When you think of bacteria, what comes to mind? "Bad things"? Harmful to health?
In fact, human health is inseparable from bacteria. The internal environment of the human body is complex, with a large number of bacteria especially in the gut. Among them, the gut microbiota is closely linked to health. Its imbalance can lead to various diseases, including gastrointestinal discomfort, hypertension, hyperlipidemia, diabetes, insomnia, depression, and more.
In this issue of our popular science column, we are honored to invite Professor Dai Wenxin, Director of the Multidisciplinary Geriatrics Center and gut microbiota treatment expert at Hainan Chengmei Hospital, to introduce relevant knowledge about the gut microbiota.
The Gut Microbiota: Life and Death, Partners for Life
The gut microbiota is not innate; it is actually "foreign."
In the mothers womb, the fetus is in an almost sterile environment, and thus the fetal gut is also sterile. Within the first few days after birth, bacteria enter the newborns body through various routes, such as exposure to vaginal flora during delivery, oral intake during breastfeeding, and inhalation of airborne microorganisms. These bacteria then colonize the infants gastrointestinal tract, establishing the initial gut microbiota.
As the infant grows, the composition and structure of the gut microbiota gradually stabilize, ultimately forming a mature gut microbiota. These tiny organisms silently colonize the human body and accompany their host throughout life without notice.
The Gut Microbiota: A Vast "Microbial Library"
The human body is a vast "microbial library." These microorganisms are mainly distributed in the eyes, mouth, nasal cavity, throat, skin, gastrointestinal tract, reproductive organs, and other parts of the body, with a total weight of approximately 1.27 kg. The gastrointestinal microbiota constitutes the largest portion, accounting for about 80% of the total weight, exceeding 1 kg. It is known that the human gut hosts around 100 trillion microorganisms, with over 4,000 species of bacteria present. The total number of genes in the gut microbiota exceeds 3.3 million, which is 150 times the number of genes in the human genome.
Human gut bacteria can generally be categorized into three types:
Beneficial Bacteria
These are the "good" bacteria that are beneficial to human health, such as Bifidobacterium and Lactobacillus.
Pathogenic Bacteria
These are the "bad" bacteria that can harm human health, such as Clostridium perfringens, Pseudomonas aeruginosa, and others.
Opportunistic Pathogens
These are "neither good nor bad" bacteria. Under normal conditions, they are harmless and may offer slight benefits. However, under specific circumstances, they can cause harm and lead to illness, such as Escherichia coli, Enterococcus faecalis, Staphylococcus, and others.
Gut Microbiota Balance is Closely Linked to Human Health
01. Aid in Digestion and Nutrient Absorption
This includes the digestion of proteins, sugars, fats, iron, calcium, and vitamin D, as well as the synthesis of vitamins B, C, K, niacin, and folic acid, and the maintenance of normal gastrointestinal motility.
02. Promote Immune System Function
The microbiota consisting of Bifidobacterium, Lactobacillus, and others provides protective colonization, producing bacteriocins, organic acids, hydrogen peroxide, and other substances that block or inhibit the invasion of pathogenic or opportunistic pathogens, generating nonspecific immune effects on the intestinal mucosa. As antigens, the gut microbiota stimulates and promotes the development and maturation of the immune system, enabling the body to resist many pathogens and their toxins, thus enhancing specific immune responses.
03. Inhibit Tumorigenesis and Tumor Progression
When the microbiota is balanced, beneficial bacteria such as Bifidobacterium can degrade nitrosamines into nitrites and amines, exerting an anti-cancer effect. However, pathogens like Escherichia coli, Clostridium perfringens, Enterococcus, and Bacteroides can facilitate the formation of carcinogenic nitrosamines from nitrites and amines in food. Therefore, the role of the gut microbiota in cancer promotion or inhibition depends on which microbial populations dominate. In a healthy state, cancer-inhibiting bacteria prevail, exerting an anti-cancer effect.
04. Anti-Aging Effects
When the microbiota is balanced, it can reduce cholesterol absorption, lower toxin levels in the blood, and exert anti-aging effects. Maintaining a higher number of beneficial microbes in the gut promotes overall health. If the balance between beneficial and harmful bacteria is disrupted, illness can occur.
Protecting the Gut Environment for a Better Life
Many people may wonder, if the gut microbiota is already imbalanced, how can it be restored to a healthy state?
Nowadays, the concept of microbiota transplantation has played a significant role in the treatment of many diseases. Fecal Microbiota Transplantation (FMT) is a key method for restoring gut microbiota balance. It involves precise gut microbiota testing, disease risk prediction, targeted application of probiotic treatments, and periodic monitoring of gut flora to maintain and restore a healthy gut ecosystem.
What does "precision" mean? First, through precise testing and professional evaluation, inflammation is controlled and harmful bacteria accumulated over the years are isolated. Second, a microbiota from 4-17-year-old children is transplanted into the patients gut to rebuild a new gut microbiota. Third, probiotics, prebiotics, and other nutrients are supplemented to help restore normal physiological functions of the gut.
Expert Introduction
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Editor | Huang Fei