The human superorganism

Only a small part of our body is actually human! Most other cells are bacteria, but there are also eukaryotes, archaea and viruses. It is becoming increasingly clear that we are not only a host for these organisms, but that our microbiome, as it is collectively known, is separate part of every human being.  A highly complex system – responsible for efficiently providing substances which are necessary for our lives.
The Human Superorganism is complete only together with the microbiome, helping ensure its existence long term. Most diseases civilisation – be they diabetes, obesity, allergies, colon cancer, kidney stones, Irritable Bowel Syndrome, but also depression – are now associated with an imbalanced microbiota, or dysbiosis. 
Lactoferrin, in evolutionary terms, is a very old part of human innate immune system. It is probably due to the co-evolution of the microbiome and the immune system, that Lactoferrin can distinguish between harmful and beneficial bacterial species [1]. Lactoferrin does not attack the „good“ microorganisms, it actually promotes their probiotic activity, and in this way leads to a better, improved diversity within the microbiome [2]. 
The microbiome covers a wide range of bacteria, from harmless ones to potentially pathogenic germs. Sometimes, there’s only a thin dividing line between the two kinds. Ultimately, the interaction with the host, the human being, is the deciding factor.  Under various circumstances, a respective host and its immune status can be different.
The immune system’s purpose may be to eliminate potential pathogens, but it must also ensure that the balance is maintained, so that the host & microbes can co-exist as a Superorganism [3].  
In their article, Eberl et al. describe humans as a Superorganism.  They also discuss the direct functional, protective and immunological advantages that are brought about by the connection between the host and the microbiome.
Take the gut, for example: the microbes benefit from an environment that is regularly flooded with nutrients.  At the same time, the host benefits from the microbial activity, which complements digestive processes, degrades toxins, regenerates the epithelium and forms a barrier against potential pathogens. 
These microbial communities live on other body surfaces too, including the entire length of the digestive tract, the mucous membranes and the skin’s surface. 
In particular, the intestinal flora has an essential role within the immune system. The immune system is the result of many action-reaction processes, equating to a co-evolution between the individual components of the immune system and the microbes. This would explain how it can adapt reactively and maintain equilibrium within the functional Superorganism.
Homeostasis (equilibrium) within the Superorganism can be defined as the optimal coexistence of host and microbiome. This is a dynamic equilibrium in which the growth and movement of the microbes is constantly controlled by the host’s immune system.
A disturbance of the homeostasis, especially if it’s of a long-term nature, can lead to disease. An optimal therapy approach should address the primary cause, and also the immunological dysfunction [3].
Studies have shown that the microbiome has significant positive effects on both systemic and local immune responses, such as at the mucous membranes (including lungs) [4]. The administration of probiotics has been shown to be particularly helpful in the prevention of viruses in the airways [5]. 
In general, the function and number of immune cells improve by taking probiotics [6], which leads to an improved and more efficient immune defence. In addition, inflammatory mechanisms are inhibited and this modulation of the immune system helps prevent an excessive inflammatory reaction [7-9]. 
Supplementation with Lactoferrin alone contributes significantly to improving the composition of the intestinal flora.  The effect of the probiotics can also be increased in this way.  Harmful germs show a higher sensitivity to the anti-microbial effect of Lactoferrin, whereas probiotic bacteria much less so [10].
Several studies have shown that Lactoferrin increases the growth rate of beneficial bacteria such as Bifidobacterium bifidum, B. longum, B. lactis, B. infantis, Lactobacillus reuteri, L. rhamnosus and L. coryniformis [10-13] in contrast to its anti-bacterial action against the colonisation of pathogenic germs [12].
The prebiotic effect of Lactoferrin consequently has an inhibitory effect on the pathogenic components of the microbiome, and a stimulating effect on the symbionts. The exact mechanism of this growth stimulation has not yet been fully clarified and further research is needed [10].