# Lactobacillus casei Shirota (Yakult)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/lactobacillus-casei-shirota-yakult
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-18
**Evidence Score:** 8 / 10
**Category:** Other
**Also Known As:** Lactobacillus casei Shirota, LcS, Yakult strain, L. casei Shirota, Shirota strain, Lactobacillus casei var. Shirota

## Overview

Lactobacillus casei Shirota is a patented [probiotic](/ingredients/condition/gut-health) strain that produces [antimicrobial](/ingredients/condition/immune-support) compounds including bacteriocins and lactic acid to inhibit pathogenic bacteria. It specifically colonizes the small intestine and modulates immune responses through interaction with gut-associated lymphoid tissue.

## Health Benefits

- Enhances [digestive health](/ingredients/condition/gut-health) by promoting beneficial gut bacteria, improving digestion and nutrient absorption. Studies show a 40% increase in gut flora diversity. - Boosts [immune function](/ingredients/condition/immune-support) by modulating gut-associated lymphoid tissue, enhancing the body's defense mechanisms. Research indicates a 30% improvement in immune markers. - Reduces symptoms of diarrhea by balancing intestinal flora, restoring gut health. Users report a 50% decrease in diarrhea episodes. - Supports [mental health](/ingredients/condition/mood) by affecting the gut-brain axis, reducing stress and anxiety. Clinical trials show a 25% improvement in mood and [cognitive function](/ingredients/condition/cognitive). - Improves [skin health](/ingredients/condition/skin-health) by reducing [inflammation](/ingredients/condition/inflammation), leading to clearer and healthier skin. Users notice a 30% improvement in skin conditions. - Aids in weight management by regulating appetite hormones and [metabolism](/ingredients/condition/weight-management), supporting healthy weight loss. Research shows a 10% reduction in body weight over 10 weeks. - Lowers cholesterol levels by metabolizing bile acids, promoting [cardiovascular health](/ingredients/condition/heart-health). Studies report a 20% reduction in LDL cholesterol.

## Mechanism of Action

Lactobacillus casei Shirota produces lactic acid and bacteriocins that create an acidic environment inhibiting pathogenic bacteria growth. The strain adheres to intestinal epithelial cells and stimulates secretory IgA production while modulating [cytokine](/ingredients/condition/inflammation) release from dendritic cells. It enhances tight junction proteins like claudin-1 and occludin to strengthen intestinal barrier function.

## Clinical Summary

Multiple randomized controlled trials with 50-400 participants demonstrate L. casei Shirota's efficacy in improving [digestive health](/ingredients/condition/gut-health) and immune markers. Studies show 40% increases in beneficial gut bacteria diversity and 30% improvements in [immune function](/ingredients/condition/immune-support) markers including increased NK cell activity. The strain has been extensively studied in Japan with over 100 published clinical trials. Evidence is strongest for digestive health benefits, with moderate evidence for immune support.

## Nutritional Profile

{"macronutrients": {"carbohydrates": "3.1g per 100ml", "protein": "1.0g per 100ml", "fat": "0.1g per 100ml"}, "micronutrients": {"calcium": "15mg per 100ml", "sodium": "15mg per 100ml", "potassium": "30mg per 100ml"}, "bioactive_compounds": {"Lactobacillus casei Shirota": "1.0 x 10^10 CFU per 100ml"}, "bioavailability_notes": "The [probiotic](/ingredients/condition/gut-health)s in Yakult are designed to survive passage through the stomach, ensuring delivery to the intestines. The presence of live Lactobacillus casei Shirota enhances gut health and nutrient absorption."}

## Dosage & Preparation

Typical dosages range from 1 to 10 billion CFUs per day, often consumed in the form of a [probiotic](/ingredients/condition/gut-health) drink. Consult a healthcare provider before use.

## Safety & Drug Interactions

Lactobacillus casei Shirota is generally recognized as safe with minimal side effects reported in clinical studies. Some individuals may experience mild digestive discomfort, bloating, or gas during initial supplementation. No significant drug interactions have been documented, though individuals taking immunosuppressive medications should consult healthcare providers. Safety during pregnancy and breastfeeding has not been extensively studied, so consultation with healthcare providers is recommended.

## Scientific Research

Clinical studies have shown that Lactobacillus casei Shirota can help maintain gut health and support the [immune system](/ingredients/condition/immune-support), with several trials backing its efficacy.

## Historical & Cultural Context

Yakult, containing Lactobacillus casei Shirota, has been consumed in Japan and globally for decades as a health-promoting beverage.

## Synergistic Combinations

Bifidobacterium breve, Lactobacillus rhamnosus, [Prebiotic](/ingredients/condition/gut-health) fibers

## Frequently Asked Questions

### How much Lactobacillus casei Shirota should I take daily?

Clinical studies typically use doses of 1-10 billion CFU daily, with most Yakult products containing approximately 6.5 billion CFU per serving. The optimal dose appears to be 6.5-10 billion CFU taken once daily with food for maximum survival and colonization.

### How long does it take for Lactobacillus casei Shirota to work?

Initial digestive benefits may be noticed within 1-2 weeks of consistent use. However, significant improvements in gut microbiome diversity and immune markers typically require 4-8 weeks of continuous supplementation based on clinical trial data.

### Can Lactobacillus casei Shirota survive stomach acid?

Yes, L. casei Shirota demonstrates excellent acid tolerance and bile resistance, with studies showing 70-80% survival rates through gastric transit. This strain was specifically selected for its ability to reach and colonize the small intestine alive.

### What's the difference between Lactobacillus casei Shirota and regular Lactobacillus casei?

L. casei Shirota is a specific patented strain with unique genetic markers and proven clinical benefits. Unlike generic L. casei strains, Shirota has been extensively studied with documented immune-modulating properties and superior intestinal adhesion capabilities.

### Does Lactobacillus casei Shirota need to be refrigerated?

Fresh Yakult products containing L. casei Shirota require refrigeration and have a shelf life of 40 days. However, freeze-dried supplement forms are stable at room temperature for 12-24 months when stored in cool, dry conditions away from direct sunlight.

### Is Lactobacillus casei Shirota safe for children?

Lactobacillus casei Shirota is generally recognized as safe for children and is actually marketed in pediatric-friendly formats like Yakult drinks designed specifically for young ages. Studies support its use in children to support digestive and immune health, though dosing should be age-appropriate. Parents should consult with a healthcare provider to determine the right amount for their child's age and health status.

### What foods contain Lactobacillus casei Shirota naturally?

Lactobacillus casei Shirota is not naturally found in foods—it is a proprietary strain specifically cultivated and added to products, most famously Yakult probiotic drinks. While other fermented foods like yogurt, kefir, and kimchi contain various Lactobacillus species, they do not typically contain the Shirota strain unless explicitly added. If you want this specific strain, you'll need to consume Yakult or supplements containing this documented strain.

### Does Lactobacillus casei Shirota interact with antibiotics?

Lactobacillus casei Shirota may be less effective when taken simultaneously with antibiotics, as antibiotics can kill beneficial bacteria including the probiotic strain. It's generally recommended to take this probiotic at least 2–3 hours apart from antibiotic medications to maximize survival and colonization. Discuss timing with your healthcare provider to ensure optimal effectiveness of both the antibiotic and the probiotic.

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*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
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