The link between childhood asthma, hay fever, and zinc deficiency

Zinc deficiency is widespread, and a refined or plant-based diet increases the risk. The widespread zinc deficiency appears to contribute to the growing number of children who develop asthma and hay fever. In addition, zinc deficiency may be an overlooked factor that reduces the effectiveness of medical treatment, as shown in a review article published in Nutrients. According to the researchers, zinc plays a crucial role in maintaining strong mucous membranes, supporting immune function, and regulating inflammation. For this reason, zinc supplementation may represent a new, safe, and inexpensive complementary approach in the management of asthma and hay fever.

Asthma often begins in childhood, and the condition now affects around 7 percent of children aged 6-11 years, with prevalence continuing to rise. There is also an increasing incidence of allergic hay fever. Possible explanations for the sharp rise in asthma and other allergic conditions include population growth in urban areas, exposure to environmental pollutants, excessive hygiene, hypersensitivity, and unhealthy Western dietary patterns that lack essential nutrients.
Asthma and hay fever are characterized by weakened mucous membranes that allow allergens to pass through to the underlying tissue, along with an inappropriate immune response involving excessive histamine release and inflammation. Oxidative stress, with an excess of free radicals, is also present.
Conventional medical treatments include inhaled anti-inflammatory corticosteroids, antihistamines, and avoidance of allergens. However, these approaches are primarily aimed at symptom control and may also be associated with a range of side effects. As a result, there has been growing interest in alternative strategies and in nutrients that help regulate the immune system’s inflammatory response and maintain strong airway mucous membranes.
So far, attention has focused on vitamins A, C, D, and E, as well as iron, selenium, and zinc, since deficiencies in all of these nutrients are common among children and adolescents with asthma, hay fever, and other allergic conditions. In the new review article, the researchers took a closer look at the role of zinc by examining a range of studies published between 2015 and 2025, identified through databases such as PubMed and the Cochrane Library.

How is zinc deficiency linked to asthma and hay fever?

Zinc is a trace element involved in more than 300 enzymatic processes and is essential for the activation of numerous genes, stabilization of protein structures, and wound healing. Zinc also functions as an important antioxidant through superoxide dismutase (SOD), protecting cells and tissues from damage caused by free radicals and oxidative stress.
As a result, zinc plays a role in a wide range of metabolic processes and, in relation to immune function, helps support:

Maintenance of strong epithelial cells, including those lining the mucous membranes of the airways
Development of cells in the innate immune system, including various proteins, macrophages, and other white blood cells
Development of cells in the adaptive immune system, including T cells, B cells, and antibodies
Proper function of the thymus, where T cells are trained to distinguish between harmful and harmless targets (zinc deficiency causes the thymus to shrink, impairing T-cell development)
Regulation of the balance between Th1 and Th2 cells (in asthma and hay fever, there is an exaggerated Th2 response along with inappropriate production of histamine and IgE antibodies against harmless allergens)
Prevention of inappropriate inflammation
Support of cellular vitamin D receptors, which are essential for vitamin D’s immune-related functions
Antioxidant activity (SOD) that protects cell membranes, thereby reducing the formation of pro-inflammatory cytokines in the airways
Support of tissue repair following allergic reactions

In the review article, the authors describe how zinc deficiency leads to weakened mucous membranes, allowing allergens to penetrate more easily and trigger the immune system’s production of IgE antibodies and histamine in the underlying tissue.
The authors also explain how zinc deficiency can disrupt multiple components of the immune system, leading to cascades of unwanted reactions that trigger asthma or hay fever attacks.
Because zinc plays such a central role in mucosal integrity, immune function, and the prevention of asthma, hay fever, and other allergic diseases, the researchers suggest that zinc supplementation may be a relevant, safe, and supportive treatment option for these conditions.
For general prevention, it may also be beneficial to aim for a higher zinc intake through a healthy, balanced diet.

Zinc sources and reasons for widespread deficiency

A daily intake of zinc is required, as the body does not have an actual zinc storage system.
Good dietary sources of zinc include meat, liver, eggs, shellfish, fish, nuts, seeds, whole grains, and legumes. However, zinc is most easily absorbed from animal sources, and a strictly plant-based diet increases the risk of deficiency. Diets high in ultra-processed foods, excessive sugar, and unhealthy fats are also typically low in zinc. In addition, zinc absorption may be impaired by certain gastrointestinal disorders and by vitamin B6 deficiency.

In 2019, asthma affected an estimated 262 million people worldwide, and 455,000 deaths were attributed to the disease
Asthma is one of the leading causes of reduced quality of life and work disability
It is now estimated that 30 percent of younger Europeans suffer from asthma, hay fever, or other allergic conditions
Allergies are often closely linked to diet and lifestyle
Deficiencies of vitamins A, C, D, and E, as well as iron, selenium, and zinc, are common among children and adolescents with allergic diseases and hypersensitivity
References:

Giulio Dinardo et al. The Role of Zinc in Pediatric Asthma and Allergic Rhinitis. 2025

Liji Thomas. Why zinc may be the missing nutrient in childhood asthma care. News Medical Life Sciences. 2025

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