Is Human Saliva Equipped with Antibacterial Properties?

Have you ever wondered why our saliva doesn't have antibacterial properties to protect us from infections, like some other creatures? In fact, humans do have some inherent antibacterial properties in their saliva, such as histatin and nitrites, which can help with wound healing. But why don’t we have completely antibacterial saliva? Let's delve into the reasons behind this.

Why Humans Do Not Have Completely Antibacterial Saliva

There are a few key reasons why humans have not evolved to have entirely antibacterial saliva. First, bacteria evolve much faster than humans, so they could very likely develop resistance to anything our salivary glands produce. Second, the human body actually benefits from the natural growth of bacteria on and within it. We have a normal bacterial flora in our mouths, which may provide us with useful benefits, although we still have much to learn about these interactions.

Evolution and the Role of Bacteria

Throughout most of human history, we assumed that most bacteria were harmful. However, it is only recently that we have begun to understand the importance of our personal bacterial communities, or microbiome, in maintaining health. The human oral microbiome, similar to the gut microbiome, is essential for human well-being. Research has shown that there are over 600 species of bacteria in the human mouth, including Actinobacteria, Bacteroidetes, and many others.

These bacteria play a crucial role in maintaining a healthy oral environment. In fact, the absence of this community could lead to various oral health issues. Therefore, humans did not evolve fully antibacterial saliva because it would disrupt the delicate balance of the oral microbiome, which is essential for maintaining health.

Current Research on Human Oral Microbiome

The Human Oral Microbiome Database (HOMD) provides detailed insights into the oral microbiome. A paper from the HOMD database lists 619 taxa at the species level, distributed across 13 phyla. The study also analyzed 36,043 16S rRNA gene sequences from oral microbiota samples, identifying 1,179 taxa, many of which remain uncultivated. This research highlights the complex and diverse nature of the oral microbiome.

Conclusion: The Importance of Oral Bacteria

While fluoride toothpaste helps prevent dental issues, it may not be beneficial to have completely antibacterial saliva. The oral microbiome needs to stay in balance to maintain health. Therefore, it is advisable to maintain a balanced approach to oral care, rather than relying solely on antibacterial products.

References

The Human Oral Microbiome. Database including 619 taxa in 13 phyla: Actinobacteria, Bacteroidetes, Chlamydiae, Chloroflexi, Euryarchaeota, Firmicutes, Fusobacteria, Proteobacteria, Spirochaetes, SR1, Synergistetes, Tenericutes, and TM7. Analysis of 36,043 16S rRNA gene sequences to determine the relative abundance of taxa and identify novel candidate taxa.