What happens if you eat lactobacillus? A guide to the benefits and considerations

October 24, 2025 •

4 min read

According to the National Institutes of Health, trillions of bacteria reside in the human gut, playing a crucial role in overall health. When you eat lactobacillus, a well-known probiotic, you are either supplementing your body's natural supply of beneficial bacteria or introducing new ones to support a healthy, balanced microbiome.

Quick Summary

Consuming Lactobacillus introduces beneficial bacteria to your gut, supporting digestion and immune function. For most healthy individuals, it's safe, though mild and temporary side effects are possible.

Key Points

Supports Digestion: Consuming Lactobacillus aids digestive health by balancing gut flora, which can help with diarrhea and IBS symptoms.
Boosts Immunity: Lactobacillus can enhance immune function by interacting with the body's immune system, potentially supporting the body's defenses.
Possesses Strain-Specific Effects: The health effects of Lactobacillus can vary significantly depending on the specific strain consumed, so results are not universal.
Risk for Vulnerable Groups: Individuals with weakened immune systems, central lines, or serious illnesses are at a rare but higher risk of infection and should consult a doctor.
Naturally Found in Fermented Foods: Excellent dietary sources of Lactobacillus include yogurt, kefir, and sauerkraut, offering a natural and safe way to consume probiotics.
Imbalance can cause Cytolytic Vaginosis: In the vaginal microbiome, an imbalance of Lactobacillus can cause cytolytic vaginosis, a condition that is often misdiagnosed.
Side Effects are Generally Mild: For healthy people, potential side effects are typically minor digestive issues like gas and bloating that often resolve with time.

The Role of Lactobacillus in the Human Body

Lactobacillus species are a type of 'friendly' bacteria, commonly used in fermented foods like yogurt, kefir, and sauerkraut. As a probiotic, Lactobacillus helps regulate your digestive system by maintaining a balance between 'good' and 'bad' bacteria. By producing lactic acid, Lactobacillus can create an environment that inhibits the growth of harmful bacteria. However, the effects are strain-specific, and the potential health benefits can vary between products.

Beneficial Effects of Eating Lactobacillus

Eating Lactobacillus can have several positive effects on your health, particularly for your digestive and immune systems.

Improved Digestive Health: Lactobacillus is widely used to manage and prevent various forms of diarrhea, including those associated with antibiotic use. It helps restore the gut flora, reducing symptoms and supporting faster recovery. It may also help alleviate symptoms of irritable bowel syndrome (IBS), such as abdominal pain and bloating.
Enhanced Immune Function: By interacting with the immune system, Lactobacillus can help bolster the body's defenses. Some studies suggest that certain Lactobacillus strains may support immune function.
Vaginal Health: Lactobacillus is the most common bacteria in a healthy vaginal microbiome, where it produces lactic acid to help maintain a balanced environment. As a probiotic, it may help support vaginal health.
Potential for Supporting Cholesterol Levels: Some research indicates that consuming yogurt fortified with Lactobacillus acidophilus may help support healthy cholesterol levels. However, results have been mixed, and this effect may depend on the specific strain and combination with other factors.

Potential Side Effects and Risks

While generally safe for most people, consuming Lactobacillus can cause some side effects, especially when first introduced to the diet.

Common Side Effects: The most common reactions are mild and digestive-related, including gas, bloating, and stomach upset. These symptoms often subside within a week or two as the body adjusts.
Risks for Vulnerable Individuals: For people with weakened immune systems (e.g., due to chemotherapy, HIV), those with central venous catheters, or those who have recently had surgery, there is a small risk of serious infection, including bacteremia. It is crucial for these individuals to consult a healthcare provider before starting any probiotic.
Lactobacillus Imbalance: In rare cases, an imbalance of Lactobacillus in the vaginal microbiome can occur, causing a condition called cytolytic vaginosis. Symptoms mimic a yeast infection, but antifungal treatments are ineffective. In this case, probiotic intake may need to be adjusted.

Sources of Lactobacillus

Lactobacillus is available through both food and supplements.

Fermented Foods: A wide variety of fermented foods are excellent natural sources of Lactobacillus.
- Yogurt
- Kefir
- Sauerkraut
- Kimchi
- Miso
- Sourdough bread
- Some cheeses
Probiotic Supplements: These are available in capsules, tablets, powders, and liquid forms. They typically provide a concentrated amount of specific strains.

Comparison of Lactobacillus Sources


Feature	Dietary Sources (e.g., Yogurt, Kefir)	Probiotic Supplements
Naturalness	Present naturally within the food matrix.	Isolated strains in concentrated form.
Concentration	Varies widely and is less controlled.	More standardized, with a specified measure of beneficial bacteria.
Strain Variety	Often contain multiple strains, but may not be specified.	Typically list specific, tested strains.
Side Effects	Less likely to cause significant side effects due to lower concentration.	Can cause mild digestive upset when first started due to higher concentration.
Suitability	Safe for most healthy individuals; good for daily maintenance.	Useful for potentially targeting specific conditions; requires careful management.

Finding the Right Balance

For most healthy adults, consuming Lactobacillus through fermented foods is a safe and beneficial way to support gut health. However, if you are considering supplements to support a specific health issue, such as IBS or antibiotic-associated diarrhea, discussing it with a healthcare professional is wise. The supplement market is not strictly regulated, and the potency and quality of products can vary. A doctor can help determine the appropriate approach for your needs, minimizing potential side effects.

Conclusion

Eating Lactobacillus is generally safe and offers numerous health benefits for digestion and immunity, particularly when obtained through fermented foods. While minor side effects like gas and bloating can occur, they are usually temporary. The most significant risks are reserved for vulnerable populations with compromised immune systems, who should always seek medical advice before taking probiotics. For most, a balanced diet rich in fermented foods is an excellent strategy for maintaining a healthy and diverse gut microbiome. For those considering targeted supplementation, consulting a healthcare professional is the safest path forward.

For more information on the functional roles of different Lactobacillus species in health and disease, you can refer to relevant academic literature, such as research published by the National Institutes of Health.

Frequently Asked Questions

For most healthy individuals, eating Lactobacillus is safe. However, people who are immunocompromised, have central lines, or are critically ill face a rare but serious risk of infection and should consult a healthcare provider before use.

Yes, many fermented foods are natural sources of Lactobacillus, including yogurt, kefir, and unpasteurized sauerkraut. A balanced diet incorporating these foods is a great way to consume beneficial bacteria.

The most common side effects are mild digestive issues such as gas, bloating, and stomach upset. These typically appear when you first start or increase your intake and often resolve as your body adjusts.

Yes, studies show that Lactobacillus can help prevent and support recovery from various types of diarrhea, including antibiotic-associated diarrhea.

In individuals with a weakened immune system, there is a very small but higher risk of serious infection, such as bacteremia, if the bacteria from the gut or supplements enter the bloodstream.

Cytolytic vaginosis is a condition caused by an imbalance of Lactobacillus in the vaginal microbiome. This can cause symptoms similar to a yeast infection, but it requires different management. Taking a break from Lactobacillus-containing probiotics is often recommended.

There is no universally set 'right amount,' and it can vary greatly by product. For supplements, there is typically a specified measure of beneficial bacteria. It's best to follow product instructions or consult a doctor.

While a fatal outcome is not expected, consuming a very large amount of probiotics can increase mild digestive side effects like gas and bloating. The excess bacteria will likely be passed out of the body.