What Yogurt Has Lactobacillus casei Shirota In It? Unveiling Yakult's Unique Probiotic

December 10, 2025 •

4 min read

The strain of beneficial bacteria known as Lactobacillus casei Shirota was discovered by a Japanese scientist in 1930. When searching for what yogurt has this specific probiotic, you will find it is actually contained in the fermented milk drink Yakult, not conventional yogurt. This unique strain has been fortified specifically for this single, well-known product.

Quick Summary

The probiotic strain Lactobacillus casei Shirota is exclusively found in the fermented milk drink Yakult. Traditional yogurts typically use different cultures, a key distinction for consumers focusing on specific bacterial strains for gut health.

Key Points

Yakult is the answer: The Lactobacillus casei Shirota strain is found exclusively in Yakult, a fermented milk drink, not traditional yogurt.
Yakult vs. Yogurt: Traditional yogurt relies on Lactobacillus bulgaricus and Streptococcus thermophilus for fermentation, and while some add other probiotics, they lack the specific Shirota strain.
Scientifically Backed Benefits: The LcS strain in Yakult has been scientifically shown to reach the intestines alive, supporting digestion, immunity, and managing stress symptoms.
Other Yogurt Brands: Many other brands like Activia, Chobani, and FAGE contain different beneficial probiotic strains, such as L. acidophilus or other L. casei strains.
Diversify Probiotics: For comprehensive gut health, consider incorporating a range of fermented foods like kefir, homemade curd, sauerkraut, or kimchi, in addition to Yakult or specific yogurts.
Strain Specificity Matters: The health benefits of probiotics are strain-specific, meaning a benefit observed with one strain (like Shirota) does not necessarily apply to others.

The Unique Source of Lactobacillus casei Shirota

Developed by Dr. Minoru Shirota in 1930, the Lactobacillus casei Shirota (LcS) strain is the centerpiece of the famous probiotic drink, Yakult. After isolating and strengthening this unique lactic acid bacteria, Yakult Honsha was created to commercialize and distribute it, first introduced in 1935. LcS is specially cultivated to be more resilient than many other probiotic cultures, allowing it to survive the harsh digestive environment of the stomach and reach the intestines alive. This survivability is key to its efficacy in providing health benefits to the host's gut. Yakult is a sweetened, fermented dairy drink, distinct from traditional yogurt, which is why it holds the exclusive claim to this specific and extensively researched probiotic strain.

Yakult vs. Traditional Yogurt: A Probiotic Perspective

Many people mistakenly assume Yakult is a type of yogurt due to its dairy base and probiotic content. However, there is a fundamental difference in how they are cultured and the specific bacterial strains they contain. Traditional yogurts are fermented using a specific set of starter cultures, primarily Lactobacillus bulgaricus and Streptococcus thermophilus, as per standards from organizations like the National Yogurt Association. While many yogurts, like FAGE or Chobani, do add additional probiotic strains such as Lactobacillus acidophilus or Lactobacillus casei, they do not contain the specific Shirota strain. This difference in bacterial composition is what separates Yakult from other probiotic dairy products on the market.

Comparison: Yakult vs. Traditional Yogurt


Feature	Yakult	Traditional Yogurt
Product Type	Fermented milk drink	Fermented dairy product
Key Probiotic	Lactobacillus casei Shirota (LcS)	Lactobacillus bulgaricus and Streptococcus thermophilus
Other Strains	Exclusively LcS	Often includes L. acidophilus, L. casei, Bifidobacterium, etc.
Consistency	Liquid drink	Semi-solid, often spoonable
Typical Sugar Content	Contains sugar (though light versions exist)	Varies widely, from very low to high
Primary Purpose	Targeted probiotic delivery	Food source providing nutrients and probiotics
Key Benefit	Scientifically-proven probiotic effect on gut	General gut health, nutrition (protein, calcium)

Health Benefits Backed by Science

The benefits of Yakult and its unique L. casei Shirota strain have been the subject of extensive scientific research. These studies show that regular consumption can lead to several health improvements:

Improved Digestion: The LcS strain has been shown to increase beneficial bacteria in the gut, helping to regulate the intestinal tract and improve stool consistency for those with constipation.
Enhanced Immunity: Studies suggest that LcS can improve immune function by increasing the activity of natural killer (NK) cells and modulating allergic responses.
Reduced Stress Symptoms: Research in medical students during exams indicated that LcS helped suppress increases in salivary cortisol levels, the stress hormone, and lowered the incidence of stress-related abdominal symptoms.
Relief from Diarrhea: LcS has been widely studied for its ability to help manage infectious diarrhea, including cases caused by Clostridium difficile.

