Zinc deficiency causes dwarfism. Symptoms include anaemia, impaired development of the genitals and retarded growth.
It also causes infertility, low sperm production, reduced testosterone level, irregular menstrual cycle, sexual impotence and slow sexual maturation.
Besides that, it impairs taste, smell senses and loss of appetite. Long term loss of zinc causes lethargy, mental disturbances and sleep disorders.
It also causes slow wound healing and skin problems such as acne, eczema and psoriasis. Lack of zinc causes increased susceptibility to infections. Low level of zinc increases the level of dihydrotestosterone that causes enlarged prostate or benign prostatic hyperplasia (BPH).
Who is at risk?
Studies showed that delayed healing of wounds and poor growth performance are signs of possible zinc deficiency. Children entering their principal growth periods, pregnant or lactating women and women with heavy menstrual losses experience zinc shortages.
Formula-fed babies also require more zinc because cow’s milk has low content of zinc. In addition, people who are recovering from gastrointestinal surgery have difficulty in absorbing zinc.
The importance of zinc for our body
It is needed in nucleic acid synthesis. It is a component of DNA and RNA polymerase. Nucleic acid is important in protein synthesis and biological functions. It is important in cell growth and development.
It is also a part of several enzymes that are involved in digestion and metabolism. It is needed in carbon dioxide metabolism and respiration processes. It plays a role in protein, carbohydrates and lipid metabolism. It is also important in insulin actions that regulate blood glucose level.
It is also essential in the immune system. It is needed by neutrophiles and T-lymphocytes to protect the body.
It is also need by thymic hormone to stimulate immune actions. It is important in sexual reproduction system, sperm production and testosterone synthesis. It affects sexual maturation, fertility and menstrual cycle too.
Zinc, with vitamin A, is needed to maintain healthy vision and adjustment in the dark environment. It also maintains vitamin A level in the blood.
It is also and antioxidant that neutralises toxic metal such as cadmium and mercury. Zinc is essential in taste and smell senses.
The daily requirement of zinc
The daily requirement for an adult is 15 mg.
Source of zinc
Zinc can be found in oysters, shellfish, red meat, beef, cheese, egg, fish, nuts, seeds, whole grains and legumes.
Zinc is lost during processing food such as white rice. Milling causes 80% of the zinc to be lost. However, very little zinc is lost in home preparation because like all minerals (unlike most vitamins) zinc is not heat-sensitive.
Acute zinc poisoning causes gastrointestinal pain, nausea, vomiting, dizziness, metallic taste and diarrhea.
High level of zinc also causes impaired immune system and may reduce HDL.
Zinc sulphate is given to anorexia nervosa patients to help them gain weight.
Zinc supplement is also given to AIDS (acquired immunodeficiency syndrome) patients to help them reduce the risk of infection.
Zinc increases the number of T-lymphocytes that assist in fighting infection. Zinc is also given to rheumatoid arthritis patients (as an antioxidant).
Zinc supplement is used to treat dwarfism that occurred as a result of zinc deficiency. Zinc supplement is given to children with retarded growth and sexual development.
Ointment that contains zinc is used to treat some skin diseases such as acne, dermatitis and psoriasis. It increases the rate of wound healing process but not in the condition when zinc level is normal.
Zinc supplement is also used to treat common cold but evidences are conflicting.