Zinc is an essential trace element, essential for the proper functioning of the body.
Zinc from the diet is absorbed in the intestine thin thanks to a low molecular weight protein called metallothionein (protein rich in cysteine). Absorption depends on the amount of zinc in the diet and may be decreased by the presence of fibers and phytates present in cereals , calcium, copper, cadmium and other trace elements that can replace zinc in the transport protein.
Most zinc is intracellular. 90% is distributed between bone and muscle tissue, and the rest is distributed in the skin, liver, pancreas, retina, blood cells and cells of the gonads in men. The rate of exchange of this trace element is greater in red blood cells, gonads, muscle and skin, than in bones or teeth.
It is excreted in the feces through pancreatic and intestinal secretions, and to a lesser extent through urine. High alcohol consumption, liver problems, and metabolic stress states increase renal zinc loss. The regeneration of the skin and hair consume a large amount of zinc.
The main dietary sources of this trace element are marine products, mainly shellfish . Also red meat, eggs , pumpkin seeds and whole grains are also a source of zinc (the latter are not very interesting due to its high content of phytates).
Cooking and processing of food are one of the main causes of zinc loss, especially in cereals that can lose up to 80% of their content in this mineral after cooking.
The daily amounts of zinc vary greatly depending on the endogenous losses of this. In addition, special situations such as pregnancy, lactation, athletes, etc. may have higher zinc needs.
In our society it is relatively common to have zinc deficiency. Deficiency states can be caused by different reasons: intestinal problems, high stress needs, different pathologies, etc. The most common manifestations of zinc deficiency are:
- Dermatitis or other skin problems.
- Alopecia or hair loss.
- Brittle nails with white spots.
- Altered sense of taste and sight.
- Problems in wound healing.
- Alterations in sexual maturity and reproductive capacity. Prostate problems.
- Anorexia and weight loss.
- Depression of the immune system. Reduced activation of T lymphocytes and apoptosis of B lymphocytes.
- Diabetes or problems in the manufacture of insulin.
- Metabolic acidity.
- Delayed body growth in children.
Lower concentrations in plasma of 50 mg / 100 ml and in hair of 70 mg are indicative of deficiency . It is also possible to study the blood levels of carbonic anhydrase in red blood cells, or the levels of alkaline phosphatase in serum and / or saliva.
Functions of zinc
Zinc has a series of properties that make it essential for the body. It acts as a catalyst for many enzymatic reactions. It is not useful for oxidation-reduction reactions because it does not oxidize and can be transported and used safely. Zinc plays a fundamental role for the integrity of histones (proteins linked to DNA) and polymerases (enzymes responsible for the synthesis of DNA protein) , so it is vital for the growth and repair of tissues.
- Its main functions are:
- Manufacture of hormones, mainly insulin and testosterone.
- Development and maturation of the reproductive organs . It is useful to improve fertility and reproduction.
- Helps wound healing , repair of hair, skin and nails .
- Regulates the acid-base balance of body fluids.
- Essential for the proper functioning of the brain . It can be useful for the treatment of neurodegenerative pathologies (Parkinson’s, Alzheimer’s…).
- It improves immune function . It is especially useful for the treatment of recurrent herpes zoster.
- Better cardiorespiratory function and promotes muscular strength . It can be useful for athletes or people with hypertension.
- Caring for bones and teeth .
- Helps to respond to physical stress and emotional .
- Cytoprotective: antioxidant properties of mitochondria , etc.
- Improves ocular function and the sense of taste . It is important for night vision.
- Participates in the production of pancreatic enzymes and intestinal juices .
Zinc is the least toxic trace element, although supplementation with 2,000 mg. a day of zinc gluconate in healthy 17-year-olds for more than 12 months caused intoxication (anemia, leukopenia and neutropenia). Toxic effects were reduced when supplementation stopped. In any case, supplementation with zinc has been shown to be the most effective way to meet daily needs in people with deficits or high needs.