Beneficial microorganisms for teeth, skin, and hair have been identified.

Trillions of bacteria, viruses, and fungi inhabit the human body, collectively referred to as the microbiota. A person's health largely depends on the relationship between these microorganisms and their host. The microbiota plays a crucial role in metabolism, the proper functioning of the digestive, immune, endocrine, cardiovascular, and central nervous systems. There is also a connection between the microbial community residing in the body and levels of cholesterol, blood glucose, and body weight. It's no surprise that the microbiota is often referred to as another important "organ" of the human and animal body.

Imbalance in microbial communities disrupts vitamin production, suppresses local immunity, and contributes to the development of many diseases. Among these are inflammatory bowel diseases, obesity, type II diabetes, acne, and many others. Scientists have found a link between the microbiota and food allergies, as certain substances produced by microorganisms influence their development.

Researchers have studied the impact of the microbiota on the state of various body systems. For example, in the oral cavity, some bacteria harm humans by promoting tooth decay, while others, on the contrary, are beneficial—they participate in nutrient metabolism, hinder the reproduction of pathogenic microbes, improve the synthesis of vitamins B, K, and C, and enhance the absorption of vitamins D, E, B9, and B3.

When the balance is disrupted, including due to smoking and alcohol consumption, issues can arise not only with teeth but with the entire body. For instance, if bacteria from the mouth enter other organs during periodontitis, this can play a role in the development of cardiovascular diseases, rheumatoid arthritis, stroke, inflammatory bowel diseases, appendicitis, and other conditions.

Scientists recommend managing the microbiota through proper personal hygiene, diet, stress reduction, adherence to work and rest schedules, and physical activity. However, they advise caution with hygiene practices. The authors noted that people have long associated this concept with the total elimination of microbes. In the past, this approach was somewhat justified. For example, when obstetricians in the 19th century noticed that handwashing helped combat postpartum infections, maternal mortality rates significantly decreased. However, a distortion occurred—hygiene became associated with sterilization, which harms both beneficial and harmful microorganisms.

“Currently, some manufacturers advertise mouthwashes and soaps that kill up to 99.9% of microbes. Such products can disrupt the natural microbiota,” explained Professor Chikindas. For instance, some mouthwashes suppress the growth of bacteria by altering nitric oxide metabolism, which, as studies show, may be linked to the onset of type II diabetes.

Probiotics—beneficial microorganisms obtained from the body of a healthy person, animal, or food product—can help restore balance, the scientists noted. For example, lactobacilli and bifidobacteria have long been used to treat conditions such as intestinal diseases and women's health issues. However, there are many areas that remain under-researched, yet hold great potential in the prevention and treatment of a wide range of ailments, according to the authors of the scientific article.

This also applies to oral hygiene. For instance, mouthwashes containing probiotics and postbiotics (byproducts of microbial activity that positively affect human health) could help address several issues at once. Certain strains reduce bad breath, gum inflammation, suppress symptoms of streptococcal angina and oral thrush, and also possess anti-inflammatory properties.

One study showed that among 50 female students who consumed 200 grams of probiotic yogurt daily and used xylitol chewing gum (a prebiotic that positively affects probiotic microorganisms) three times a day after each meal, there was a significant reduction in the levels of bacteria responsible for tooth decay. According to other scientific studies, milk enriched with Lacticaseibacillus rhamnosus microorganisms reduced the risk of tooth decay in preschool children and made non-surgical treatment of chronic periodontitis more effective.

Furthermore, certain probiotics can be considered potential alternatives to antibiotics, as they can displace pathogenic bacteria without killing the "good" microbiota. As scientists explained, some microorganisms, including Streptococcus salivarius, can produce bacteriocin-like inhibitory substances (BLIS) that support immune system function, help prevent tooth decay, periodontitis, halitosis, and various inflammatory processes.

Probiotic bacteria can also combat pathogens that cause skin diseases, including acne, atopic dermatitis, and psoriasis—several studies have shown positive results in patients with allergic and other conditions. This applies to both topical agents and oral supplements, as the gut microbiota also influences skin health. For instance, a strain of Micrococcus luteus derived from human skin acts against several microbes that cause skin pathologies. Additionally, it limits the growth of odor-causing organisms, which can be beneficial for individuals with foot dermatophyte infections.

Probiotics and prebiotics can also be effective in combating underarm odor. Trials have shown that products containing the Lactobacillus bulgaricus strain reduce the number of bacteria that break down sweat and sebaceous gland secretions, releasing volatile odor-causing substances. In another study, a topical cream containing live Lactiplantibacillus pentosus was used to control these bacteria.

Some studies have investigated the use of soaps with probiotics containing various bacteria, including those of the Bacillus genus. These soaps showed effectiveness against pathogenic microorganisms. Such products could reduce the harmful effects of aggressive skin care agents, researchers believe.

Probiotics Lbs. paracasei in shampoos have shown promising results in improving scalp health. They helped reduce dandruff, oil secretion, and improved hair growth.

The researchers concluded that incorporating probiotics into hygiene and cosmetic products could prevent the adverse effects of their active components on the body. Additionally, the researchers noted a proven link between dysbiosis and food allergies, suggesting that the future of its therapy lies in fecal microbiota transplantation.

The authors of the article also highlighted other applications of probiotics. Several clinical studies have demonstrated a positive, albeit limited, effect of using certain bacteria in the treatment of obesity, type II diabetes, inflammatory bowel diseases, colorectal cancer, and colon cancer. “Probiotics can be delivered into the body through dietary supplements, medications, and food products enriched with microorganisms,” noted Mikhail Chikindas. Such products include dairy products enriched with microorganisms, such as yogurt or kefir, as well as juices, cereals, and infant formula.

However, the role of probiotics should not be overstated—currently, products enriched with beneficial microorganisms and dietary supplements can only be considered a complement to medication therapy, the authors of the article warned.

As Oleg Mitrokhin reported, the F.F. Erisman Institute of Public Health at Sechenov University plans to organize further research on the effects of probiotics on the body in collaboration with industrial partners, after which new-generation drugs and personal hygiene products that do not harm human microbiota and do not contain chemical compounds with adverse health effects may be developed in Russia.

The study involved: Oleg Mitrokhin, Director of the F.F. Erisman Institute of Public Health at Sechenov University, and Mikhail Chikindas, Professor of the Department of General Hygiene at Sechenov University and Rutgers University (USA). The scientific review was published in the journal Probiotics and Antimicrobial Proteins.