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- 04/01/2021

Respiratory Tract Infections and Antibiotic Resistance: A Protective Role for Vitamin D?

AgroFOOD Industry Hi Tech

Upper and lower respiratory tract infections are among the most common infections globally, and in the United Kingdom, they account for about half of all oral antibiotics prescribed. Antibiotic overuse and the emergence of “superbugs” that are resistant to their effects is a global problem that is becoming a serious concern. Considering this, the potential role of immunonutrition as a “prehabilitation” in helping to tackle bacterial infections and reduce over-reliance on antibiotic usage is gaining interest. This narrative mini-review summarizes current knowledge on the roles of certain nutrients in helping to modulate immune function, with particular focus on vitamin D. Vitamin D supplementation appears to reduce the risk of acute respiratory tract infections and thus could have a valuable role to play in reducing over-reliance on antibiotics. Investment in high-quality trials is needed to further explore this field.

There has been an upsurge of novel bacterial, viral, and fungal respiratory pathogens that are becoming increasingly challenging to treat, with respiratory tract infections (RTIs) being exacerbated by antibiotic resistance of Gram-positive and Grain-negative bacteria (1). Acute respiratory tract infections (ARTIs), which include upper respiratory tract infections (URTIs), are, among adults, the most common cause of antibiotic prescription (2). In the United Kingdom, an examination of over eight million patient records from 587 general practices showed that URTIs accounted for around 31% of oral antibiotic prescriptions and lower respiratory tract infections (LRTIs) accounted for around 19% (3).

The very first antibiotic, salvarsan, was developed in 1910 while penicillin discovery by Alexander Fleming followed in 1928 (4). Multiple antibiotics have been discovered since then, but now, after about 100 years of the “antibiotic era,” fewer new antibiotics are being identified and significant antibiotic resistance has emerged (4). The World Health Organization considers that the unprecedented use of antibiotics and subsequent antimicrobial resistance (AMR) is currently one of the largest threats to global health, food security, and human development (5, 6).

In 2016, ARTIs were responsible for ~2.38 million deaths globally (7, 8). Within the European Union, 25,000 people have been estimated to die annually because of AMR with resultant societal costs of around 1.5 billion euros annually (9). By 2050, it has been estimated that some 10 million people globally could die annually as a result of AMR—with 390,000 Europeans estimated to be affected and even larger proportions of Asian (4,730,000) and African (4,140,000) populations (6). It has been further predicted that standard antibiotic treatments may no longer work, subsequently making infections more difficult to treat and control (10).

Given the high prevalence of ARTIs coupled with rising rates of AMR, novel approaches are needed for the future. The concept of “prehabilitation,” including the role of immunonutrition, could play a pivotal role in helping to both prevent and offset RTIs should these occur. Prehabilitation has been well defined elsewhere as: “interventions that can help to improve patient’s health in advance of being exposed to a physiological stressor so they are then better able to cope with that stress” (11). This narrative mini-review describes how immunonutrition could become a valuable tool in conventional medicine. It focuses on ARTIs and vitamin D, for which there is an expanding body of evidence.