economists. History
Significant historical events related to zinc deficiency began in 1869 when zinc was first discovered to be essential to the growth of an organism Aspergillus niger. In 1929 Lutz measured zinc in numerous human tissues using the dithizone technique and estimated total body zinc in a 70 kg man to be 2.2 grams. Zinc was found to be essential to the growth of rats in 1933.
By 2014 over 300 zinc containing enzymes have been identified, as well as over 1000 zinc containing transcription factors.Phytate was recognized as removing zinc from nutrients given to chicken and swine in 1960. That it can cause human zinc deficiency however was not recognized until Reinholds work in Iran in the 1970s. This phenomenon is central to the high risk of zinc deficiency worldwide. Soils and crops
Soil zinc is an essential micronutrient for crops. Almost half of the worlds cereal crops are deficient in zinc, leading to poor crop yields. Many agricultural countries around the world are affected by zinc deficiency. In China, zinc deficiency occurs on around half of the agricultural soils, affecting mainly rice and maize. Areas with zinc deficient soils are often regions with widespread zinc deficiency in humans. A basic knowledge of the dynamics of zinc in soils, understanding of the uptake and transport of zinc in crops and characterizing the response of crops to zinc deficiency are essential steps in achieving sustainable solutions to the problem of zinc deficiency in crops and humans. Biofortification
Soil and foliar application of zinc fertilizer can effectively increase grain zinc and reduce the phytate:zinc ratio in grain. People who eat bread prepared from zinc enriched wheat have a significant increase in serum zinc.Zinc fertilization not only increases zinc content in zinc deficient crops, it also increases crop yields. Balanced crop nutrition supplying all essential nutrients, including zinc, is a cost effective management strategy.