Lactoferrin and common colds

Respiratory tract infections (RTI's) are responsible for a significant number of morbidity and mortality worldwide. They are among the top 10 leading causes of death worldwide and are among the leading causes of death in children under 5 years of age.1
Therefore, supporting the immune system is an important issue especially in the current season at the peak of RTI`s.
In recent years, the positive effects of lactoferrin (Lf) on common infectious diseases such as the common cold or flu infection have been repeatedly reported. Lf could be a key factor in supporting the immune system and preventing colds.2
This is the conclusion of a recent meta-analysis of 25 studies on the reducing effect of lf intake on inflammatory mediators, immune cell activity and the occurrence and severity of RTI´s.
Especially in children and infants, it was clearly shown that Lf can reduce the incidence of RTI´s, which indicates improved immune function. Typical symptoms such as coughing, wheezing and rhinitis were successfully reduced, but also the overall incidence of respiratory infections and also the duration of illness was reduced.
Lf also appears to have the potential to have a positive effect on respiratory infections in adults.2
Another meta-analysis published last year also showed a therapeutic efficacy of Lf with regard to RTIs across all age groups. The research group Ali et al. showed a significant correlation between the intake of Lf and a reduced risk for the occurrence of RTIs.2 The duration of a respiratory disease as well as the severity of the symptoms could also be significantly reduced, which is also confirmed by the results of the current meta-analysis.{1,2}
RTIs are mainly caused by bacteria or viruses.
Therefore, the described effects of Lf on RTIs are mainly due to the anti-bacterial, antiviral and immunomodulatory properties of the protein.{2}

Antiviral

  • direct antiviral effect of Lf:
  • blocking viral receptors such as heparan sulphate proteoglycans by Lf binding to these receptors and blocking the "entrance" into the host cell {1-4}
  • the reduction of viral replication by inducing type I IFN production {1-3}
  • indirect antiviral effect by influencing immune cells (see below). {2}
  • In addition, significant antiviral potential against influenza A virus was confirmed in vitro. Lf was shown to suppress influenza A virus-induced apoptosis, haemagglutination, i.e. the clumping of erythrocytes, and subsequent infectivity. {1,5}
The antiviral activity of Lf was also discussed in more detail in our first news article: Mercurius Production (mercurius-production.com)

Immunomodulatory

As a natural component of the innate immune system, Lf can support both this and the adaptive immune system by activating important immune cells such as dendritic cells and leukocytes.
Especially in older people from the age of 40, it was shown that Lf can increase the activity of natural killer cells, i.e. innate immunity. Natural killer cells belong to the lymphocytes, which have a cytotoxic effect, i.e. they can destroy harmful cells. 2
The presence of Lf receptors on a range of immune cells confirms a multifaceted role of Lf in modulating the immune system, both innate and adaptive. 1-3

Antibacterial

  • Lf can breach the bacterial cell membrane by binding and sequestering the lipopolysaccharide (LPS) found in the cell membrane of Gram-negative bacteria Preventing the initiation of the LPS-mediated proinflammatory cascade and the resulting cell damage by inhibiting bacterial adhesion and entry into the host cell {1,2,6}
  • Inhibition of bacterial growth through the direct binding of iron (iron promotes bacterial growth) "Starvation" of pathogenic bacteria {1,2}
Overall, the administration of Lf to RTIs has already shown promising, sometimes significant efficacy in different age groups. {1,2}
The authors Ali et al. also conclude from the results of their metaanalysis that current evidence supports fortifying infant formula with Lf. {1}
In adults, the results also suggest that Lf can play a positive role in the treatment of symptoms and recovery of patients suffering from RTIs. {1,2}
However, this still requires further research for evidence.