Yakult is a Probiotic Drink Containing Lactobacillus casei Shirota

Probiotic milk drinks such as Yakult are not new. In fact we humans have been drinking them for around 2,000 years. Traditionally probiotic milks or fermented dairy drinks, as they are also known, were homemade. Today these drinks are also produced commercially in specialist sterile environments. One of the most widely known probiotic milk brands internationally is Yakult. Worldwide over 28 million people in 32 different countries consume this product. It’s most popular in Asia, followed by Europe. It’s still relatively new to the United States and is not yet available in every state but its popularity is growing with sales of around 100,000 bottles per day as of January 2010.


Like most of the other fermented dairy drinks on the market, Yakult is sweetened. The sugar and glucose contained in the product are intended to counterbalance the sour taste of the probiotic cultures. They also preserve the product and are supposed to serve as food for the probiotic bacteria. The milk and sugar, which caramelize during the heating process, give the product its brownish color.

Yakult is not a

probiotic yogurt. It contains a different probiotic bacterium from probiotic yogurts. This bacterium is known as Lactobacillus casei Shirota.

The product is available in 2.7 ounce (80ml) mini bottles, each containing one single serving. Each bottle contains an approximately 8 billion colony forming units (CFUs)1 of probiotic bacteria. Its ingredients are:

  • Water

  • Sugar

  • Skim milk powder

  • Glucose

  • Natural and artificial flavors

  • Lactobacillus casei Shirota

It is suitable for the old and young alike as well as for pregnant women.

Scientific Evidence

Yakult is the only probiotic product in the world containing the bacterium Lactobacillus casei Shirota, which is named after the Japanese microbiologist, Dr Minoru Shirota, who first cultured it. According to the company that produces Yakult, Yakult Honsha Co Ltd, Lactobacillus casei Shirota is one of the most studied probiotic strains. Indeed the company even has its own research facility. In scientific research carried out by the company itself as well as by other institutions, Lactobacillus casei Shirota has been shown to:

  • Reduce the incidence of acute diarrhea2.
  • Improve stool consistency and constipation 3,4.

  • Increase beneficial bacteria (bifidobacteria) and decreases harmful bacteria (enterobacteriaceae)5.

  • Survive transit through the gastro-intestinal tract. Indeed the scientist who first cultured Lactobacillus casei Shirota set out to find a tough bacteria that would survive the acid conditions of the stomach6.

Pros and Cons

In terms of its advantages, the product is very convenient in terms of both size and storage – it can be kept out of the refrigerator for a short while so it suitable to take with you as a snack or part of your lunch.

It also contains a good number of beneficial bacteria per serving, comparable to many of the lower strength probiotic supplements on the market.

It is gluten free and suitable for vegetarians and what's more it is good value. The suggested US retail price for a multipack of five drinks is $2.99USD.

On the downside though, the product does contain rather a lot of sugar. If you are diabetic you will need to take care with this product. If you prefer the idea of sugar free probiotic milk, you can always make your own. Have a look at our recipes for instructions on how to do so as well as our page on types of yogurt starter for information on obtaining the starter cultures required. A few recipes for fermented milk drinks can also be found in the book "Nourishing Traditions" by Sally Fallon.

Finally in the USA the product is available only in multipacks of five, making it impossible to buy just one to try.

Where Can I Buy It?

The product is available in the refrigerated dairy section of many major supermarkets and other retail stores including Wal-Mart and Safeway. It is presently available only in California, Nevada, Arizona, Texas, Colorado, and New Mexico. However, a US production plant is in construction and production is due to start in 2012. This plant will supply the current sales areas as well as new ones so availability should improve from 2012.


1.Colony forming units (CFUs) are a measurement of the number of viable bacteria contained in a product.

2.Sasoaka, I; Daily Intake of 'Yakult' Is Efficacious in Reducing Incidence of Acute Diarrhea in Young Children; Collaborative Study with India National Institute of Cholera and Enteric Diseases, August 2010

3.Koebnick, C.; Wagner, I.; Leitzmann, P. et al. Probiotic Beverage Containing Lactobacillus casei Shirota Improves Gastrointestinal Symptoms in Patients with Chronic Constipation; Canadian Journal of Gastroenterology; 2003; 17: 655-659

4.Matsumoto, K. et al; The Effects of a Probiotic Milk Product Containing Lactobacillus Casei Strain Shirota on the Defecation Frequency and the Intestinal Microflora of Sub-optimal Health State Volunteers: A Randomized Placebo-controlled Cross-over Study; Bioscience Microflora; 2006: 25, 39-48

5.Matsumoto, K. et al; The Effects of a Probiotic Milk Product Containing Lactobacillus casei Strain Shirota on the Defecation Frequency and the Intestinal Microflora of Sub-optimal Health State Volunteers: A Randomized Placebo-controlled Cross-over Study; Bioscience Microflora; 2006:25, 39-48

6.Norikatsu Yuki et al; Survival of a Probiotic, Lactobacillus Casei Strain Shirota, in the Gastrointestinal Tract: Selective Isolation from Faeces and Identification using Monoclonal Antibodies; Yakult Central Institute for Microbiological Research 1998

Return from Yakult to Probiotic Foods

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