Zinc deficiency increases the risk of virus infections and subsequent dangerous pneumonia

Zinc has many different functions in the immune defense and a zinc deficiency increases the risk of infections and diarrhea, which are global causes of disease and mortality. According to a study published in Physiological Reports, being zinc-deficient can also lead to influenza complications such as bacterial pneumonia that is potentially lethal. The authors assume that zinc plays a key role in the body’s defense against respiratory infections, including COVID-19. They write that factors such as unhealthy diets, ageing, alcoholism, intestinal diseases, and various types of medicine can increase the body’s need for zinc.

Nearly 50 percent of infant deaths worldwide are caused by infectious diseases, with pneumonia and diarrhea being the primary problems. Pneumonia is also a frequent reason for hospitalization of older people and weak or chronically ill patients, and the disease is associated with high mortality.
An estimated 20 percent of the world’s population is zinc-deficient, and the problem is particularly widespread in the underdeveloped countries and contributes to the increasing infant mortality.
In some countries, zinc supplements are used to treat diarrhea among children under the age of five years as part of the normal treatment for dehydration.
In Western countries, zinc deficiency is related to ageing processes, unhealthy diets, and alcohol abuse. Overconsumption of calcium and iron, diarrhea, celiac disease, and the use of diuretics can also impair the body’s uptake or excretion of zinc.
Several studies suggest that zinc deficiency increases the risk of respiratory infections. Still, epidemiological data (including randomized, controlled studies) of zinc supplementation in connection with lower respiratory tract infections show conflicting results. This is what the scientists wanted to take a closer look at in the current study.

Zinc deficiency plays a crucial role in the pathogenesis of respiratory infections

The study was carried out on mice that were given a diet which made them 50 percent zinc-deficient. Afterwards, the mice were introduced to influenza A (H1N1) and methicillin-resistant yellow staphylococcus (MRSA). This specific combination is relevant because virus infections such as influenza can burden the immune defense in old and weak people and cause bacteria from the natural bacterial flora in the upper respiratory tract to spread to the lungs, which can result in serious infection. Also, one becomes more susceptible to infections from things like MRSA. The study showed that the mice contracted the two infections. Also, the scientists observed that the combination of these infections and zinc deficiency caused more serious damage to the lung tissue. This was revealed through elevated levels of markers (BAL protein) of damage to the pulmonary epithelium. The mice also demonstrated reduced activity of the genes that are related to the health and integrity of the pulmonary epithelium.
The epithelium covers surfaces on mucous membranes, organs, and blood vessels. In connection with virus infections, the epithelium releases various cytokines to attract white blood cells that fight virus. Virus infections can also cause apoptosis (programmed cell death) in the pulmonary alveolus, where a constant exchange between oxygen and CO2 takes place. If these reactions become too powerful due to unwanted gene activity, it may result in a cytokine storm, hyperinflammation, and pulmonary regurgitation, and other derailed reactions that can be life-threatening.
Bacterial pneumonia accounts for 25-50 percent of the complications and deaths that occur in the wake of virus infections with influenza A, and the scientists therefore conclude that zinc deficiency plays a key role in the pathogenesis of respiratory infections and bacterial pneumonia.

Zinc deficiency also increases the risk of other infections

The study authors also mention other studies that show that zinc deficiency can increase the risk of infections with pneumococcus (streptococcus pneumonia) and blood poisoning. Rats with alcohol-induced zinc deficiency were less able to fight an infection with Klebsiella pneumonia, but the study authors were more interested in studying zinc’s role in connection with influenza with reference to various pandemics in the past century that have results in millions of deaths.
The body’s zinc status is also important for the body’s defense against other RNA viruses such as COVID-19, so it is important to always have enough zinc.

Zinc’s role in the immune defense and for protecting cells

Zinc is important for the innate immune defense that fights nearly all germs and for the adaptive immune defense, where T cells are responsible for the primary protection and immunity against virus infections.
Zinc’s close interaction with vitamin D is also important for the immune defense and for regulating inflammation. Zinc is also part of the powerful SOD antioxidant that protects cells against damage caused by free radicals, including the free radicals that are generated by infections and should be controlled to prevent them from starting dangerous chain reactions. Moreover, zinc is involved in different proteins that are responsible for activating the right genes at the right time.

According to the NHANES III study (National Health and Nutrition Examination Survey), 35-45 percent of people aged 60 years and older don’t get enough zinc from their diet.

Zinc sources, requirements, and supplementation

Zinc is primarily found in animal food sources and whole grain, kernels, and beans. Plant foods contain phytin, which reduces the body’s zinc absorption. It is easier for the body to absorb zinc from animal food sources.
The recommended dietary intake of zinc (in Denmark) is 10 mg. Infections increase the body’s need for zinc to help support the immune system and all other zinc-dependent functions. According to EFSA (the European Food Safety Authority), the safe upper intake level for zinc is 25 mg per day, but it is safe and harmless to take an even larger dose for a short period of time.
A Finnish meta-analysis of cold-ridden people showed that those who took high doses of zinc (80-92 mg daily) recovered several days earlier than those who did not take supplements. Always choose a quality that the body can easily absorb and utilize. It is not recommended to take large therapeutic doses of zinc for longer periods, as this can result in iron and copper deficiency.

References:

Radha Gopal et al. Zinc deficiency enhances sensitivity to Influenza A associated bacterial pneumonia in mice. Physiological Reports 2024

Ashton Amos, Mahammed S. Razzaque. Zinc and its role in vitamin D function. Current Research in Physiology. 2022

University of Helsinki. Zink acetate lozenges may increase the recovery rate from the common cold by three-fold. ScienceDaily 2017