Other Probiotics in Yogurt

If your goal is to simply increase your intake of probiotics from a yogurt product, many other options are available that contain beneficial strains, even if they don't have the specific Shirota strain. Here are some examples and what they contain:

Activia: Often contains Lactobacillus casei along with other cultures, known for its digestive health focus.
Chobani: Contains live and active cultures including Lactobacillus acidophilus and Lactobacillus casei.
FAGE Greek Yogurt: Includes Lactobacillus casei among its live cultures.
Siggi's Icelandic Skyr: Contains various active cultures, including L. casei.

When choosing a yogurt, it is important to check the nutrition label for the "Live and Active Cultures" seal to ensure you are getting beneficial bacteria.

How to Incorporate Probiotics into Your Diet

Incorporating probiotics into your daily routine is a straightforward process. A balanced diet often includes a variety of fermented foods, but some methods are particularly effective.

Daily Yakult: For those specifically seeking the Lactobacillus casei Shirota strain, consuming a bottle of Yakult daily is the most direct method.
Vary Your Yogurt: Don't rely on a single yogurt brand. Explore products like FAGE, Activia, or Chobani to get a broader spectrum of different probiotic strains.
Explore Kefir: This fermented milk drink typically contains a wider range of bacterial strains and yeast than yogurt.
Consider Other Fermented Foods: Incorporate foods like sauerkraut, kimchi, and kombucha for additional probiotic diversity.
Use Homemade Curd: Homemade curd (or dahi) is another excellent source of probiotics, offering high protein and calcium content without the added sugars of commercial products.

Conclusion: Choosing the Right Probiotic Source

To be clear, if your goal is to consume the specific probiotic Lactobacillus casei Shirota, your only commercial option is Yakult, a unique fermented milk drink. While many yogurts contain other beneficial strains of Lactobacillus casei and other bacteria, none contain the patented Shirota strain. For overall gut health, a diverse diet including various probiotic-rich foods is a powerful strategy, whether from Yakult, traditional yogurt, or other fermented sources. The key is to understand the difference between these products to make an informed choice for your specific health needs. For further scientific reading on the LcS strain's effects on gut microbiota, the National Institutes of Health provides numerous resources, including this study: Probiotic Lactobacillus casei Shirota prevents acute liver injury by reshaping the gut microbiota to alleviate excessive inflammation and metabolic disorders.

Frequently Asked Questions

No, Yakult is not a yogurt. While both are cultured dairy products, Yakult is a fermented milk drink containing the unique Lactobacillus casei Shirota strain, whereas traditional yogurt is fermented with different bacteria, such as Lactobacillus bulgaricus and Streptococcus thermophilus.

The main difference lies in the probiotic cultures and preparation. Yakult contains a unique, proprietary strain of Lactobacillus casei Shirota proven to reach the gut alive, while traditional yogurts use a different set of cultures. Also, Yakult is a liquid drink, unlike the semi-solid texture of most yogurts.

Yes, many yogurts contain the broader species Lactobacillus casei, but not the specific Shirota strain. Brands like Activia, FAGE, and Chobani list L. casei among their active cultures.

The Lactobacillus casei Shirota strain was specially fortified to survive stomach acid and bile, allowing it to reach the intestines alive and in high numbers. Extensive research backs its ability to promote digestive balance and enhance immunity.

While regular yogurt offers its own health benefits from its probiotic cultures, it does not provide the specific benefits associated with the unique Shirota strain. Different probiotic strains offer different effects.

The misconception likely arises because Yakult is a fermented milk product sold in the dairy section alongside other probiotic products like drinkable yogurts. It serves a similar function but is scientifically and culturally distinct.

The choice depends on your health goals. For targeted delivery of the specific L. casei Shirota strain, choose Yakult. For a broader nutritional profile with different cultures and high protein, yogurt or homemade curd may be preferable. Both can be part of a healthy diet.