Skin bacteria that protect us?
The flu season is here and I hear that we should wash our hands as much as possible to help prevent spread of flu viruses. My skin is already irritated and I am afraid to make things worse. Do we need to have skin with no bacteria or viruses or are some of the bacteria good for us?
We’ve all heard about good digestive bacteria . Some of us actively try to manage our intestinal flora with a variety of supplements. Why would our skin be any different?
Is it possible that skin bacteria are good for us? In fact, there is more and more evidence that human skin bacteria are necessary for life and may be required for optimal skin and body functioning. In the next few paragraphs, I will discuss recent discoveries about our need to keep good skin bacteria happy.
People associate bacteria with four D’s: dirt, disease, death and decay. This may be true, but I think it’s time to improve bacterial public relations image, as we would not be able to live without them.
Humans are a walking sophisticated ecosystem. There are greater than 10 times as many microbial organisms living on us and in us than our own cells. Recent studies have identified more kinds of different bacteria living on our skin than previously thought. Although only few patients were tested, the researchers found more than 240 distinct species of bacteria living on the skin of healthy volunteers. Germophobes should not panic. These bacteria interact with our skin and are involved in wound healing and inflammation. A great majority of these bacteria are harmless to us under normal circumstances and, in fact, are necessary for our healthy living.
Here are some facts about skin bacteria:
- Our skin is covered with bacteria – some areas have more than others. Our skin topography mostly consists of what could be described as deserts. The top layer of the skin blocks water loss from our body resulting in relatively dry conditions. As is the case with deserts – not many things live there including bacteria. At the same time, there are areas of increased moisture such as creases in the skin, nose, underarms, groin as well as areas between our toes. In general, moister areas are so lush that many more bacteria make it home.
- Bacteria controls pieces of skin real estate – different bacteria live in different places. There is no such thing as a sterile piece of the skin. If good and harmless bacteria are removed, there is a possibility of bad bacteria moving in and occupying that space. The key is to maintain good bacteria and prevent bad bacteria from moving in.
- Skin bacteria modulate inflammation – a recent study by Dr. Gallo and colleagues identified an important interaction between normal skin bacteria and our immune system. It turns out that bacteria secretions are important for preventing excessive inflammation. We know that some inflammation is good when wound healing is needed but excessive inflammation could be as dangerous as the injury itself.
- Different people have different bacteria – our bodies are like a bacteria zoo and our skin is no different. We have resident bacteria (bacteria that live on our skin most of the time) and transient bacteria (bacteria that are there one time and not the other.) Over 50% of skin bacterial species belong to four genera (similar kind of bacteria) that represent more or less constant residents of the human skin. One study found that over 70% of bacterial species were unique to individual subjects and that each person’s bacteria changed over time likely related to diet, clothing, climate seasons and skin care.
- Our skin is excellent protector from bad bacteria – it has multiple defence mechanisms ranging from the impenetrable outer layer to the specific antimicrobial peptides and lipids. When foreign bacteria are applied to normal skin, they rapidly decrease in number and eventually are taken over by resident bacteria. The trouble happens when there is maceration (resulting from prolonged skin contact with moisture) or occlusion (no or decreased contact with air.) In these circumstances, the normal balance of the skin bacteria is disturbed resulting in more favourable conditions for bacteria to penetrate the skin. Healthy skin resists these invaders and is the best way to prevent infections.
- Over-washing is more dangerous than under-washing – most cleansing removes bad and good bacteria and in some cases can cause more harm than good. When strong cleansers are used, their ingredients (natural or not) not only remove bacteria but also disrupt normal skin barrier. We have all experienced it – our skin gets dry and forms fine cracks. These cracks are portals for bacteria and viruses entry. Cleaning product commercials like you to think that the best skin is sterile and bacteria free – nothing can be further from the truth. Let’s remember that flues and colds are caused by viruses and NOT by bacteria. Wouldn’t it be nice to know on the bottles of cleansers how many viruses it kills? We need good bacteria and most of the skin bacteria are GOOD. Is regular soap and water enough? I think you know the answer by now.