Beneficial bacteria – the microbiota of the body and the vagina
The vaginal microbiota is a subset of the human microbiota. The unique feature of the vaginal microbiota is that it is dominated by relatively few species of “good bacteria”, which together manage and maintain the vaginal balance. It is these bacteria that provides the foundation for “the vagina’s natural defenses.”
What is a microbiota?
There is a myriad of bacteria living inside our bodies. Vital bacteria, microbes, that are essential for our good health. 100 trillion microbes – that is the number of bacteria residing in your body. Beneficial microbes live in harmony with the organs inside your body. They are mainly found in the gut, but are also present in the vagina. A microbial balance is important to preserve and through proper nutrition and treatments you can endorse the natural microflora. If the balance is upset, we may become ill.
Antibiotic treatments could upset the bacterial balance of our bodies. Apart from treating the harmful bacteria, antibiotics also negatively impacts our important microbiota. Antibiotics should therefore, only be used when there are no other options. . By avoiding antibiotics, when other options are available, we help to prevent a global health threat – the rapid development of antibiotic resistance bacteria.
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What is the vaginal microbiota?
The vaginal microbiota is only a subset of the human microbiota. The unique feature of the vaginal microbiota is that it is dominated by relatively few species of “good bacteria”, which together maintain and manage the vaginal balance. This provides the foundation for what is called “the vagina’s natural defenses.” The vaginal microbiota begins to develop immediately when a girl is born, within the first 24 hours, and by the time she reaches her first period it already resembles the bacterial composition of an adult woman.
The most common bacteria belong to the lactobacilli family. The lactobacilli are in turn partly controlled by the woman’s oestrogen levels. Genetics also play a role in the composition of the vaginal microbiota and therefore varies slightly between women in different parts of the world. Lactobacilli belong to the so-called fermentative bacteria. They produce lactic acid, which reduces the pH level of the vaginal tract and contributes to the acidic environment in the vagina. In this manner, the lactobacilli maintain the natural pH balance of the vagina. A normal vaginal pH range between 3.8 to 4.2.
genetics and varies slightly between women in different parts of the world. Lactobacilli belong to the so-called fermentative bacteria. They produce lactic acid, which reduces the pH level in the vagina and contributes to the acidic environment in the vagina. In this manner, the lactobacilli restore the natural pH balance of the vagina. A normal vaginal pH falls in the range of 3.8 to 4.2.
In addition to lactic acid, lactobacilli produce small amounts of hydrogen peroxide (H202), which together with the lactic acid, play an important role in the natural defense against infection. Hydrogen peroxide has a strong inhibitive effect on harmful bacteria. It is when the balance between the beneficial bacteria in the vagina and other bacteria, harmful bacteria, is disturbed that a dysbiosis (imbalance) occurs. This imbalance could lead to infections such as bacterial vaginosis. Infections such as bacterial vaginosis reduce the body’s defenses against other infections, such as HIV, gonorrhea, and chlamydia.
What influences the vaginal microbiota, and how does it evolve over the menstrual cycle and life of a woman?
The vaginal microbiota can be affected by internal and external factors. External factors include excessive intimate hygiene and unprotected vaginal sex. Contraceptives such as IUDs and hormonal contraceptives may also have an impact on the vaginal balance, as well as other hormonal treatments. If the microbial balance is disrupted, the imbalance can cause infections such as bacterial vaginosis.
One of the most important internal factors that influence the vaginal microbiota are the natural hormones that circulates the body. As mentioned previously, lactobacilli are the most common species in the healthy vaginal microflora. These bacteria are strongly affected by the woman’s oestrogen levels.
Among the most important internal factors that affect the vaginal microbiota and the vaginal balance are the hormones of the body. As mentioned above, the most common beneficial bacteria in the vagina belong to the lactobacilli family, and these are controlled, among other things, by the oestrogen levels which vary throughout the menstrual cycle. This in turn impacts the lactobacilli which have been shown to decrease in number during the first days of the menstrual cycle, and at the same time, the vaginal pH has been observed to increase during this period.
During pregnancy, oestrogen levels rise which directly affects the epithelial cells and the environment in the vagina. The growth of lactobacilli increases, further strengthening and stabilizing the natural defenses of the vagina.
At menopause, however, the oestrogen levels decrease, this affects the vaginal environment and could make the mucous membranes thinner and more vulnerable while reducing the amounts of lactobacilli.
Is there a need for more research in this area?
It is known that the vaginal microbiota is constantly evolving during a woman’s life, from birth, via menstruation, to menopause. However, more research in this exciting area is needed. Studies that investigate how the vaginal defense – the vaginal microbiota – can best be stimulated and maintained. Moreover, many women are affected by imbalances in the vaginal environment during menstruation, when the pH level of the vagina increases, and in some cases, this may lead to lasting imbalance in the vagina that could result in infections such as bacterial vaginosis.
Read more about bacterial vaginosis.