The role of zinc in antiviral</br>defence

The role of zinc in antiviral
defence

After iron, zinc is the most abundant trace element in the body (2 to 4 g). 98 % is found in our cells and just 1 % in the plasma.

Zinc, a trace element essential to many physiological roles

Zinc is involved in the activity of more than 300 metalloproteins and metalloenzymes where it acts as a metallic cofactor. This means that these specific proteins and enzymes can only function if zinc plays a structural or regulatory role.

Zinc is essential then to multiple biological reactions (immunity, growth, insulin synthesis, etc.) and plays a major role in the body in all major metabolic processes and physiological mechanisms.

Zinc and immunity

A cause and effect relationship has been recognised and accepted by EFSA1 between dietary intake of zinc and normal immune system function. In fact, zinc plays a dominant role in the body’s natural defences, from maintaining the skin barrier to immune cell activity.

Zinc is involved in the function of thymulin, a hormone which stimulates the development and maturation of T lymphocytes in the thymus. These cells play a major role in the immune response, as they recognise and fight against foreign bodies, pathogens and cells infected with the virus.

In addition, scientific studies have shown numerous mechanisms by which zinc is involved in the viral replication cycle2. Replication is the phenomenon by which the virus, once it has infected a cell, multiplies and produces new viruses, thus spreading the infection to other cells.

The role of zinc in the antiviral response can be summarised in 2 actions therefore:

  • Improvement of the immune response (activation of T lymphocytes)
  • Inhibition of viral replication and of multiplication of the virus in the body

THE ANTIVIRAL POTENTIAL OF ZINC IS THE FOCUS OF NUMEROUS STUDIES

A high number of studies have addressed the effect of zinc supplementation on various viral infections. In fact, there would be benefits for the immune response from supplementation in the face of a wide variety of viruses, the best known effects being those observed in the rhinovirus which is responsible for colds and respiratory disease2.

One study3 in vitro observed that an increase in intracellular zinc concentration effectively impairs replication of RNA viruses such as the influenza virus, poliovirus and certain coronaviruses.

Zinc requirements and risk of deficiency

In the general population, the recommended dietary allowance for zinc varies between 8 mg for women and 11 mg for men. It is also about 11 mg daily for pregnant women. It is still advisable not to exceed a dose of 15 mg zinc per day, from all sources (7 mg for children aged from 10 to 18 years, 3 mg for children aged less than 10 years).

Although serious cases are rare, mild to moderate deficiencies are common and may affect up to one third of the world’s population4. Our bodies have no significant reserves of zinc so it is important to ensure a regular supply through the diet.

In major zinc deficiencies, one of the most commonly observed signs is the loss of smell and taste5 because zinc is involved in the synthesis of gustin, a protein vital to the perception of taste in the taste buds.

Skin problems, wound healing difficulties, hair loss, reproductive disorders and increased sensitivity to infection have also been observed.

POPULATIONS SENSITIVE TO ZINC DEFICIENCY

Some people are particularly vulnerable to the risk of zinc deficiency:

  • Older people: It has been demonstrated that 50 % of older people living in institutions have zinc deficiency6.
  • People with diabetes: Zinc deficiency is more common in people with type 2 diabetes7.

Pregnant women: Because of increased requirements, pregnant women also represent a population potentially more susceptible to zinc deficiency.

Zinc and food

Zinc is found in many foods such as fish or red meat. Vegan diets are very often deficient in zinc, however.

To ensure efficient absorption, it is important to avoid combining it with too many cereals or legumes rich in phytates and to avoid consuming too many preserves because preservatives are mineral traps.

Phytates are actually compounds found in vegetables (maize, rice, cereals, legumes) which bind to certain metals including zinc and prevent their efficient intestinal absorption.

THE WORDS OF CLAUDE LAGARDE, DOCTOR OF PHARMACY, MEDICAL BIOLOGIST AND FOUNDER OF NUTERGIA

“After more than 25 years of working with patients and observing the benefits of zinc, I am now convinced that it plays a major protective role and that it boosts our antiviral immune defences by its dual action both on our innate immunity and on adaptive immunity.

Although it is found in many foods, zinc is not always efficiently absorbed depending on the individual’s diet. In addition, it is important to understand that stress reduces its activity and promotes its elimination. That is why you may need supplements.

I advise 10 mg per day every day because it cannot be stored. And 10 mg is equivalent to 100 % of the recommended dietary allowance (RDA).”