For many people trying to be healthier, choosing between Yakult and kefir can be confusing. Both are probiotic drinks that have grown in popularity for their effects on gut health, but which one is better?
This piece looks at the key differences between Yakult and kefir so you can decide which suits you. We’ll cover what each drink is, their ingredients and nutrition, taste, probiotics, possible side effects, and overall benefits.
What is Yakult?
Yakult is a fermented milk drink from Japan, created in the 1930s. It uses a specific strain of bacteria called Lactobacillus casei Shirota, known for its probiotic effects. Yakult is sold in small bottles and is usually marketed as a daily probiotic to help digestion and support the immune system. Its flavor is sweet and citrusy with a hint of vanilla.
Ingredients: water, skimmed milk (reconstituted), glucose-fructose syrup, sugar, maltodextrin, flavourings. Contains L. casei Shirota. When refrigerated, Yakult has about 30 billion L. casei Shirota per 100 ml (about 20 billion per 65 ml bottle).
What is kefir?
Kefir is also a fermented milk drink but has been consumed for centuries in the Caucasus region. It’s made by adding kefir grains—a mix of yeast and bacteria—to milk. Kefir usually contains many probiotic strains, such as Lactobacillus acidophilus, Streptococcus thermophilus, and Bifidobacterium bifidum. It’s tangy and slightly fizzy and can be drunk plain or used in smoothies.
Plain kefir’s ingredients are simple: pasteurised cow’s milk fermented with live kefir cultures. Flavoured versions often include added sugar and flavourings.
Are Yakult and kefir the same?
No. Both are probiotic fermented milk drinks, but they differ in how they’re made and what they contain. Yakult uses a single, specific bacterial strain (L. casei Shirota), while kefir is fermented with kefir grains and contains many different strains of bacteria and yeasts. Yakult typically has added sugar; traditional plain kefir does not.
Nutritional content
Yakult (per 100 ml)
– Energy: 66 kcal
– Fat: 0 g (saturates: 0 g)
– Carbohydrates: 15.4 g (sugars: 13.6 g)
– Protein: 1.3 g
– Salt: 0.04 g
Yakult (per 65 ml bottle)
– Energy: 43 kcal
– Carbohydrates: 10 g (sugars: 8.8 g)
– Protein: 0.8 g
Unflavoured kefir (per 100 ml)
– Energy: 59 kcal
– Fat: 2.9 g (saturates: 2.1 g)
– Carbohydrates: 4.6 g (sugars: 2.8 g)
– Protein: 3.5 g
– Salt: 0.1 g
Both drinks are low in salt. Yakult is fat-free, while plain kefir contains some fat. Yakult has more carbs and sugars, which raises its calorie count slightly. Kefir provides more protein per 100 ml. Also, kefir’s nutrition varies by brand and flavour, while Yakult comes in a standard 65 ml bottle.
Probiotic content
Yakult contains only Lactobacillus casei Shirota, a well-studied strain that resists stomach acid and bile, helping it survive to reach the intestines. It’s linked to benefits for digestion, immunity, and some studies suggest effects on IBS symptoms, infections, and even mental well-being.
Kefir usually contains a mix of many probiotic strains—often 30 or more—including Bifidobacterium, Lactobacillus acidophilus, L. casei, and L. rhamnosus, plus various yeasts. These strains can support gut health and immune function, and some are helpful for specific issues: for example, L. acidophilus and L. rhamnosus are often noted for easing IBS symptoms, L. casei can help with constipation, and some strains may help prevent or treat certain infections. The exact mix depends on the kefir type and brand.
Effectiveness for gut health
Research shows that probiotics in both Yakult and kefir can help balance gut bacteria, reduce harmful microbes, and support digestion and immune health. How well they work varies by the person and the specific strains involved. Diet and lifestyle—like fibre intake and exercise—also play a big role in gut health.
Other potential benefits
Beyond gut health, Yakult’s L. casei Shirota has been linked in some studies to reduced belly fat and improved cholesterol levels. Kefir may boost absorption of vitamins and minerals, and it’s a good source of calcium and B vitamins. Both drinks have been associated in some research with improved mood and reduced stress, though results vary and more study is needed.
Which is better for you?
There’s no one-size-fits-all answer. Yakult is a convenient, mildly sweet drink with a single, well-researched probiotic strain—good if you want something easy to find and drink daily. Keep in mind it has added sugar. Kefir offers a wider range of probiotic strains and more protein; it’s more natural and versatile but can taste tangier and comes in varied brands and flavours.
Both can be useful additions to a healthy diet and may help support gut health. Choose based on your taste, dietary needs (like sugar or fat limits), and the kinds of probiotic benefits you’re after.