Zinc mineral is the component of more than 300 enzymes. It is present in small amount in all tissues but the highest concentration is found in bones, prostate gland, and the eyes. It is a versatile trace element in our body. Zinc plasma level is about 96µg per 100 ml for healthy adults and 98 µg per 100 ml for healthy children. The average adult body is composed of about 1.4-2.3 gram of zinc.
It is widely distributed in food-stuffs both of animal as well plant origin.
- Animal Foods: These contain zinc in the milk, meat, yogurt, fish, chicken, oysters, crab lean and poultry.
- Plant Foods: Zinc is present in the vegetables as well as in the fruits. These include spinach, broccoli, tomato, green beans, green peas, whole wheat, lentils apple, banana, and oranges etc.
- Zinc takes part in a large number of enzymes reaction such as those catalyzed by transferases, hydrolases, lyases, isomerases, ligases, oxidoreductases, transcription factors and specific enzymes include; RNA polymerase, glucocorticoids receptors, uricases, carbonic anhydrase, lactate dehydrogenase, alkaline phosphatase, and alcohol dehydrogenase.
- Zinc is also involved in nuclei acid dehydrogenation.
- It assists in immune functions and in growth and development. Since it is present in white blood cells.
- Zinc is important for the normal functioning of the reproductive, dermatologic, neurologic and gastrointestinal system.
- It is essential for normal sperm production, normal embryonic development, and for normal cell division and differentiation.
- It helps protect the body from heavy metal poisoning for example poisoning by the lead.
- It interacts with platelets in blood clotting, affects thyroid functions and influence behavior and learning performances.
- Zinc is necessary to produce the active form of vitamin A in visual pigments and the retinol-binding protein that transports vitamin A.
- Zinc is important for normal taste perception as well as in wound healing.
Deficiency and Symptoms
Human zinc deficiency was first reported in the 1960’s in Turkey, Egypt, and Iran in the young children. Middle Eastern diets are low in zinc-containing food such as meat, legumes etc so they mostly suffer from its deficiency.
The severe growth retardation and arrested sexual maturation characterize zinc deficiency. In addition, it hinders digestion and absorption, causing diarrhea which worsens malnutrition not only for zinc but for all nutrients. It impairs the immunity of a person, causing him to be more prone toward the infections. Chronic deficiency of zinc damages the nervous system as well as brain functioning. It also disturbs thyroid functions and metabolic rate. It alters taste sensations, causes anorexia and slow wound healing. In fact, its symptoms are so all-pervasive that generalized malnutrition and sickness are more likely to be the diagnosis than simple zinc deficiency.
The deficiency of zinc is common among pregnant women, young children, the elderly and the poor. Even a mild deficiency of zinc can result in poor growth, poor appetite and abnormal vision in darkness.
Accidental high does of zinc may cause vomiting, diarrhea, exhaustion, excessive salivation, fever, cough, and leukocytosis. Zinc toxicity may develop in welders and in those receiving excessive intravenous intake.