From the Guidelines
Currently, there is no strong scientific evidence that specific probiotics directly cause anxiety in most people. In fact, some research suggests certain probiotics may help reduce anxiety symptoms through the gut-brain axis, as seen in the context of irritable bowel syndrome and mental health comorbidity management 1. However, some individuals might experience temporary digestive discomfort when starting probiotics, such as bloating or gas, which could potentially contribute to feelings of unease or anxiety in sensitive individuals. Some key points to consider when evaluating the relationship between probiotics and anxiety include:
- The effects of psychobiotics, including probiotics, on mental health outcomes like depression have been studied, with evidence suggesting small but positive effects, particularly in populations with a formal diagnosis of depression 1.
- The concept of a "psychobiotic" diet rich in prebiotics and fermented foods has been explored for its potential impact on perceived stress in healthy individuals, indicating a broader potential for dietary interventions to influence psychiatric outcomes 1.
- Common probiotic strains like Lactobacillus and Bifidobacterium species are generally considered safe for most people, though individual reactions can vary. If you're concerned about probiotics affecting your anxiety levels, it's advisable to:
- Start with a low dose and gradually increase it while monitoring your symptoms.
- Choose high-quality, well-researched probiotic products.
- Consult with a healthcare provider before starting any supplement regimen, especially if you have pre-existing anxiety or other mental health conditions. The relationship between gut bacteria and mental health is complex and individualized, so what works well for one person may affect another differently, highlighting the need for personalized approaches to using probiotics or other psychobiotics for mental health support 1.
From the Research
Probiotics and Anxiety
There is limited research directly linking specific probiotics to anxiety. However, some studies suggest that certain probiotics may have an impact on cognitive function and mood.
- The study 2 found that a multispecies probiotic containing Bifidobacterium bifidum W23, Bifidobacterium lactis W52, Lactobacillus acidophilus W37, Lactobacillus brevis W63, Lactobacillus casei W56, Lactobacillus salivarius W24, and Lactococcus lactis (W19 and W58) reduced cognitive reactivity to sad mood in non-depressed individuals.
- Another study 3 investigated the effects of Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07 on symptoms of bloating in patients with functional bowel disorders, but did not specifically examine anxiety.
- A comparative study 4 evaluated the preventative effects of three probiotics, Bifidobacterium lactis, Lactobacillus casei, and Lactobacillus acidophilus, in a rat model of colitis, and found that each probiotic had its own anti-inflammatory profile.
- The study 5 examined the effects of an oral probiotic combination of Lactobacillus and Bifidobacterium on the gastrointestinal microbiota during antibiotic treatment for Clostridium difficile infection, and found that probiotic treatment altered the microbiota, but did not specifically investigate anxiety.
- A study 6 investigated the survival of Lactobacillus acidophilus and Bifidobacterium bifidum in ice cream for use as a probiotic food, but did not examine the effects of these probiotics on anxiety.
Specific Probiotics
Some probiotics that have been studied for their potential effects on cognitive function and mood include:
- Bifidobacterium bifidum W23
- Bifidobacterium lactis W52
- Lactobacillus acidophilus W37
- Lactobacillus brevis W63
- Lactobacillus casei W56
- Lactobacillus salivarius W24
- Lactococcus lactis (W19 and W58)
- Lactobacillus acidophilus NCFM
- Bifidobacterium lactis Bi-07
Note that the current evidence does not directly link these probiotics to anxiety, and more research is needed to fully understand their effects on cognitive function and mood.