There is the following reality regarding modern science:
1. All resident bacteria in the human body cannot be classified as good or bad.
2. There is no technology that can classify organisms as good or bad, and control or reduce certain bacteria while growing or proliferating others.
It is said that many bacteria, including those that have not yet been named, live on our skin. In modern science, while the identification of the skin resident bacteria that cause trouble is progressing, not all skin resident bacteria, including those that have not been named yet, can be distinguished as being good or bad for the skin.
This is because, in the case of skin, there is no scientific evidence to deny the possibility that even what are considered good resident bacteria may act adversely to the skin depending on conditions (also called opportunistic bacteria), or that the bad resident bacteria may act to the benefit of the skin, such as by protecting the skin against the invasion of bacteria from outside. There is no evidence, and the details of resident bacteria have not been fully studied or clarified.
Bacteria are classified into gram-positive bacteria, gram-negative bacteria, fungi, etc., and not classified as good or bad. There is no latest technology to classify organisms as good or bad.
Just like on humans, animals, insects, and other living things, using poisons, insecticides, and fungicides can act on all organisms, including bacteria, at the same time.
The same goes for the opposite. With the recent boom in lactic acid bacteria, interest in fungi and bacteria in the beauty industry has increased. However, even if we want to grow and proliferate beneficial bacteria that are good for the skin or have good effects on the human body by focusing on “good bacteria,” all bacteria, including those that are unfriendly, increase at the same time.
Furthermore, humans and animals have acquired the physiological function of secreting sebum necessary for protecting their own skin and maintaining health in the course of evolution. The sebum secreted by the sweat glands contains ingredients that keep the pH level of each person’s skin optimal and help maintain a good balance of skin resident bacteria.
They are called fatty acids and are components contained in human sebum, animal oils, and plant oils such as olive oil. For this reason, there are cosmetic products all over the world that contain plant and animal oils that contain these fatty acids in the hope of replenishing sebum and keeping skin in good condition.
While fatty acids, which are components of sebum, suppress unfriendly bacteria such as Staphylococcus aureus and favor beneficial bacteria such as Staphylococcus epidermidis, it is part of the basic physiological function (the same as saliva, which maintains the balance of resident bacteria by keeping the inside of the mouth slightly acidic) that is necessary for animals to maintain the skin slightly acidic and keep a good balance of resident bacteria. Therefore, it is quite natural that beneficial bacteria are favored and unfriendly bacteria are controlled. (Otherwise, your skin would become overwhelmed by unfriendly bacteria, which can lead to skin problems.)
Additionally, there is little scientific evidence as to why applying cosmetic products containing fatty acids and plant and animal oils, which are nutrients for all bacteria, improves the beneficial bacterial count while keeping down the unfriendly bacterial count, or whether it is always that way. It has also been considered impossible to obtain actual clinical effects.
In addition, the sebum components and the optimum fatty acid composition differ from person to person, and so does the composition of resident bacteria in and on the skin. It is not scientifically realistic in terms of flora studies to expect that replenishing fatty acids to the skin (this is to say if saliva components were added to your mouth) decreases the unfriendly bacterial count or increases the beneficial bacterial count.
(However, our research team also believes that fatty acids are very beneficial for the skin, so we conducted research and development of SPACE Cosme as a skincare product line that supplements the functions of sebum and contains plant ingredients rich in fatty acids.)
The world’s most advanced lactic acid bacteria research currently shows the following about peptides from lactic acid bacteria that can selectively control certain bacteria.
Lactic acid bacteria produce peptides that suppress (harmless to themselves) bacteria that are enemies to them for their proliferation. The peptides produced by lactic acid bacteria vary depending on the type, ranging from those with a narrow spectrum (range) to those with a broad spectrum.
For example, Nisin A has the widest spectrum and controls most gram-positive bacteria. However, Nisin A does not act on gram-negative bacteria or fungi. (The invention of Neonisin-e®︎ by a national research institute achieved the world’s first preparation that acts on gram-positive bacteria, gram-negative bacteria, candida, etc.)
On the other hand, peptides with a narrow antimicrobial spectrum only inhibit certain gram-positive bacteria (gram-positive bacteria closely related to the producing bacteria).
It’s not impossible to say that a bacterium or bacteriocin selectively inhibits a particular unfriendly bacterium, but unfortunately, it also acts on related gram-positive bacteria.
No single substance has yet been discovered in the world that acts on Staphylococcus aureus alone. It is impossible to get rid of “bad bacteria” from among all bacteria.
Likewise, it is also impossible to just nourish or proliferate the beneficial bacteria. While we understand people’s desire to seek beauty and hydrating effects by focusing on the presence and action of beneficial on the skin and cultivating and increasing them, unfortunately, efforts to do so will also increase unfriendly bacteria.
For example, providing nutrients such as oligosaccharides and dietary fiber to lactic acid bacteria also nourishes and consequently proliferate unfriendly bacteria.
In fact, it is difficult for new beneficial bacteria from outside to colonize the human body. Also, because beneficial bacteria cannot be selectively nourished out of all resident bacteria on each person, the bacteria flora composed of both beneficial and unfriendly bacteria does not change after all. Providing nutrients can also proliferate relatively strong unfriendly bacteria, which can lead to their further proliferation.
In other words, the latest technology has not achieved the selective control or action on either type of bacteria.
Living things on Earth, including us humans, support, complement, and act on each other and co-exist in balance. None of them exist in a meaningless way, and in a situation where science has not made progress in elucidating their functions and interactions, we cannot label them as good and bad, excellent and inferior.
In addition, even among the same human race, the bacterial composition on the skin has been reported to differ according to ethnic group, family, and individual according to heredity and living environment. It is impossible to distinguish between beneficial and unfriendly bacteria over several hundred kinds of skin resident bacteria for each person.
The bacteria and flora that we have on our skin and in our intestines are not present from our birth. They are inherited from parents who live in the same environment, who share the same genes, through cheek-rubbing and saliva contact when we are infants. The bacteria composition that is genetically and environmentally optimal for each individual protects the body.
Like human beings, other living things are good and bad for certain people and society, but they are born and exist because they are necessary, and they live and co-exist with their own individuality. We can’t see them, but this also applies to bacteria.
Skin problems are caused by the “overgrowth” of Staphylococcus aureus and acne-causing bacteria, which live on the skin as resident bacteria and are typically bacteria that usually do not cause problems.
Our research team studies how to safely approach bacteria that exist as resident bacteria on the skin but overgrow and cause skin problems and how to keep the skin healthy and supple.
For more information, please read the thesis collection.