When gut microbiota decreases, the connection between "gut and overall health" is disrupted, increasing the risk of various diseases.

Based on scientific research, we have summarized the most commonly occurring diseases.

1. Irritable Bowel Syndrome (IBS)

  • Cause: Decreased beneficial bacteria weaken the barrier function, leading harmful bacteria to produce excess gas, causing abdominal pain, diarrhea, and constipation.

  • Symptoms: Abdominal bloating, relief of pain after bowel movements, alternating constipation and diarrhea.

  • Solution: Supplementing with probiotics (such as Lactobacillus) and increasing dietary fiber intake.

2. Inflammatory Bowel Disease (IBD: Crohn's Disease, Ulcerative Colitis)

  • Cause: Lack of beneficial bacteria leads to failure in regulating intestinal inflammation → immune cells attack the intestinal mucosa.

  • Symptoms: Persistent diarrhea, blood in stool, weight loss.

  • Research findings: It has been confirmed that IBD patients have significantly lower levels of Bifidobacterium in their intestines.

3. Obesity and Metabolic Syndrome

  • Cause: When beneficial bacteria decrease, fat breakdown efficiency decreases, and inflammatory substances increase → leading to insulin resistance.

  • Mechanism:

    • Harmful bacteria secrete enzymes that "promote fat absorption" → weight gain.

    • Increased blood toxins due to leaky gut syndrome → chronic inflammation.

  • Solution: Improve gut environment with high-fiber diets and fermented foods.

4. Autoimmune Diseases (Rheumatoid Arthritis, Type 1 Diabetes, etc.)

  • Cause: Beneficial bacteria fail to act as "balance regulators" for immune cells, leading to excessive immune responses.

  • Research:

    • When beneficial bacteria are lacking, Th17 cells (which cause excessive inflammation) increase.

    • In contrast, Treg cells (immune regulators) are activated by beneficial bacteria.

5. Depression and Anxiety Disorders

  • Cause: Gut microbiota produces 90% of serotonin (the happiness hormone). Decreased beneficial bacteria → neurotransmitter imbalance.

  • Symptoms: Apathy, insomnia, decreased concentration.

  • Solution: Combining probiotics and omega-3 intake helps brain health.


The role of lactic acid bacteria, a type of gut microbiota in the human body, is much more diverse than expected. It helps suppress the growth of harmful bacteria, enhances immunity, aids digestion, and influences various metabolic processes. Because of the beneficial effects of lactic acid bacteria on the body, many people consistently take probiotics or fermented foods.

If you are concerned about your gut health, it is also good to frequently consume fermented foods (such as kimchi, cheonggukjang, yogurt) or consider probiotic supplements. By maintaining a consistent diet and continuing to consume lactic acid bacteria, you can experience positive changes not only in your gut but also in your overall body condition.

Today, we briefly looked at lactic acid bacteria and lactobacillus. How about checking your diet and lifestyle habits to ensure lactic acid bacteria can be a part of your daily life?